WO2021164866A1

WO2021164866A1 - Vision testing sequences

Info

Publication number: WO2021164866A1
Application number: PCT/EP2020/054378
Authority: WO
Inventors: Ola BARTHOLDSSON
Original assignee: Ieye Ab
Priority date: 2020-02-19
Filing date: 2020-02-19
Publication date: 2021-08-26

Abstract

A system (100, 300) for performing a subjective refraction test, the system comprising a controller module (112, 306), and an adaptation module (302) comprising one or more algorithms configured to generate an output based on received data, and a vision test module (304) comprising information relating to one or more vision tests, wherein the adaptation module (302) is configured to receive data from one or more data sources (316), apply the data to the one or more algorithms, and transmit the output of the one or more algorithms to the vision test module (304), the vision test module (304) is configured to determine a vision test instruction based on the received output of the one or more algorithms, and transmit the vision test instruction to the controller module (306), and the controller module (306) is configured to control a subjective refraction system (308) based on the received vision test instruction in order to perform a subjective refraction test on a patient (310).

Description

VISION TESTING SEQUENCES

Field

The present disclosure generally relates to vision testing. In particular, the disclosure relates to a system for subjective refraction testing sequences.

Background

The standard industry method for determining an individual's refractive error is a subjective refraction performed by an eye care professional (ECP), such as optometrists, ophthalmologists and eye doctors. A subjective refraction is a sequence of vision tests, each determining a different vision error and/or status of the eye. To operate existing subjective refraction methods, several years of optometry education and training are required. Generally, only ECPs have the knowledge, skills and education to conduct subjective refractions, diagnose vision errors and treat them accurately. In most EU countries and in the US, ECPs are the only profession legally allowed to diagnose and prescribe vision treatments. ECPs can legally delegate the subjective refraction process to people with little optometry education. In some third- world countries, subjective refractions are often performed by people with little to no optometry education (hereinafter named "technicians"). Hereinafter, ECPs and technicians are collectively named "operators".

A subjective refraction is generally provided by an operator to a patient in an eye clinic, an optical retail store or pharmacy selling prescription glasses, or other location with subjective refraction equipment. A subjective refraction is normally conducted in-person by an operator being in the same room as the patient. A subjective refraction is normally performed using a manually operated or computerised phoropter (the computerised version is hereinafter called “auto-phoropter”), containing trial lenses in different powers, combined with a paper or a computerised eye chart display to determine the ideal correction of various refractive errors.

The subjective refraction uses many vision tests to test various potential vision errors and vision related statuses of the eye(s) and each test uses an iterative process where the operator asks questions to the patient, receives responses, and asks further questions based on the responses. The operator sends instructions, using a controller, control-box or console (hereinafter called “controller”), to the auto-phoropter to adjust lenses in measurement windows and/or to change eye charts on an eye chart display. Typically, the patient will sit behind an auto-phoropter and look at an eye chart through windows with lenses. The operator uses a computerised controller to change lenses and other settings in the auto-phoropter and eye chart display while asking the patient for feedback on which set of lenses give the best vision. The operator repeats the iterative process until the operator determines that a particular combination of the responses received from the patient satisfy one or more conditions indicating that sufficient data has been collected and the test has arrived at an end-point. After such an end-point, the operator makes a decision on which vision test should be selected next. When a number of vision tests has been conducted, the operator may decide that an end-point for the entire subjective refraction has been reached. Thereafter the operator may make a diagnosis and prescribe a treatment for correcting the patient's vision errors.

Subjective refraction controllers normally control around 40 to 60 different vision tests known in the art. A controller has many user interface sub-controllers controlling all functions of the refraction system. Examples are sub-controllers for modifying right and left eye sphere lens power dioptres, cylinder dioptres, cylinder axis, addition dioptres, prism, pupil distance, functions specifying the usage of lensmeter or auto-refractor data, etc. The controller also contains many controllers controlling an eye chart display. Examples are distance and near visual acuity chart types, e.g. numbers, letters etc., various sizes e.g. VA 1.0, VA 0.8, VA 0.6, cross grid, Amsler grid, stereo balance, binocular red-green and astigmatism clock-dial. Controllers can have pre-programmed vision test configurations wherein a vision test has a predefined combination of a chart and lenses. In one example, a cylinder power test may automatically be configured with a dots chart and a cross cylinder lens.

Vision tests to be included in a subjective refraction can be selected manually from a menu on the controller wherein the operator selects one vision test at a time, or the vision tests can be selected by the controller using a static pre-programmed vision test sequence. To operate pre-programmed and manual subjective refractions, several years of optometry education and training are required.

When vision tests are selected manually, the skills and education of the operator are important for accurate diagnosis and prescription. In many cases, user interface content relating to all possible vision tests is available from a main user interface screen, allowing the operator to choose a relevant vision test. Often, some operators select vision tests differently to other operators, as operators may interpret data, previous test results and patient needs differently. When an untrained operator conducts remote subjective refractions, there is a high risk of variances in vision tests conducted on each patient resulting in quality variances and risks of incorrect diagnosis and prescriptions. Furthermore, locations may delegate the operation of a pre-programmed subjective refraction to non-educated technicians. Then there is a high risk of errors as inappropriate vision tests may be selected by the program or the required vision tests may be missed without the technician discovering errors.

When using a pre-programmed sequence there is less dependency upon the skills of the ECP or technician. A static pre-programmed vision test sequence can be pre programmed by the manufacturer, or a setup can be done by an operator. An example pre-programmed vision test sequence can be the following sequence of vision tests: right, left and binocular unaided visual acuity test - right eye best vision sphere - right eye cross cylinder test axis - right eye cross cylinder test cylinder power - right eye red- green test - left eye best vision sphere - left eye cross cylinder test axis - left eye cross cylinder test cylinder power - left eye red-green test - binocular balance test - binocular best sphere - binocular red-green test - addition measurement - near visual acuity test - phoria test - stereo test.

Static pre-programmed vision test sequences are rarely used by ECPs as ECPs normally have the skills to select vision tests manually. Pre-programmed sequences are beneficial when an uneducated technician is delegated to perform a subjective refraction, as there is then a guarantee that all required vision tests are performed on the patient. The problem with static pre-programmed subjective refraction sequences is that they contain a fixed number of vision tests and the tests are in a static sequence. The system does not take into consideration whether the patient needs to be tested on all vision tests or only a subset. The system does not take into consideration whether the patient needs other vision tests not included in the program. The system does not take into consideration whether some vision tests should be at another position in the sequence. The system does not take into consideration whether progress of the refraction or patient variations such as patient's age, visual needs and visual complaints. As an example, a myopic patient aged 20 does not need an addition test, while a patient aged 45 should have an addition test. As another example, a duo-chrome balancing test should be used if patient's visual acuity is different on right and left eye, as opposed to a traditional balancing test. This is known by a skilled ECP, but not by a technician.

Furthermore, it is impossible to anticipate the complete vision testing requirements of a specific patient prior to starting the subjective refraction and it is therefore not optimal to have static pre-programmed sequences for all patients. Current systems can result in unwanted long subjective refraction times. It is of upmost importance to aim for the shortest possible subjective refraction time as many patients easily get tired in the eyes and lose concentration. It is impossible to anticipate the vision testing requirements of a specific patient prior to starting the subjective refraction and it is therefore not optimal to have static pre-programmed sequences for all patients. While a skilled ECP can manually select vision tests using the controller, others such as non-educated technicians do not have such knowledge and skills and will therefore always follow the controller’s programmed vision test sequence.

The methods and systems disclosed herein attempt to mitigate at least some of these issues.

Summary

As discussed above, there is a need for an improved computerised pre-programmed vision testing sequence system that would be able to continuously adapt and customise the vision test sequence during the subjective refraction and automatically select vision tests based on previous vision test results and requirements discovered during the process. Such a system would specifically be beneficial to uneducated technicians that may conduct subjective refractions on delegations from licensed ECPs. The system would minimise the time for a subjective refraction and minimise errors in vision test selection.

The present disclosure provides a subjective refraction system in the form of an automated adaptive vision testing sequencing (AVTS) system capable of determining a sequence of vision tests during a subjective refraction process. An objective of the AVTS system is to generate and optimise an individualised subjective refraction for each patient by dynamically selecting the most optimal vision test to be used at a given time with a minimum of or no human assistance. Another objective is to perform a subjective refraction process in a minimum amount of time, as the quality of a subjective refraction decreases with time as the patient becomes tired and loses concentration. Another objective is to provide a system allowing individuals uneducated in optometry to perform accurate subjective refractions delegated by ECPs.

In accordance with an aspect of the disclosure, there is provided a system for performing a subjective refraction test, the system comprising a controller module, and an adaptation module comprising one or more algorithms configured to generate an output based on received data, and a vision test module comprising information relating to one or more vision tests, wherein the adaptation module is configured to receive data from one or more data sources, apply the data to the one or more algorithms, and transmit the output of the one or more algorithms to the vision test module, the vision test module is configured to determine a vision test instruction based on the received output of the one or more algorithms, and transmit the vision test instruction to the controller module, and the controller module is configured to control a subjective refraction system (SRS) based on the received vision test instruction in order to perform a subjective refraction test on a patient.

Optionally, the one or more vision tests comprises at least one of a visual acuity test, a best vision sphere test, a cross cylinder axis test, a cross cylinder power test, a red- green test, a binocular balance test, a duo-chrome test, a binocular best sphere test, a binocular red-green test, an addition test, a near visual acuity test, a phoria test, a stereo test and a 3D test. Optionally, the one or more vision tests are configured to determine measurements relating to distance vision, astigmatism, near vision and/or visual anomalies of the patient.

Optionally, the data comprises data received from an operator of the subjective refraction test. Optionally, the data is received from the operator via a vision test user interface. Optionally, the data comprises commands relating to operation of at least part of the SRS. Optionally, the data comprises data received from the patient. Optionally, the data is received from the patient via a user interface of the SRS. Optionally, the data comprises data pertaining to the one or more vision test, the age of the patient and/or the current prescription of the patient. Optionally, the data comprises measurement data obtained by the SRS during a previous vision test on the patient. Optionally, the measurement data comprises at least one of a visual acuity value, an objective cylinder power dioptre refraction value, a variance between an objective sphere power dioptre refraction value and a measured sphere power dioptre value, and a variance between right and left eye visual acuity. Optionally, the adaptation module is configured to receive data continuously and in real time. Optionally, the vision test instruction determined by the vision test module is a selection of a next vision test to be performed. Optionally, the vision test instruction determined by the vision test module is an instruction to adapt a currently ongoing vision test.

Optionally, the SRS comprises at least one of an auto-phoropter, an auto-refractor, an eye chart display, a mirror box, and a wavefront aberrometer. Optionally, the eye chart display comprises a distance vision eye chart display and a near vision eye chart display.

Optionally, the controller module is configured to determine if a subjective refraction test end-point has been reached, and if it is determined that a subjective refraction test end-point has been reached, end the subjective refraction test. Optionally, the system is located at a geographically different location from the SRS and/or an operator. Optionally, the SRS is located at a geographically different location from an operator.

In accordance with an aspect of the disclosure, there is provided a method of controlling a subjective refraction test, the method comprising receiving data from one or more data sources, applying the data to the one or more algorithms to generate an output, determining a vision test instruction based on the generated output, and controlling a subjective refraction system (SRS) based on the vision test instruction in order to perform a subjective refraction test on a patient.

Optionally, the method comprises receiving data from an operator of the subjective refraction test. Optionally, the data is received from the operator via a vision test user interface. Optionally, the data comprises commands relating to operation of at least part of the SRS. Optionally, the method comprises receiving data from the patient. Optionally, the data is received from the patient via a user interface of the SRS. Optionally, the patient data is received from another person, not being the patient, via a user interface. Optionally, the data comprises the age and/or the current prescription of the patient. Optionally, the data comprises data pertaining to the one or more vision tests. Optionally, the method comprises receiving measurement data obtained by the SRS during a previous vision test on the patient. Optionally, the measurement data comprises at least one of a visual acuity value, an objective cylinder power dioptre refraction value, a variance between an objective sphere power dioptre refraction value and a measured sphere power dioptre value, and a variance between right and left eye visual acuity. Optionally, the method comprises receiving previous patient prescription data. Optionally, the patient prescription data comprises at least one of a visual acuity value, a prescribed sphere power dioptre value, a prescribed lenstype and a date. Optionally, the method comprises receiving data pertaining to lenstypes and lens treatments. Optionally, the lenstypes and lens treatment data comprises at least one of a varifocal lenstype dioptre value, an anti-reflective lens treatment specification, and a manufacturer name.

Optionally, the method comprises receiving data continuously, and in real-time. Optionally, the vision test instruction determined by the vision test module is a selection of a next vision test to be performed. Optionally, the vision test instruction determined by the vision test module is an instruction to adapt a currently ongoing vision test.

Optionally, the method further comprises determining if a subjective refraction test end point has been reached and if it is determined that a subjective refraction test end-point has been reached, ending the subjective refraction test. Optionally, the method is performed by a system located at a geographically different location from the SRS and/or an operator of the system. Optionally, the SRS is located at a geographically different location from an operator.

The system can adapt the data and content of an ongoing vision test presented to the operator. The disclosed AVTS system therefore does not use a static pre-programmed sequence nor a manually selected sequence per se. Instead, the AVTS system builds a sequence on the fly, presenting the operator with user interface content relating to one vision test at a time. During a subjective refraction utilising the AVTS system, data is collected from a plurality of data sources into a database continuously and in real time. The data is analysed using specific algorithms with the objective to adapt the ongoing subjective refraction continuously and to identify vision anomalies.

As the AVTS system automatically selects vision tests, monitors and proposes testing values and eye charts, and identifies vision anomalies, the AVTS system provides major improvements to existing subjective refraction methods, particularly in the case where they are operated by delegated and uneducated technicians. For example, the system may consider which tests are required and in which order they should be performed. The system can also take into consideration the progress of the refraction and patient variations such as patient's age, visual needs and visual complaints. This can also reduce the subjective refraction time so that subjects do not lose concentration. There is also less dependency upon the skills of an ECP or technician performing the tests.

Brief Description of the Drawings

Exemplary embodiments of the disclosure shall now be described with reference to the drawings in which:

FIG. 1 schematically illustrates a subjective refraction system according to an embodiment of the disclosure;

FIG. 2 shows an example configuration of a subjective refraction system;

FIG. 3 schematically illustrates an adaptive vision testing sequencing system according to an embodiment of the disclosure;

FIG. 4 illustrates an example of a vision test user interface according to an embodiment of the disclosure;

FIG. 5 schematically illustrates an adaptation module according to an example embodiment of the disclosure;

FIG. 6 illustrates an example of the logic of an adaptive vision testing sequencing system,

FIG. 7 is a flow diagram showing a method of performing a subjective refraction using an adaptive vision testing sequencing system; and

FIG. 8 is a block diagram illustrating an exemplary computer system.

Throughout the description and the drawings, like reference numerals refer to like parts. Specific Description

Operations of various methods may be described as multiple discrete actions or operations in turn, in a manner that is most helpful in understanding the claimed subject matter. However, the order of description should not be construed as to imply that these operations are necessarily order dependent. In particular, these operations may not be performed in the order of presentation. Operations described may be performed in a different order than the described embodiments. Various additional operations may be performed and/or described operations may be omitted, split, or combined in additional embodiments.

The term “operator” is to be interpreted herein as a person performing a subjective refraction on a patient. An operator may be an eye care professional (ECP), such as an optometrist, ophthalmologist or eye doctor. The operator may also be any person that is not an ECP, for example, an optician or orthoptists, or another person trained to conduct subjective refractions such as a technician or a nurse. These persons may conduct delegated subjective refractions by delegation of an ECP. The patient is the individual person receiving a subjective and/or objective refraction conducted by the operator. More than one operator may be involved when performing a subjective refraction on a patient. For example, one operator may perform the subjective refraction while another operator may be supervising the subjective refraction in real-time or after the subjective refraction is completed. It is to be understood that the phrase "operator" may be the same as "operators", whereas one operator may perform a different task to another operator, while both are herein named "operators".

Where the description uses the terms "location" or "locations", it is to be understood that this refers to a physical location where one or a plurality of subjective refraction systems are installed. Typical locations are eye clinics, eye doctors, optical stores, offices, factories, department stores, supermarkets, pharmacies, self-service kiosks, freestanding kiosks, stands or units in shopping malls, airports, pharmacies, supermarkets, department store and the like. A location may also include private residences where a patient may conduct subjective refractions using a computing devices or other type of device configured for conducting such as subjective refraction. A location may have separate rooms with subjective refraction system or systems installed in each room, or a location may have one or more subjective refraction systems installed as freestanding units in the reception area, or at other places at the location. Where the description uses the terms "remote" or "remote location", it is to be understood that this means that the operator is geographically at a different physical location to the location where both the patient and the subjective refraction system are physically located. Also included in the definition of a remote location is the case where an operator conducts a remote subjective refraction and the resulting data from the refraction is sent to an ECP located at a third physical location for diagnosis and prescription. Also included in the definition is the case where an ECP is at the same location as both the patient and the subjective refraction system, but an operator is at a different physical location. A different location address may be a different postal address that is not in the same building as the physical location of the subjective refraction system used by the patient. This includes all locations from another building on the same street to locations in other countries. The remote physical location of the operator may be an office, home, cafe or any physical type of location whereas the operator can access the Internet or a suitable data communication network using a device such as a desktop computer, laptop computer, tablet, mobile phone, etc.

Where the description uses the terms "computerised subjective refraction" or "automated computerised subjective refraction", it is to be understood that this means that computerised program code performs a subjective refraction without the assistance of a human person. As an alternative, the human person is only required to supervise, but not operate, one or a plurality of automated computerised subjective refractions. For example, the human person may be limited to diagnosing and prescribing vision correction treatments, such as corrective glasses, lenses or surgery, following the automated computerised subjective refraction.

Where the description uses the terms "refraction" or "refractometry", it is to be understood that this refers to a clinical examination used by the operator to determine a patient's need for refractive correction. The aim of a refraction is to improve current unaided vision or vision with current corrective measures. In some embodiments, a phoropter may be used by the operator to determine a patient's refractive error and the best vision correction treatment to be prescribed. A refraction may be classified as being a subjective or an objective refraction, but in some embodiments may be integrated in one combined subjective/objective refraction process. The term "subjective refraction" is to be understood as a subjective refraction that, in certain embodiments, also includes an objective refraction. A subjective refraction is an attempt to determine, by trial and error using the patient's cooperation, the best vision correction treatment, for example the combination of lenses that will provide the best corrected visual acuity. The patient's cooperation may be by verbal response to questions, or by other response inputting methods, for example using a joystick, touch-screen, mouse, keyboard or other suitable input device.

The term “objective refraction” is used when the refractive error of a patient's eyes is determined without input by the patient. An objective refraction may use an auto refraction, wavefront aberrometer or retinoscope device. In some equipment embodiments, one or more objective refraction devices are incorporated in the same unit as a subjective refraction device. An objective refraction is normally considered as a preliminary test, where the objective measurements are used as reference values during a subjective refraction.

Where the description uses the terms "subjective refraction system (hereinafter named "SRS") or "controlled subjective refraction system", it is to be understood as a system configured to determine the refractive error of a patient, and optionally to prescribe corrective treatment. It shall be understood that any currently available and future available combination of equipment and refraction software applications that can be used to determine the refractive error of a patient's eyes shall be included in the terms "subjective refraction system", and "controlled subjective refraction system".

FIG. 1 schematically illustrates an SRS 100 for performing a subjective refraction, according to an example embodiment of the disclosure. The SRS 100 comprises one or more of an auto-phoropter 102, an auto-refractor 104, an eye chart display 106, and a mirror box 108. These are measurement instruments known in the art. Other known measurement instruments, such as one or more wavefront aberrometers, may also be implemented in the SRS 100. A wavefront aberrometer may be used as an alternative to an auto-refractor 104.

The auto-phoropter 102 may be a computerised auto-phoropter comprising different lenses used for refraction testing of the patient’s eyes. The major components of the phoropter are the battery of spherical and cylindrical lenses, auxiliary lenses such as Maddox rods, filtered lenses, prisms, and the JCC (Jackson Cross-Cylinder). Typically, the patient sits behind the phoropter, and looks through it at a chart placed at optical infinity (e.g. 6 metres), then at near (e.g. 40 centimetres) for patients needing near distance glasses. The operator then changes lenses and other settings normally using a controller, while asking the patient for subjective feedback on which settings gave the best vision. An auto-phoropter, or automated phoropter or digital phoropter or computerised phoropter is normally a standard phoropter that has additional computer processing features and automated systems that allows the operator to control the phoropter using a separate controller, control box or control pad and screen ("controller").

The auto-refractor 104 is a computer-controlled machine that may be used during an eye examination to provide an objective measurement of a patient's refractive error. This is achieved by measuring how light is changed as it enters a patient's eyes. Generally, an auto-refractor 104 is used as a separate preliminary measurement of the refractive error prior to the usage of an auto-phoropter 102, but in some configurations, an auto-refractor may be integrated with an auto-phoropter 102 in one unit.

The eye chart display 106 is an ophthalmic eye chart display used to measure distance and near visual acuity among other vision tests. The eye chart is placed at a standardised distance away from the patient whose vision is being tested. The patient then attempts to identify the symbols (or optotypes) on the eye chart, starting with the larger symbols and continuing with progressively smaller symbols until the patient cannot identify the symbols. The smallest symbols that can be reliably identified is considered the patient's visual acuity. The Snellen chart is the most widely used. Alternative types of eye charts include the logMAR chart, Landolt C, E chart, Lea test, Golovin-Sivtsev table, the Rosenbaum chart, Dots chart, Red-Green chart, and the Jaeger chart, among others. An eye chart is normally in the form of a paper-sheet, a projector, a computer monitor, a space saving chart incorporated within a mirror box. Chart codes and/or chart values may be stored as part of the eye chart display 106. The eye chart display 106 may be configured as two separate charts wherein one chart is for near distance visual acuity testing and the other for far distance visual acuity testing. The eye chart display 106 may be configured as a chart display that can be moved between a first position for testing near vision and a second position for testing distance vision.

The mirror box 108 may contain a set of mirrors configured to achieve a refraction distance of normally 4 to 7 meters with a typical installation distance of 0.4 to 2 meters. The purpose of a mirror box to minimise the space needed for a subjective refraction. A wavefront aberrometer (not shown in FIG. 1) is a computer-controlled machine used during an eye examination to provide an objective measurement of a patient's refractive error. This is achieved by measuring an optic system (eye) at a multitude of points based on wavefront methods. Generally, a wavefront aberrometer is used as a separate preliminary measurement of the refractive error priorto the usage of the auto-phoropter 102, but in some configurations, a wavefront aberrometer may be integrated with an auto-phoropter 102 in one unit.

The measurement instruments are communicatively coupled to an equipment computer 110, which is a computing device associated with the SRS 100, via a bus 114. The equipment computer 110 is communicatively coupled to a controller module 112. The controller module 112 can control one or more of the measurement instruments discussed above based on an operator input. The controller module 112 is either a software application that can be installed on a computer or a hardware device. The controller module 112 may contain control commands for the auto-phoropter 102 and eye chart display 106, as well as the manufacturer's subjective refraction software application(s).

It will be appreciated that a SRS 100 may have various different configurations used in different ways. Any configuration may include one or more computers, speakers, monitors, headphones and a furniture configuration for the devices and a chair for the patient. In one configuration, the SRS 100 may have a computerised auto-phoropter 102, one or two auto-refractors 104, an eye chart display 106 and one or two mirror boxes 108. The eye chart display 106 may be configured as two separate charts wherein one chart is for near distance visual acuity testing and the other for far distance visual acuity testing. This configuration may be used for a combined binocular objective and subjective refraction. In another configuration, the SRS 100 may be configured with a computerised auto-phoropter 102 and an eye chart display 106. The eye chart display 106 may be configured as two separate charts, wherein one chart is for near distance visual acuity testing and the other for far distance visual acuity testing. These are example configurations only, and other suitable configurations will be easily envisaged by the skilled person.

The SRS 100 may additionally or alternatively comprise a subjective refraction software application 116. In this case, the refractive error of a patient may be determined without the use of a refractor lens assembly (i.e. without the use of a phoropter). The subjective refraction software application may be web based or an installed application on a computing device. The computing device may be a laptop, desktop, tablet or mobile phone. The refractive error is determined by the subjective refraction software application by presenting various vision tests and associated eye charts on a computerised screen and allowing the patient to enter responses by various inputting methods. In one embodiment, the subjective refraction software application may be combined with a remote operator that may operate the subjective refraction or supervise the remote refraction.

FIG. 2 illustrates an example configuration of the SRS 100. A subjective refraction unit 202 is shown on the left. In this embodiment, the subjective refraction unit 202 has a mirror box 108 integrated with an auto-phoropter 102 in a single unit to minimise space needed. The mirror box 108 may have both a near and distance eye chart display 106 that can be changed automatically using computing commands from a controller 112. A subjective refraction unit assembly 204 is shown on the right. The assembly 204 comprises the subjective refraction unit 202 mounted on a free-standing table-stand that is mounted on a moveable pillar that can be adjusted in height and is equipped with headphones and microphones for remotely conducted subjective refractions or refractions performed by computer applications without any human assistance.

FIG. 3 illustrates an example embodiment of an adaptive vision testing sequencing (AVTS) system 300. The AVTS system 300 is preferably hosted in a cloud-computing environment. The AVTS system 300 comprises an adaptation module 302, a vision test module 304 and a controller module 306. The adaptation module 302 is operatively coupled with the vision test module 304 and the controller module 306. The AVTS system 300 is communicatively coupled to a controlled SRS 308, such as the SRS 100. The controlled SRS 308 is used by a patient 310 to perform a subjective refraction to determine the patient's refractive errors. The AVTS system 300 is also communicatively coupled to the vision test Ul 312 used by an operator 314 to perform a subjective refraction on the patient 310 using the AVTS system 300 and a controlled SRS 308.

The adaptation module 302 is configured to continuously, in real-time, collect data from a plurality of data sources 316 (as will be described in more detail in relation to FIG.5), data input by the operator 314 via the vision test user interface (Ul) 312, and/or data input by the patient 310 via the controlled SRS 308. The adaptation module 302 is further configured to analyse received data and to determine and transmit instructions to the vision test module 304, as will be described in more detail in relation to FIG. 5. The adaptation module 302 is further configured to determine and transmit instructions to the controller module 306, for example data values and other content that may be adapted in real-time.

The vision test module 304 contains a plurality of stored vision test content and other types of content that may be used during or after a subjective refraction of a patient. The vision test content contained in the vision tests module 304 is part of a subjective refraction with the purpose of determining a specific vision error and/or various statuses of an eye, for example astigmatism and vision anomalies. Examples of vision test contents are an unaided visual acuity test, best vision sphere, cylinder power tests, red- green test, binocular balance test, addition measurement, near visual acuity test, phoria test, and a stereo test. Any number of vision tests may be stored in the vision test module 304. The number of different vision tests available at the vision test module 304 is not fixed. It may vary dependent on the current and future scope of subjective refractions. A stored vision test may contain a user interface specifically designed for performing that specific vision test with user inputting functions specifically adapted to that vision test. The vision test content contained in the vision tests module 304 may also include other types of content, for example vision anomalies, lenstypes, lens treatments and informational content related to a patient, the subjective refraction and various refraction errors. The vision test module 304 transmits vision test instructions to the controller module 306. For example, an instruction may include which vision test content to present at the vision test Ul 312.

While each vision test content may be performed independently of other vision tests, each vision test is linked to one or a plurality of other vision tests in a predefined structure. In an example, the cylinder power right eye test may be linked to the cylinder axis right eye test, left best vision sphere test, binocular sphere test and/or the addition near test. In another example, the right best vision sphere test may be linked to the cylinder power test, left best vision sphere test, and/or red-green test. The vision tests module 304 may selectively provide vision test content and related user interfaces of one of a plurality of vision tests to a user of the AVTS system 300 via one or more of the user interfaces coupled to the AVTS system 300.

Vision tests in the vision test module 304 are generated in a generic format meaning that the vision test Ul 312 and communication commands and instructions transmitted from the vision test Ul 312 to the controller 306 are independent of the program code used by the controlled SRS 308. The same vision test Ul 312 can then be used to operate and control a plurality of different manufacturers’ SRSs. The vision test Ul 312 may be generated to allow the operator 314 to use any computing device with access to the Internet remotely. Examples of such devices are mobile phones, notepads, tablets, laptops, desktops of different brands and sizes or any other device with a processor, RAM memory and a display hosting a web-browser that can connect to the Internet. In one embodiment, the vision test Ul 312 may be an "app" suitable for iOS and Android mobile devices.

The general purpose of the controller module 306 is to present vision tests and other types of user interface content to a patient 310 or an operator 314, and receive, convert and transmit commands to operate aspects of the controlled SRS 308, such as an auto- phoropter and eye chart display. The controller module 306 is normally operated by the operator 314 when performing a subjective refraction.

The controller module 306 receives instructions from the operator 314 via the vision test Ul 312, and converts and transmits commands to the controlled SRS 308. The controlled SRS 308 then executes the received commands. The controlled SRS 308 may be configured to receive commands at a controller module, equipment computer, auto-phoropter or eye chart display. Using the example of SRS 100, commands may be received at the controller module 112, the equipment computer 110, the auto-phoropter 102 and the eye chart display 106. In some embodiments, the controller module 306 preforms the functionality of the controller module of the controlled SRS 308, such that the subjective refraction is controlled by the operator 314.

For example, operator may input right sphere to be -2.00 dioptres on a vision test user interface. The information is transmitted to the controller module and transformed into a control command suitable for the controlled auto-phoropter. This is transmitted to the controlled auto-phoropter, which changes the right sphere lens in the lens battery that is displayed in the right auto-phoropter window in front of the patient's right eye to -2.00 dioptre. The controller module may control any of the devices integrated into the controlled SRS 308, for example auto-refractors, aberrometers, etc. In some embodiments, the controller receives commands and information from auto-phoropter and eye chart display device. The controller module 306 may include a plurality of web based and/or software program applications that can control a variety of SRSs. This allows for universal access to a plurality of controlled SRSs produced by different manufacturers having different proprietary SRS software applications, signal protocols, auto-phoropter and eye chart display operating commands. The operator 314 and/or the patient 310 may input commands or data to the AVTS system 300 via a user interface. The vision test Ul 312, or a user interface of the controlled SRS 308, may allow data to be input data by an individual using a web-based form or software application. The individual may enter the data using text-input or voice- to-text input. Each user interface can be implemented in a wall-mounted touch-screen display, a mobile phone, smartphone, laptop or desktop computer, tablet or a microphone for receiving voice input.

An operator 314 may input instructions or commands that relate to a subjective refraction process. These can be commands relating to the sequence of tests to be performed, or individual aspects of respective tests. A patient 310 may input data such as their age and vision habits. Vision habits describe how the individual mostly and currently uses his/her eyes, for example working at computers, reading at mobile phone, driving, viewing far distances. Vision habits are important factors when interpreting test results and making a diagnosis. Additional data such as individual's phone number, e-mail address, and language preferences can also be input.

The system 300 may be located at a geographically different location to the controlled SRS 308 and the patient 310. Similarly, the system 300 may be located at a geographically different location to the vision test Ul 312 and the operator 314. The controlled SRS 308 and the patient 310 may be located at a geographically different location to the vision test Ul 312 and the operator 314.

The AVTS system 300 can be implemented in various embodiments and contexts. In one embodiment, the AVTS system 300 may be used as part of a comprehensive eye examination, wherein the AVTS system 300 performs the subjective refraction. The comprehensive eye examination may include other parts such as pre-testing measurements using an auto-refractor, lensmeter, tonometer etc., a medical history analysis, a split lamp test, optical coherence tomography, among others. In one embodiment, the AVTS system 300 may act as a stand-alone subjective refraction system complementing an objective refraction or vision screening. The AVTS system 300 provides an improvement to remote subjective refraction methods, specifically when non-optometry skilled and non-optometry educated people perform the subjective refraction.

FIG.4 illustrates an example of a vision test Ul 400, such as the vision test Ul 312. The vision test Ul 400 comprises a test name 402 of the selected vision test to the operator, in this example "Cylinder Power Right Eye". The vision test Ul 400 also comprises the current cylinder power, lensmeter, and auto-refractor values 404. The vision test Ul 400 also comprises operator input options 406 such as "L", and "R", "Same", and "Next" and "Cancel exam".

FIG. 5 schematically illustrates an adaptation module 500, such as the adaptation module 302, according to an example embodiment of the disclosure. The adaptation 500 comprises a continuous real-time data collection module 502, an adaptation module database 504, a continuous real-time data analytics module 506 and a vision test content selector 508. The modules may be separate program applications and storage- media located on different or same computing devices. The modules may be coupled or integrated to each other using specific program applications.

The continuous real-time data collection module 502 may operate prior to and during the time-period when an AVTS sequence is performed by an operator on a patient. The continuous real-time data collection module 502 collects data in real-time from a plurality of data sources 510 to 524. The adaptation module database 504 stores and structures all data received by the continuous real-time data collection module 502.

First data source 510 provides data received from patient's objective refraction measurements, for example sphere, cylinder power, cylinder axis and pupil distance. Second data source 512 provides data received from patient's current glasses measurements, for example sphere, cylinder power, cylinder axis, addition powers and pupil distance. Third data source 514 provides data received from previous vision tests performed during the current AVTS, for example sphere, cylinder power, cylinder axis, addition powers. Fourth data source 516 provides data received from a current, ongoing vision test, for example sphere, cylinder power, cylinder axis, addition powers. Fifth data source 518 provides data received from patient's vision complaints that may be received during an AVTS sequence or prior to an AVTS sequence being initiated. Sixth data source 520 provides data received from an age related addition power database comprising expected addition power values for each possible age of a patient. Seventh data source 522 provides data received from an accommodation related database comprising expected accommodation power values for each possible age of a patient. Eighth data source 524 is a database comprising a plurality of predefined threshold values determining if collected data may be unexpected. The data sources 510 to 524 described herein are examples and may vary with other configurations. There may be additional or fewer sources than shown in FIG. 5. As example, additional data sources may be historical statistical data from a large number of patients with similar vision errors and vision complaints that may be used for predictions, data analytics and machine learning.

The continuous real-time data analytics module 506 utilises specific algorithms to either update an ongoing vision test or, if a vision test is complete, select the following vision test. The continuous real-time data analytics module 506 may also detect vision anomalies, i.e. data values received that are not expected that may lead to real-time vision test interventions. The algorithms use the data stored in the adaptation module database 504 to generate a particular output. The algorithms may be updated manually or by machine learning.

An example of an algorithm that may be used by the continuous real-time data analytics module 506 following a completed right best vision sphere test is the following: “Select right red-green test, if right sphere minus lensmeter right sphere value < -0.50 dioptres, and if lensmeter value does not exist, select right red-green test if right sphere minus auto-refractor right sphere value < -0.50 dioptres; and if not, select right cylinder test if auto-refractor right cylinder measurement dioptre value is < 0.00, and if not, select left best vison sphere test”. Yet another example of an algorithm that may be used following a completed left best vision sphere test is the following: “Select red-green test if left sphere minus lensmeter left sphere value < -0.50 dioptres, and if lensmeter value does not exist, select right red-green test if left sphere minus auto-refractor left sphere value < -0.50 dioptres, and if not, select duo-chrome balancing test, if visual acuity is different for right and left eye and if patient’s age is < 45; and if not, select binocular balancing test if age is < 45; and if not select binocular best vision sphere test”. Yet another example of an algorithm that may be used to update, in real-time, an ongoing cylinder axis vision test is the following: “Change cylinder axis by (current axis + 4) if the axis to be changed is the third movement and if cylinder power is between 0.25 to 0.50 dioptres”.

Furthermore, specific algorithms are used by the continuous real-time data analytics module 506 to identify vision related anomalies using a database with thresholds values. A vision related anomaly is herein defined as values from one vision test or values received from a plurality of vision tests that are outside predefined expected reference thresholds values. Such a vision related anomaly may be caused by diseases, eye injuries, illnesses, accommodation and others that results in not expected responses from the patient. The purpose of these algorithms is to minimise the risk of wrongly prescribing corrective glasses or contact lenses and to identify patients that require a further appointment with an eye doctor. This function is specifically beneficial when conducting remote subjective refractions or by a computer without any human assistance. As example, an algorithm may be used to identify an anomaly as follows: “cylinder dioptre power received from cylinder power test exceeding +/-1.0 cylinder dioptres variance to auto-refractor cylinder power test measurement”. Yet another example of an algorithm to detect vision related anomalies is the following: "the best vision sphere right eye test is not completed within 10 minutes".

The vison test content selector 508 receives output from the continuous real-time data analytics module 506. The output may include instructions to select a specific vision test, or any other relevant output, for example any detected anomalies. In some embodiments, the vison test content selector 508 may determine if instructions received from the continuous real-time data analytics module 506 shall be executed.

The vison test content selector 508 provides output to a vision test module 526, such as the vision test module 304. The vision test module 526 may receive instructions from the vison test content selector 508 to generate and present a specific vision test content or any other content that may be stored and available at the vision test module. The vision test module 526 provides this content to a controller module 528, such as the controller module 306.

The controller module 528 receives content from the vision test module 526 and may also be directly updated from the continuous real-time data analytics module 506 with real-time data or instructions to modify an on-going vision test 530. Upon receiving user interface content from the vision test module 526, the controller module 528 may update and present such content to a user interface 532, such as the vision test Ul 312. The user interface 532 may be implemented by a user web application or software application at an operators computing device. When an operator 314 is presented with updated user interface content 532, such as the vision test Ul 312, the operator may input new data that may be transmitted to controller module 306, and then to the controlled SRS 308.

In general, as an operator 314 interacts with the AVTS system 300 during a vision test sequence, the adaptation module 500 may be configured to continuously, in real-time, evaluate several possible options for next steps and select the best one to optimise the subjective refraction process. In some embodiments, the adaptation module 500 is configured to determine a change in an ongoing vision test. For example, during a cylinder power test, the adaptation module 500 may monitor, in real-time, the progress of the test. The adaptation module 500 may be configured to detect if the objective cylinder power dioptre value of the ongoing vision test, for example received from an auto-refractor or lensmeter, exceeds a predefined threshold value. If so, the adaptation module 500 may be configured to cooperate with the vision test module 526 in real-time to make an adaptation to the cylinder vision test content presentation, for example to present a warning presentation in an effort to inform the operator that cylinder power values are unexpected. The adaptation module 500 may alternatively be configured to adapt the cylinder vision test content such that the operator is prohibited from continuing with the vision test.

In some embodiments, the AVTS system 300 may operate in an automated manner, such that no human operator 314 is required. The AVTS system 300 provides an improvement to current automated subjective refraction methods, as the AVTS system 300 can automatically manipulate and adapt the sequence of vision tests and the operation of an ongoing specific vision test content without the assistance of a human person. An automated computerised subjective refraction may utilise the AVTS system 300 to automatically control an SRS by instructing the controller module 306, 528 to transmit SRS control commands received from a vision test module 304, 526. The commands may be derived automatically by an adaptation module 302, 500, without the need of an operator 314, based on data received from data sources 316, 510-524 and input from a patient 310. The adaptation module 302, 500 may be configured to, evaluate several possible options for the next steps continuously and in real-time, and select the best one to optimise the automated computerised subjective refraction process. In one embodiment, the AVTS system 300 may have an additional module with predefined questions to be read out loud to the patient using text-to-speech application. The questions to be asked may be managed by the adaptation module 302, 500 that may be configured to, evaluate several possible options for the next question continuously and in real-time, and select the best one to optimise the automated computerised subjective refraction process.

FIG. 6 illustrates an example of the logic 600 of an AVTS system, such as the AVTS system 300, 506. At step 602, a first vison test is selected. As discussed above, an AVTS system may comprise around 40 to 50 different vision tests. In FIG. 6, “Vision Test 1" is selected. This may be any suitable vision test to start the sequence, for example a best vision sphere test.

Five possible vision tests may follow on from Vision Test 1. These five vision tests are, in the illustrated example, Vision Tests 3, 6, 8, 11 , 14. Vision Test 1 may also output 15 anomalies. At step 604, a second vision test is selected using the predefined algorithms used by the adaptation module 500. In this case, Vision Test 6 is selected. Five possible vision tests may follow on from Vision Test 6, which may also output a number of anomalies. At step 606, a third vision test is selected using the predefined algorithms used by the adaptation module 500.

This procedure is repeated through steps 608 to 616, where an anomalies content "12" is selected by the adaptation module 500. The adaption module 500 may have selected this content due to the results from the prior vision test. As an example, the prior test may have been a Worth four dot test detecting left eye suppression that may be treated with vision therapy prescribed by an eye doctor. This may then be an end-point for the subjective refraction, as the patient should consult an eye doctor, and that is decided by predefined algorithms used by the adaptation module 500.

The adaptive vision testing sequencing provides an optimisation of each subjective refraction that will result in, mostly, different vision test sequences for different patients. For example, one patient may receive 20 vision tests while another patient may receive only 4 vision tests. Below are examples illustrating various subjective refraction flows.

Vision test flow example patient A: right, left and binocular unaided visual acuity test - right eye best vision sphere - right eye cross cylinder test axis - right eye cross cylinder test cylinder power - right eye red-green test - left eye best vision sphere - left eye cross cylinder test axis - left eye cross cylinder test cylinder power - left eye red-green test - binocular balance test - binocular best sphere - binocular red-green test - addition measurement - near visual acuity test - phoria test - stereo test.

Vision test flow example patient B: right eye best vision sphere - left eye best vision sphere - binocular best sphere - addition measurement - near visual acuity test.

Vision test flow example patient C: right, left and binocular aided visual acuity test - right eye best vision sphere - left eye best vision sphere - duochrome balance test - binocular best sphere - binocular red-green test - phoria test - stereo test. Vision test flow example patient D: right, left and binocular aided visual acuity test - binocular red-green test.

FIG. 7 is a flow diagram showing a method of performing a subjective refraction on a patient 310 using an SRS 100, 308 and an AVTS system 300.

At step 702, data is received from one or more data sources. The data sources may comprise one or more of the data sources 316, 510-524 discussed above. The data may comprise commands relating to operation of at least part of the SRS 100, 308 received from an operator 314 of the subjective refraction test via a vision test user interface 312. The data may comprise the age and/or the current prescription of the patient 310 and be received via a user interface of the SRS 100, 308. The data may comprise measurement data obtained by the SRS 100, 308 during a previous vision test on the patient 310. The measurement data may comprise at least one of a visual acuity value, an objective cylinder power dioptre refraction value, a variance between an objective sphere power dioptre refraction value and a measured sphere power dioptre value, and a variance between right and left eye visual acuity. The data may be received continuously and in real-time.

At step 704, the data is applied to the one or more algorithms to generate an output. This may be performed by an adaptation module 302, 500 of the system 300, and the output is sent to a vision test module 304, 526. The algorithms either update an ongoing vision test or, if a vision test is complete, select the following vision test. The algorithms may also detect vision anomalies, i.e. data values received that are not expected that may lead to real-time vision test interventions. The algorithms may be updated manually or by machine learning.

At step 706, a vision test instruction is determined based on the output generated by the one or more algorithms. The vision test instruction may be a selection of a next vision test to be performed or an instruction to adapt a currently ongoing vision test. The vision tests are configured to determine measurements relating to distance vision, astigmatism and near vision of the patient 310. A vision test may be a visual acuity test, a best vision sphere test, a cross cylinder axis test, a cross cylinder power test, a red- green test, a binocular balance test, a duo-chrome test, a binocular best sphere test, a binocular red-green test, an addition test, a near visual acuity test, a phoria test, a stereo test and a 3D test. At step 708, an SRS 100, 308 is controlled based on the vision test instruction in order to perform a subjective refraction test on the patient 310. This allows aspects of the controlled SRS 308 to be operated. For example, operator may input right sphere to be -2.00 dioptres on a vision test user interface. The information is transmitted to the controller module and transformed into a control command suitable for the controlled auto-phoropter. This is transmitted to the controlled auto-phoropter, which changes the right sphere lens in the lens battery that is displayed in the right auto-phoropter window in front of the patient's right eye to -2.00 dioptre. Any of the devices integrated into the controlled SRS 308, for example auto-refractors, aberrometers, etc., may be controlled.

At step 710, it is determined if a subjective refraction test end-point has been reached. If it is determined that a subjective refraction test end-point has been reached, ending the subjective refraction test. If it is not determined that a subjective refraction test end point has been reached, the method returns to step 704 where a new output and instruction are determined. As such, the method 700 iterates until all necessary vision tests have been performed.

FIG. 8 is a block diagram illustrating an exemplary computer system 800 in which embodiments of the present invention may be implemented. This example illustrates a computer system 800 such as may be used, in whole, in part, or with various modifications, to provide the functions of the disclosed system. For example, various functions may be controlled by the computer system 800, including, merely by way of example, a controller module, a vision test module and an adaptation module.

The computer system 800 is shown comprising hardware elements that may be electrically coupled via a bus 890. The hardware elements may include one or more central processing units 810, one or more input devices 820 (e.g., a mouse, a keyboard, etc.), and one or more output devices 828 (e.g., a display device, a printer, etc.). The computer system 800 may also include one or more storage device 840. By way of example, the storage device(s) 840 may be disk drives, optical storage devices, solid- state storage device such as a random-access memory (“RAM”) and/or a read-only memory (“ROM”), which can be programmable, flash-updateable and/or the like.

The computer system 800 may additionally include a computer-readable storage media reader 850, a communications system 860 (e.g., a modem, a network card (wireless or wired), an infra-red communication device, Bluetooth™ device, cellular communication device, etc.), and a working memory 880, which may include RAM and ROM devices as described above. In some embodiments, the computer system 800 may also include a processing acceleration unit 870, which can include a digital signal processor, a special-purpose processor and/or the like.

The computer-readable storage media reader 850 can further be connected to a computer-readable storage medium, together (and, optionally, in combination with the storage device(s) 840) comprehensively representing remote, local, fixed, and/or removable storage devices plus storage media for temporarily and/or more permanently containing computer-readable information. The communications system 860 may permit data to be exchanged with a network, system, computer and/or other component described above.

The computer system 800 may also comprise software elements, shown as being currently located within the working memory 880, including an operating system 888 and/or other code 884. It should be appreciated that alternative embodiments of a computer system 800 may have numerous variations from that described above. For example, customised hardware might also be used and/or particular elements might be implemented in hardware, software (including portable software, such as applets), or both. Furthermore, connection to other computing devices such as network input/output and data acquisition devices may also occur.

Software of the computer system 800 may include code 884 for implementing any or all of the function of the various elements of the architecture as described herein. For example, software, stored on and/or executed by a computer system such as the system 800, can provide the functions of the disclosed system. Methods implementable by software on some of these components have been discussed above in more detail.

The term “module” may refer to, be part of, or include a processor (shared, dedicated, or group), an electronic circuit, an Application Specific Integrated Circuit (ASIC), and/or memory (shared, dedicated, or group), that store and execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable component(s) that provide the described functionality. The "modules" may be physically located on cloud-servers or on computers with access to data networks or on computing devices that may be located at the location of the subjective refraction systems. Communication between all computing devices, modules and controlled subjective refraction systems may be by utilising Internet, VPN, LAN, WAN, Wi-Fi, Bluetooth, wired and not-wired networks or other types of data communication networks.

It is to be understood that other embodiments may be utilised and structural or logical changes may be made without departing from the scope of the present disclosure. Therefore, the following detailed description is not to be taken in a limiting sense, and the scope of embodiments is defined by the appended claims.

Claims

1. A system (300) for performing a subjective refraction test, the system comprising: a controller module (306, 528); and an adaptation module (302, 500) comprising one or more algorithms configured to generate an output based on received data; and a vision test module (304, 526) comprising information relating to one or more vision tests; wherein: the adaptation module is configured to receive data from one or more data sources, apply the data to the one or more algorithms, and transmit the output of the one or more algorithms to the vision test module; the vision test module is configured to determine a vision test instruction based on the received output of the one or more algorithms, and transmit the vision test instruction to the controller module; and the controller module is configured to control a subjective refraction system “SRS” (100, 308) based on the received vision test instruction in order to perform a subjective refraction test on a patient (310).

2. The system (300) of claim 1 , wherein the one or more vision tests comprises at least one of a visual acuity test, a best vision sphere test, a cross cylinder axis test, a cross cylinder power test, a red-green test, a binocular balance test, a duo-chrome test, a binocular best sphere test, a binocular red-green test, an addition test, a near visual acuity test, a phoria test, a stereo test and a 3D test.

3. The system (300) of claim 1 or 2, wherein the one or more vision tests are configured to determine measurements relating to distance vision, astigmatism, near vision and/or visual anomalies of the patient (310).

4. The system (300) of any preceding claim, wherein the data comprises data received from an operator (314) of the subjective refraction test.

5. The system (300) of claim 4, wherein the data is received from the operator (314) via a vision test user interface (312).

6. The system (300) of claim 4 or 5, wherein the data comprises commands relating to operation of at least part of the SRS (100, 308).

7. The system (300) of any preceding claim, wherein the data comprises data received from the patient (310).

8. The system (300) of claim 7, wherein the data is received from the patient (310) via a user interface of the SRS (100, 308).

9. The system (300) of claim 7 or 8, wherein the data comprises data pertaining to the one or more vision test, the age of the patient (310) and/or the current prescription of the patient.

10. The system (300) of any preceding claim, wherein the data comprises measurement data obtained by the SRS (100, 308) during a previous vision test on the patient (310).

11 . The system (300) of claim 10, wherein the measurement data comprises at least one of a visual acuity value, an objective cylinder power dioptre refraction value, a variance between an objective sphere power dioptre refraction value and a measured sphere power dioptre value, and a variance between right and left eye visual acuity.

12. The system (300) of any preceding claim, wherein the adaptation module (302, 500) is configured to receive data continuously and in real-time.

13. The system (300) of any preceding claim, wherein the vision test instruction determined by the vision test module is a selection of a next vision test to be performed.

14. The system (300) of any of claims 1 to 12, wherein the vision test instruction determined by the vision test module is an instruction to adapt a currently ongoing vision test.

15. The system (300) of any preceding claim, wherein the SRS (100, 308) comprises at least one of an auto-phoropter (102), an auto-refractor (104), an eye chart display (106), a mirror box (108), and a wavefront aberrometer.

16. The system (300) of claim 15, wherein the eye chart display (106) comprises a distance vision eye chart display and a near vision eye chart display.

17. The system (300) of any preceding claim, wherein the controller module (306) is configured to: determine if a subjective refraction test end-point has been reached; and if it is determined that a subjective refraction test end-point has been reached, end the subjective refraction test.

18. The system (300) of any preceding claim, wherein the system is located at a geographically different location from the SRS (100, 308) and/or an operator (314).

19. The system (300) of any preceding claim, wherein the SRS (100, 308) is located at a geographically different location from an operator (314).

20. A method (700) of controlling a subjective refraction test, the method comprising: receiving (702) data from one or more data sources; applying (704) the data to the one or more algorithms to generate an output; determining (706) a vision test instruction based on the generated output; and controlling (708) a subjective refraction system “SRS” (100, 308) based on the vision test instruction in order to perform a subjective refraction test on a patient (310).

21 .The method (700) of claim 20, wherein the one or more vision tests comprises at least one of a visual acuity test, a best vision sphere test, a cross cylinder axis test, a cross cylinder power test, a red-green test, a binocular balance test, a duo-chrome test, a binocular best sphere test, a binocular red-green test, an addition test, a near visual acuity test, a phoria test, a stereo test and a 3D test.

22. The method (700) of claim 20 or 21 , wherein the one or more vision tests are configured to determine measurements relating to distance vision, astigmatism, near vision and/or visual anomalies of the patient (310).

23. The method (700) of any of claims 20 to 22, comprising receiving data from an operator (314) of the subjective refraction test.

24. The method (700) of claim 23, wherein the data is received from the operator (314) via a vision test user interface (312).

25. The method (700) of claim 23 or 24, wherein the data comprises commands relating to operation of at least part of the SRS (100, 308).

26. The method (700) of any of claims 20 to 25, comprising receiving data from the patient (310).

27. The method (700) of claim 26, wherein the data is received from the patient (310) via a user interface of the SRS (100, 308).

28. The method (700) of claim 26 or 27, wherein the data comprises data pertaining to the one or more vision test, the age of the patient (310) and/or the current prescription of the patient.

29. The method (700) of any of claims 20 to 28, comprising receiving measurement data obtained by the SRS (100, 308) during a previous vision test on the patient (310).

30. The method (700) of claim 29, wherein the measurement data comprises at least one of a visual acuity value, an objective cylinder power dioptre refraction value, a variance between an objective sphere power dioptre refraction value and a measured sphere power dioptre value, and a variance between right and left eye visual acuity.

31. The method (700) of any of claims 20 to 30, comprising receiving data continuously, and in real-time.

32. The method (700) of any of claims 20 to 31 , wherein the vision test instruction determined by the vision test module is a selection of a next vision test to be performed.

33. The method (700) of any of claims 20 to 31 , wherein the vision test instruction determined by the vision test module is an instruction to adapt a currently ongoing vision test.

34. The method (700) of any of claims 20 to 33, wherein the SRS (100, 308) comprises at least one of an auto-phoropter (102), an auto-refractor (104), an eye chart display (106), a mirror box (108), and a wavefront aberrometer.

35. The method (700) of claim 34, wherein the eye chart display (106) comprises a distance vision eye chart display and a near vision eye chart display.

36. The method (700) of any of claims 20 to 35, further comprising: determining (710) if a subjective refraction test end-point has been reached; and if it is determined that a subjective refraction test end-point has been reached, ending the subjective refraction test.

37. The method (700) of any of claims 20 to 36, wherein the method is performed by a system (300) located at a geographically different location from the SRS (100,

308) and/or an operator (314) of the system.

38. The method (700) of any of claims 20 to 37, wherein the SRS (100, 308) is located at a geographically different location from an operator (314).