GB2601747A

GB2601747A - Vision Assessment

Info

Publication number: GB2601747A
Application number: GB2019264.7A
Authority: GB
Inventors: Kay Hazel
Original assignee: Kay Pictures Ltd
Current assignee: Kay Pictures Ltd
Priority date: 2020-12-08
Filing date: 2020-12-08
Publication date: 2022-06-15
Also published as: GB202019264D0

Abstract

A method of assessing the vision of a user 4 alters the distance between the user and a symbol or optotype 2 being viewed whilst the size of the symbol may be kept constant. The visual acuity of the user can be defined in terms of the minimum visual angle at which the user is able to identify the optotype. To provide results for self-administration at home, a computing device such as a smart phone and/or laptop may display a symbol when positioned at different distances from a wall 3, receive an input from the user interpreting the symbol at each distance then provide a feedback assessment of vision based on the results. Where space is limited, the distance may be kept constant whilst the size of the optotype is decreased.

Description

Vision assessment

Field of the invention

The present invention relates to a method of, and an apparatus and system for, assessing the vision of a user, such as a child (undergoing treatment for amblyopia) at home.

Background to the Disclosure

Conventional eye tests involve a patient being examined by an eye professional (e.g. an optometrist). In particular, the eye professional may ask the patient to read letters of decreasing size from a chart on a wall.

The first test that described this methodology was the Snellen test, which provides the basis for many vision tests today. Snellen charts typically comprise a plurality of rows of letters of decreasing size. To test visual acuity a patient sits a certain distance away from a Snellen chart and reads letters from the chart. A visual acuity is determined by the final row that the patient is able to correctly interpret.

In the last 50 years a number of adaptations of the original Snellen test have been introduced to improve accuracy, and testability in differentage groups, such as LogMAR tests and LandoIt C tests. All of these tests require the examiner to have expertise to correctly implement the test and interpret the results. Conventional visual acuity tests are not suitable to be used or interpreted by a patient themselves.

Summary of the Disclosure

According to at least one aspect of the present disclosure, there is described an apparatus for assessing the vision of a user, the apparatus comprising: means (e.g. a user interface) for receiving a first result relating to an interpretation of a first symbol at a first distance; means (e.g. the user interface) for receiving a second result relating to an interpretation of a second symbol at a second distance; and means (e.g. the user interface and/or a processor) for providing an assessment of vision based on the first result and the second result.

Preferably, the apparatus comprises means (e.g. the user interface) for receiving a further result relating to an interpretation of a furthersymbol at a further distance: and means (e.g. the user interface and/or a processor) for providing an assessment of vision based on the first result, the second result, and the further result Preferably, the apparatus comprises means (e.g. the user interface) for displaying the first symbol and/or the second symbol to the user.

Preferably, the first symbol and the second symbol are different. -2 -

Preferably, the first symbol and the second symbol comprise symbols of the same size and/or height, preferably the same overall size and/or height.

Preferably, the first symbol and the second symbol comprise optotypes.

Preferably, the second distance is determined based on the firstdistance and/orthe first result.

Preferably, the second distance is greater than the first distance if the first result is positive.

Preferably, the first distance is determined based on a previous assessment.

Preferably, the first distance is determined based on a maximum distance of correct interpretation for a previous assessment. Preferably, the first distance is beneath the maximum distance. Preferably, the first distance is a single increment below the maximum 10 distance.

Preferably, the assessment comprises a qualitative measure.

Preferably, the assessment is arranged to be interpretable only by a further party.

Preferably, the assessment is arranged to show an improvement or worsening as compared to a previous assessment.

Preferably, the assessment is based on the first result, the second result, and a previous result, wherein the previous result is related to a previous vision assessment.

Preferably, the apparatus comprises means (e.g. a memory) for storing a previous assessment, wherein the assessment is based on the first result, the second result, and the previous assessment.

Preferably, the apparatus comprises means for storing (e.g. the memory) a plurality of previous assessments.

Preferably, the assessment relates to each eye of the user. Preferably, the assessment relates to a comparative vision of the eyes of the user.

Preferably, the apparatus comprises means (e.g. a sensor) for determining whether an eye of the user is obscured.

Preferably, the apparatus comprises means (e.g. the sensor) for determining which eye is obscured.

Preferably, the apparatus comprises means (e.g. the user interface and/or the processor) for displaying the first symbol and/or second symbol in dependence on the eye being obscured.

Preferably, the apparatus comprises means (e.g. the user interface) for instructing the user to obscure an eye before displaying the first symbol and/or second symbol. -3 -

Preferably, the apparatus comprises means (e.g. the user interface) forreceiving an activation code. Preferably, the activation code relates to a further party.

Preferably, the means for receiving (e.g. a communication interface and/or the user interface) an activation code comprises one or more of: identifying the user; receiving a passcode; and receiving a one-time password.

Preferably, the apparatus comprises means (e.g. the processor) for determining one or more of: the first symbol, the second symbol, the first distance, and the second distance based on the activation code.

Preferably, the apparatus comprises means (e.g. the processor) for determining one or more of: the first symbol, the second symbol, the first distance, and the second distance in dependence on an input from a f urther party.

Preferably, the means for providing (e.g. the user interface) an assessment comprises one or more of: means for providing an assessment to a further party; and means for transmitting the assessment to a further party.

Preferably, the apparatus comprises means (e.g. the processor) for performing a calibration of the apparatus.

Preferably, the apparatus comprises means (e.g. the processor) fordetermining adisplay size and/or resolution of the apparatus.

Preferably, the apparatus comprises means (e.g. the user interface) for displaying an object; means for receiving an indication of a size of the object; and means for displaying the first symbol and/or the second symbol in dependence on the indication.

Preferably, the apparatus comprises means (e.g. the user interface) for displaying an object; receiving a resizing input from the user; and displaying the first symbol and/or the second symbol in dependence on the indication.

Preferably, the apparatus comprises means (e.g. the processor) for altering the size of the object in dependence on the resizing input Preferably, the apparatus comprises means (e.g. the user interface and/or the processor) for determining a characteristic of a device being used to display the first symbol and/or the second symbol.

Preferably, the characteristic comprises one or more of: a resolution; a display size; a brightness; a speaker volume; and/or a lock time.

Preferably, the means for determining the characteristic comprises means for receiving (e.g. the user interface) a measurement relating to an object. Preferably, the meansfor determining -4 -the characteristic comprises means for receiving (e.g. the user interface) an indication of a distance based on an object displayed on a/the device on which the first symbol and/or the second symbol is to be displayed.

Preferably, the apparatus comprises means (e.g. the processor) for altering a characteristic of the device.

Preferably, the means for altering the characteristic is arranged to alter the characteristic based on an environmental condition.

Preferably, the apparatus comprises means (e.g. a memory) for recording the characteristic.

Preferably, the means for altering the characteristic is arranged to alter the characteristic based on a previous characteristic for a previous assessment.

Preferably, the apparatus comprises means (e.g. the user interface) for receiving a plurality of results at a plurality of distances, wherein the maximum distance is determined based on the receipt of a negative result.

Preferably, the first symbol and the second symbol comprise one or more of: characters; letters; numbers; and pictures.

Preferably, the apparatus comprises means (e.g. a sensor) for determining a distance between a user and the first symbol Preferably, the apparatus comprises a sensor, more preferably a camera.

Preferably, the apparatus comprises means (e.g. the user interface) for displaying the first symbol and/or second symbol in dependence on the user being at the first distance and/or the second distance.

Preferably, the apparatus comprises means (e.g. the user interface) for instructing the user to position themselves at the first distance and/or the second distance.

Preferably, the apparatus comprises means (e.g. a sensor) for determining an offset between the user and the first symbol.

Preferably, the apparatus comprises means (e.g. the processor) for displaying the first symbol and/orsecond symbol in dependence on the offset being negligible, preferably in dependence on the offset being less than lm, less than 0.5m, and/or less than 0.1m.

Preferably, one or more of: the first symbol, the second symbol, the first distance, and the second distance is dependent on a user input.

Preferably, one or more of: the first symbol, the second symbol, the first distance, and the second distance is dependent on an input from a f urther party. -5 -

Preferably, the apparatus comprises means (e.g. a communication interface) for receiving a confirmation from a further party in relation to one or more of: the first symbol, the second symbol, the first distance, and the second distance.

Preferably, the apparatus comprises means (e.g. a communication interface) for receiving ai input from a further party and/or apparatus and/or providing an input to a second party and/or apparatus.

Preferably, the first distance and/or the second distance is less than or equal to 300 centimetres, less than or equal to 240 centimetres, less than or equal to 190 centimetres, less than or equal to 120 centimetres, and/or less than or equal to 60 centimetres.

Preferably, the distance between the first distance and the second distance is less than or equal to 60 centimetres, less than or equal to 50 centimetres, less than or equal to 30 centimetres, and/or less than or equal to 15 centimetres.

Preferably, the apparatus comprises means (e.g. the user interface) for receiving results for a plurality of distances. Preferably, the plurality of distances are selected based on a logarithmic scale.

Preferably, the apparatus comprises means (e.g. the user interface) for receiving results for a plurality of distances, preferably wherein the plurality of distances includes one or more distances in the range of 15 centimetres to 5 metres, more preferably the range 15 centimetres to 300 centimetres, yet more preferablywherein the plurality of distances includes one or more of: 300 centimetres, 240 centimetres, 190 centimetres 150 centimetres, 120 centimetres, 95 centimetres, 75 centimetres and/or 60 centimetres.

Preferably, the apparatus comprises means (e.g. the user interface) for providing feedback, preferably feedback relating to the first result and/or the second result.

Preferably, the apparatus comprises means (e.g. a communication interface) for providing feedback from a f urther party.

Preferably, the assessment is based on information from a previous assessment. Preferably, the assessment comprises a combination of information from a previous assessment and the assessment.

Preferably, the apparatus comprises means (e.g. a memory) for storing the assessment; and/or means for storing a result of the assessment; and/or means for storing a characteristic of the assessment.

Preferably, the assessment is dependent on a visual angle relating to the symbol. -6 -

Preferably, the visual angle is determined using the equation co = tan-1(1=2), where 4i is the visual angle between the user and a single component part of the symbol, h is the height of a component part of the symbol, and D is the distance from the user to the symbol.

Preferably, the first distance and/or the second distance is determined based on a desired visual angle.

Preferably, the first symbol and the second symbol comprise different symbols.

Preferably, the first result and/orthe second result each relate to an interpretation of a plurality of symbols.

Preferably, the apparatus comprises means for displaying (e.g. the user interface) the first symbol at a first time and the second symbol at a second time.

Preferably, the apparatus comprises means (e.g. the user interface) for displaying a plurality of first symbols to the userat the first distance and/or a plurality of second symbols to the user at the second distance.

Preferably, the apparatus comprises means (e.g. the user interface) for displaying a first sub-symbol of the plurality of first symbols to the user at a first time and a second sub-symbol of the plurality of first symbols to the user at a second time.

Preferably, the apparatus comprises means (e.g. the user interface) for displaying a first sub-symbol of the plurality of second symbols to the user at a first time and a second sub-symbol of the plurality of second symbols to the user at a second time Preferably, the apparatus comprises means for displaying (e.g the user interface) a plurality of first symbols and/or second symbols consecutively.

Preferably, the apparatus comprises means for displaying (e.g. the user interface) a plurality of first symbols and/or second symbols as a group of first symbols and/or second symbols.

Preferably, the first result and/orthe second result relates to a correctness of the interpretation of the first symbol and/or the second symbol respectively.

Preferably, receiving the first result and/or the second result comprises receiving a spoken result.

Preferably, receiving the first result and/or the second result comprises receiving a result at a user interface of a device.

Preferably, the first result and the second result relate to a first eye, and the apparatus further comprises: means for means for receiving a third result relating to an interpretation of a third symbol at a the first distance for a second eye; means for receiving a fourth result relating to -7 -an interpretation of a fourth symbol at the second distance forthe second eye and means for providing an assessment of vision based on the first result, the second result, the third result, and the fourth result.

Preferably, the assessment comprises a comparison of the first eye and the second eye.

According to an aspect of the present disclosure, there is described an apparatus comprising: means (e.g. a user interface) for receiving a first result relating to an interpretation of a first symbol at a first distance for a first eye; means (e.g. the user interface) for receiving a second result relating to an interpretation of a second symbol at a second distance for the first eye; means (e.g. the user interface) for receiving a third result relating to an interpretation of a third symbol at the first distance for a second eye; means (e.g. the user interface) for receiving a fourth result relating to an interpretation of a fourth symbol at the second distance for the second eye; and means (e.g. the user interface and/or a processor) for providing an assessment of vision based on the first result, the second result, the third result, and the fourh result.

Preferably, the apparatus is an apparatus for assessing amblyopia.

Preferably, the apparatus is an apparatus for assessing the vision of a child. Preferably, the apparatus comprises a computer device.

Preferably, the apparatus comprises means (e.g. a communication interface) for transmitting the results and/or the assessment to a storage device.

According to an aspect of the present disclosure, there is described a system comprising the aforesaid apparatus.

According to an aspect of the present disclosure, there is described a system comprising: a first apparatus comprising: means (e.g. a user interface) for receiving a first result relating to an interpretation of a first symbol at a first distance; means (e.g. the user interface) for receiving a second result relating to an interpretation of a second symbol at a second distance; and means (e.g. the user interface and/or a processor and/or a communication interface) for providing an assessment of vision based on the first result and the second result; and a second apparatus comprising: means for receiving (e.g. a communication interface) the assessment from the first apparatus.

According to an aspect of the present disclosure, there is described a method of assessing the vision of a user, the method comprising: receiving a first result relating to an interpretation of a first symbol at a first distance; receiving a second result relating to an interpretation of a second symbol at a second distance; and providing an assessment of vision based on the first result and the second result. -8 -

Preferably, the method comprises a computer-implemented method.

According to an aspect of the present disclosure, there is described a computer program comprising software code adapted when executed to carry out the aforesaid method.

According to an aspect of the present disclosure, there is described an apparatus arranged to execute the aforesaid computer program.

Any feature described as being carried out by an apparatus, an application, and a device may be carried out by any of an apparatus, an application, or a device. Where multiple apparatuses are described, each apparatus may be located on a single device.

Any feature in one aspect of the disclosure may be applied to other aspects of the invention, in any appropriate combination. In particular, method aspects may be applied to apparatus aspects, and vice versa.

Furthermore, features implemented in hardware may be implemented in software, and vice versa. Any reference to software and hardware features herein should be construed accordingly.

Any apparatus feature as described herein may also be provided as a method feature, and vice versa. As used herein, means plus function features may be expressed alternatively in terms of their corresponding structure, such as a suitably programmed processor and associated memory.

It should also be appreciated that particular combinations of the various features described and defined in any aspects of the disdosure can be implemented and/or supplied and/or used independently.

The disclosure extends to methods and/or apparatus substantially as herein described with reference to the accompanying drawings.

The disclosure will now be described, by way of example, with reference to the accompanying drawings.

Description of the Drawings

Figure 1 shows a vision test according to the prior art.

Figures 2a and 2b show an optotype that may be used in a vision test.

Figure 3 shows a computer device on which the methods and systems described herein may be implemented.

Figure 4 shows a method of providing an assessment of vision for a user.

Figure 5 shows an iterative method of providing an assessment of vision fora user. -9 -

Figure 6 shows an exemplary method that may form a part of the method of providing ai assessment of vision.

Figure 7 shows exemplary calibration steps that may form a part of the method of providing an assessment of vision.

Description of the preferred embodiments

Referring to Figure 1, there is shown an apparatus for performing a vision test according to the prior art. More specifically, there is shown an example of a Snellen chart 1 (that is not to scale). This Snellen chart comprises a number of rows, with each row comprising optotypes letters of decreasing size.

In order to perform a Snellen test, a user is placed a certain distance away from the Snellen chart 1 and this user then attempts to read each row. By determining the final row that the user is able to read it is possible to obtain a measure of the user's vision (e.g. their visual acuity). More specifically, each row of the Snellen chart relates to a certain vision score, where typically this score relates to a relative vision. For example, a user who can read only the first row of this chart (when the chart is scaled appropriately) might be said to have a visual acuity of 6/60; this means that this user can only see at 6 metres what a person with normal visual acuity can see at 60 metres.

A Snellen test provides useful results when performed in controlled environments; however, this test can be incorrectly administered or misinterpreted when performed by an inexperienced user.

The present disclosure relates to a method of performing a vision test in which the distance between the user and the symbols being viewed is altered. This method may be used to provide a vision test in which the size of the symbols being viewed is constant and can provide more appropriate results for a self-administered test at home.

Referring to Figure 2a, a visual assessment as described herein typically uses optotypes.

Optotypes are symbols for which the weight of the lines of the symbol is equal to the negative space between lines. In other words, in an optotype the width of each of the component parts/lines of the symbol is the same so that each of the component parts subtend one minute of arc at a certain distance. This leads to each component part of the optotype having an equal visual angle when viewed straight on (as is shown in Figure 2a); as a result a small optotype viewed from a close distance will be perceived by the user in the same way as a large optotype viewed from a correspondingly large distance.

Optotypes may be letters, numbers, pictures, or other symbols; in the example of Figure 2a, there is shown an optotype 2 for the letter E. -10 -The vision of a user (e.g. the visual acuity of a user) can be defined in terms of the minimum visual angle at which that user is able to identify the optotype 2; an exemplary visual angle is shown by the angle 4) in Figure 2a. The visual angle is typically interpreted in terms of minutes of arc or arcminutes (where one arcminute is equal to one sixtieth of a degree). The resolution of the human eye is typically approximately one arcminute.

The visual angle 4) of the optotype 2 (that is the angle between the user, e.g. an eye of the user, and a component part of the optotype) depends on the distance between the user and the optotype. This visual angle may be defined as (fJ= 2 * tan-1(9) where 4) is the visual angle between the user and a single component part of the optotype 2, h is the height of a component part of the optotype, and D is the distance from the user to the optotype.

A visual angle 8 may also be considered, where 8 is the visual angle between a user and the whole height H of the optotype 2. In the example of Figure 2a, H = 5h and so 0 = 50. Typically, the visual angle 4) for a component part of the optotype is used to assess vision, since this enables comparisons to be made between optotypes of with a different number of component parts (e.g. where H 0 5h).

Where the user is offset from the centre of the optotype, the component parts of the optotype may no longer have equal visual angles with respect to the user. This lack of equality of visua angles of the component parts can decrease the accuracy of a vision test and so ideally the user is positioned directly in front of the centre of the optotype 2 and straight-on with respect to the optotype. In practice, a small offset typically results in an acceptable discrepancy in the visual angles of the component parts of the optotype and so does not prohibit an accurate assessment of vision being provided.

The visual angle 4) can be used to assess the vision of the user 4; for example, the user may be positioned relative to the optotype 2 such that the visual angle 4) between the user and the optotype is equal to a certain value. The user may then be asked to interpret the optotype (e.g. be asked what letter is shown by the optotype). Based on the user's answer, the vision of the user at this visual angle can be assessed. By obtaining interpretations from the user at a number of visual angles, an assessment of the vision of the user, such as the visual acuity of the user, can be made.

For illustrative purposes Figure 2a shows the optotype in a front-on view; it will be appreciated that typically the user is perpendicular to the plane of the optotype as shown in Figure 2b. In this example, the optotype 2 is placed on a wall 3 the user 4 is then able to stand a distance D away from the wall to view the optotype.

Conventionally, an assessment may be made by an eye professional based on a user reading letters from a Snellen chart. With a Snellen chart, the distance between the userand the letters remains constant, the user is then asked to identify a number of letters on the Snellen chart, where the letters have different heights H. However, there are a number of problems if someone with no training or expertise uses a Snellen chart or a similar vision testing system designed to be used and interpreted by al eye professional. While the testing process may appear straightforward, accurate results can only be obtained when the tester fully understands the test process, the age and eye condition of the patient and the subjective nature of the test. This can result in a self-tester obtaining al incorrect assessment of their eyesight, which could have serious visual consequences.

The present disclosure relates in particular to apparatuses and methods for testing and monitoring vision that are suitable for use away from a clinical environment. These methods may provide a record of vision assessments to a patient, in particular in a simple to viewformat that cannot be misinterpreted by that patient. This ensures that eye professionals will support the use of these apparatuses and methods by their patients.

According to the present disclosure, there is described an alternative method of performing a vision test in which the distance between a user and a symbol being viewed (e.g. the optotype 2) is varied.

In particular, this test may be used to assess amblyopia, which is a childhood condition affecting the development of normal sight in (usually) one eye and requiring regular treatment and vision monitoring.

Typically, this method is performed using a computer device, where the computer device is arranged to display a symbol (e.g. an optotype) and to receive an indication from the user in relation to a user interpreting (e.g. identifying) the symbol. It will be appreciated that various aspects of the invention may be performed by a user instead of by the computer device.

Referring to Figure 3, there is described a computer device 1000 on which the methods disclosed herein may be implemented.

The computer device 1000 comprises a processor in the form of a CPU 1002, a communication interface 1004, a memory 1006, storage 1008, a user interface 1010, and al input device 1012 coupled to one another by a bus 1014.

The CPU 1002 executes instructions, including instructions stored in the memory 1006 and/or the storage 1008.

-12 -The communication interface 1004 enables the computer device 1000 to communicate with other computer devices. The communication interface may comprise a local area network interface, a WiFi interface, a 3G, 4G, or 5G interface, a Bluetooth® interface, and/or a near field communication (NFC) interface.

The memory 1006 stores instructions and other information for use by the CPU 1002. The memory typically comprises both Random Access Memory (RAM) and Read Only Memory (ROM).

The storage 1008 provides mass storage for the computer device 1000. In different implementations, the storage is an integral storage device in the form of a hard disk device, a flash memory or some other similar solid state memory device, or an array of such devices.

The user interface 1010 enables the user to interact with the computer device 1000, e.g. to provide instructions to the CPU 1002 and/or to view information. The user interface may comprise a touchscreen, a mouse, and/or a keyboard.

The input device 1012 enables a user to input information. The input device typically comprises a sensor, such as a camera, a microphone, or an infrared sensor. The input device may be capable of determining the distance to an object in the vicinity of the computer device; for example, the input device may comprise a plurality of cameras that are able to calculate a distance based on a difference between images taken by each camera (and based on a known distance between the cameras).

The computer device is typically in the form of, or comprises, a smartphone and/or a persona computer. The systems and methods disclosed herein may be implemented using such a device, or using a plurality of such devices. For example, the methods may be carried out in a system comprising a plurality of computer devices, where the methods are carried out in part on a first computer device and in part on a second computer device.

Typically, the methods and systems disclosed herein are implemented using an application on the device, where the user may be able to initiate the methods by interacting with the application (e.g. by pressing a 'start test' button).

Referring to Figure 4, there is described a method 10 of assessing the vision of a user based on symbols (e.g. optotypes) presented at a plurality of distances. This method is typically implemented using the computer device 1000; it will be appreciated that one or more of the steps of the method may be performed by the user, by another person, and/or by another computer device.

In a first step 11, the computer device 1000 determines a first distance for the user and in a second step 12, the computer device displays an optotype at the first distance.

-13 -The displaying of the optotype may be dependent on the user being located at this distance. In particular, the computer device 1000 may use the input device 1012 to ensure that the user is located at the correct distance before displaying the optotype.

In a third step 13, the computer device 1000 receives a result for the first distance. The result may comprise an indication of whether or not the user has been able to correctly interpret the optotype (e.g. whether the user has been able to identify the optotype). The result may also comprise an indication of a quality of interpretation. As an example, the optotype may comprise an image, where the user is instructed to determine features of the image (e.g. characters, colours, shapes etc.). The result may then comprise one or more of these features.

Typically, a number of optotypes are shown at the first distance, either simultaneously or sequentially, where the result depends on the number of correctly interpreted optotypes. As an example, correctly identifying three out of five optotypes may be considered to be a successful interpretation; equally, this result may be recorded more specifically (as a 60% success rate). Furthermore, features of an incorrect interpretation may be recorded and/or considered; interpreting an 'N' as an 'H' may be viewed as more positive than interpreting the N' as an '0'.

The computer device 1000 receiving the results typically comprises the user entering (e.g. typing or saying) their interpretation into the computer device. Equally, the user may indicate whether or not they correctly identified the optotype.

In a fourth step 14, the computer device 1000 determines a second distance for the user aid, in a fifth step 15, the computer device displays an optotype at the second distance.

Typically, similar optotypes are displayed at the first distance and the second distance. In particular, the optotype displayed at the second distance typically has a height and/or size that is the same as the optotype displayed at the first distance; f or example, there may be displayed two different letters having the same size.

In some embodiments, there is displayed a first group of optotypes at the first distance and a second group of optotypes at the second distance. In such instances, each group of optotypes may comprise a plurality of optotypes of the same size and/or each group may comprise a number of optotypes of different sizes (e.g. each group may comprise a large optotype and a small optotype).

In a sixth step 16, the computer device 1000 receives a result for the second distance.

In a seventh step 17, the computer device 1000 provides an assessment of the vision of the user based on the results for the first distance and the second distance. -14 -

In a simple example, the results may indicate that the user can correctly interpret an optotype at the first distance but not at the second distance. The assessment may then return the maximum distance at which a user can correctly interpret an optotype and/or an evaluation of the user's visual acuity, such as the visual angle 0 or (1) at the greatest distance where a user can correctly identify a optotype. In some embodiments, the prescribed distances in the test relate to a score along a logarithmic scale.

In some embodiments, the second distance is determined after a result has been received for the first distance; this enables the second distance to be determined in dependence on the result. For example, if the result is positive the second distance may be greater than the first distance and if the result is negative the second distance may be smaller than the first distance.

Equally, the user may be shown optotypes at a plurality of distance before providing results. As an example, the user may be shown an optotype at two different predetermined distances before providing results for both distances.

While this example only considers two distances, it will be appreciated that in a practice any number of distances may be used.

Feedback may be presented to the user following the test (e.g. as part of the assessment) and/or feedback may be provided during the test. The computer device 1 000 may be arranged to indicate whether each result is positive or negative; for example, the user may interpret al optotype and then be shown a tick if they are correct or a cross if they are incorrect. This feedback may be visual and/or aural; for example, a speaker of the computer device may provide the feedback. The provision of feedback during the test can help to keep the user engaged in the test.

In order to compare the results at each distance, the results may be provided in the form of the visual angle 0 or (1), where this visual angle depends on the distance between the user aid the optotype. The first and second distances may then be chosen to provide a particular visual angle. Where the size of the optotype is the same at the first and second distance, the chaige in visual angle (between the first and second position) is dependent only on the difference between the first distance and the second distance.

The computer device 1000 receiving each result typically comprises the user entering that result into the computer device. In some embodiments, the correct result is obscured before this entry occurs to avoid the user providing a false result. This may comprise the optotype being displayed for only a limited amount of time and/or the symbol being hidden once the user has moved from the first and/or second distance (as may be determined by the input device 1012). -15 -

In some embodiments, the computer device 1000 is arranged to receive the result from a distance, e.g. using a microphone. This enables the userto provide the resultwithoutchanging their location and can be particularly useful where a plurality of symbols are shown consecutively at a set distance.

The symbols that are used may be selected by the user and/or by a further party (such as en eye professional in charge of their ongoing care). For example, the method may use characters; letters (e.g. the whole alphabet or a subset of the alphabet); the letters Tr, 'H', 'K, '0', 'N', 'V'; and/or pictures. The decision regarding the optotypes to use may depend on the user and/or the issue being tested. As an example, pictures may be used where the user is a small child, since this may keep the child engaged.

Typically, the computer device 1000 is arranged to instruct the user to place the device at a certain distance before the optotype is displayed so that a user must move themselves (or the device) to move from the first distance to the second distance. In some embodiments, the computer device is arranged to alter automatically the distance between the device and the user to achieve a desired distance; this may, for example, involve the computer device comprising a motor that enables the device to move along a track.

The method 10 of Figure 4 provides an implementation where the optotypes shown at the first distance and the second distance have the same size. It will be appreciated that optotypes with differing properties (e.g. size, colour, shape, etc.) may be shown at the first and second distances. Where the size is changed, a visual angle can be determined based on the size of the symbol and the distance of the user to the device. This may be beneficial where, for example, the user has a limited amount of space; instead of moving further from the device, the user may instruct the device to decrease the size of the optotype.

In practice, this type of test may be used for regular vison assessments to monitor amblyopia, which typically presents in childhood. Therefore, a parent may supervise the testfortheir child, where the child can sit or stand in a fixed location for the duration of the test and the parent can then move the device as required and enter results into the device.

Referring to Figure 5, an iterative method 20 for providing an assessment of vision is shown.

In a first step 21, the computerdevice 1000 determines a minimum distance for a user and, in a second step 22, the computer device displays an optotype at this minimum distance. The minimum distance is typically a distance that will enable the user to clearly interpret the optotype; this may be based on previous assessment results and/or on characteristics of the user (e.g. an age of the user). -16 -

In a third step 23, the computer device 1000 receives a result for the distance and in a fourth step 24, the computer device 1000 determines whetherthe result is positive (e.g. has the user correctly identified the optotype and/or correctly identified a threshold percentage of a group of optotypes).

If the result is positive, then, in a fifth step 25, the computer device 1000 determines an increased distance and, in a sixth step 26, the computer device displays an optotype at the increased distance.

The third to sixth steps 23, 24, 25, 26 are then repeated until the user no longer provides a positive result. When this occurs, in a seventh step, the computer device 1000 provides an assessment of the vision of the user.

The incrementfor each round of testing, e.g. how much the distance changes at each instance of the fifth step 25, may be predetermined or may depend on the answers of the previous round. For example, getting a score of five out of five may result in a large increment and getting a score of three out of five may result in a small increment, where getting a lower score may result in a round being failed.

In a practical example, the computer device may instruct the userto stand one metre from the computer device and then display an optotype. If the user is able to correctly interpret this optotype, e.g. to say a correct letter that is detected by a microphone of the computer device, then the user is instructed to move furtheraway. This process continues until the user is no longer able to provide a correct interpretation.

It will be appreciated that the method may be similarly implemented where the user starts at a maximum distance and the distance decreases until the user gives a positive result.

Equally, a hybrid approach may be used, where the user providing a positive result leads to a follow-up symbol being displayed at an increased distance being determined and the user providing a negative result leads to a follow-up optotype being displayed at a decreased distance (e.g. the user may go from lm to 5m to 7m to 6m). It tends to be preferable to stat at a close distance, since this allows the user to start successfully, which can be encouraging to the user.

Typically, the method is performed repeatedly by the userto track an improvement in eyesight; for example, the user may take a vision test every week.

In such situations, the minimum distance may be based on the maximum distance from a previous test (this maximum distance being the largest distance at which the user correctly interpreted a previous optotype). In particular, the minimum distance may be selected as one -17 -increment below the maximum distance; this provides a time-efficient test while enabling (normally) the user to provide at least one round of positive results.

Basing a minimum distance on a previous test may be used with an iterative method or with another method. For example, such a method may be used in a test where a number of distances greater than the minimum distance is tested (regardless of whether the user provides a positive result at these distances).

This method of assessment is particularly useful for self-assessments, where the user is not able to visit an optician. However, problematically, the user may misinterpretthe results and/or react negatively to the results.

Therefore, in some embodiments, the assessment that is provided by the computer device 1000 is arranged to not be interpretable by the user. This may involve the assessment comprising an indicator, where only a qualified eye professional is informed of the meaning of the indicator (e.g. the result shown to the user may be C#2', where only qualified eye professionals are informed that this refers to 6/6 vision).

Equally, the assessment provided to the user may comprise the maximum distance at which the user can interpret an optotype. This figure gives the user some indication of their results, but is not easily comparable to more conventional eye test results, and so it would not be clear to the user that a certain result is concerning.

Similarly, the user may be provided with a qualitative assessment, such as a letter grade (an 'A' or a '13). This enables a user to see that they are improving without being able to compa-e themselves to others. To ensure this, the qualitative assessment may vary between users, e.g. so that the starting grade for each user is a 'C' and an improved grade relates to an improvement for this user (as opposed to an objective grade).

Furthermore, the step of providing an assessment of the vision to the user may comprise providing the assessment to a further party (such as an eye professional), where this assessment may or may not also be provided to the user.

This enables an eye professional to request that the user undertakes a vision test without needing to trust the results provided by the user. In this regard, where a Snellen test is self-administered the user may apply the test incorrectly and/or convince themselves that they correctly read a number of the letters on the Snellen chart when they did not.

With the present disclosure, the user may provide results to the computer device 1000 at a number of distances with or without being informed of whether the results are correct. The computer device may then assess the vision of the user based on these results and transmit -18 -this assessment to an eye professional. This reduces the trust that the eye professional must place in the user.

Typically, the assessment being provided to an optician comprises the computer device 1000 being arranged to transmit the assessment to a further computer device relating to a further party and/or to present the assessment to the further party.

In some embodiments, the computer device 1000 is arranged to implement a method that is based on an input from, and/or an output to, afurther party, such as an eye professional.

In particular, the method may include an activation step, which is required for the method to proceed. Typically this comprises the computer device 1000 receiving an activation code from a user. The activation code typically relates to a further party (such as an eye professiond), where the computer device may be arranged to identify the activation code, identify the further party and/or determine a distance and/or symbol based on the activation code.

In some embodiments, an eye professional is able to provide an activation code to a user, which activation code may relate to a particular test, user, and/or eye professional; therefore, the activation code can be used to determine appropriate testing parameters for the user.

Similarly, the computerdevice may be arranged to transmit results of the vision testto a further user, where this transmission may be based on the activation code. Therefore, a user is able to enter the activation code and follow instructions fora relevant test (which test is identified from the activation code), where the results are automatically sent to an eye profession d on completion of the test.

The activation code may be a certain passcode (e.g. a one-time password); equally determining an activation code may comprise determining an identity of the user and/or the computer device 1000. This may, for example, comprise the user following a link in an email and/or the user providing a name or login details.

This disclosure also considers a serverthat is arranged to record details of one or more pates (e.g. eye professionals) alongside activation codes and/or other user details. This enables the computerdevice to match these parties to the activation codes and/or users so that the device can transmit results to relevant parties and/or provide details of relevant parties.

The methods described herein may be implemented using an application, which application is arranged to identify the user (e.g. by having the user log in).

The application and/or the computer device 1000 may then be arranged to: -Provide a reminder to the user that they should undertake a test; this is particularly useful where a user is regularly taking tests in order to track visual improvement.

-19 - - Provide an indication of progress; for example the application may display a graph of maximum interpreting distance against time and/or the application may provide notifications or awards when certain milestones are met.

Transmit results and/or reminders to the user, e.g. via email and/or text.

-Provide details of a relevant further party; in particular, the application may display details of the user's optometrist (e.g. name, qualifications, and/or contact details) and may enable the user to communicate with this optometrist.

An embodiment of a method 30 of assessing the vision of a user that comprises a number of optional features is described with reference to Figure 6. It will be appreciated that an embodiment may implement any combination of the aspects described with reference to Figure 6, and any of the aspects described with reference to Figure 6 may be implemented in isolation.

In a first step 31, the computer device 1000 receives an activation code; as explained above this activation code is typically provided to a user by an eye professional.

In a second step 32, the computer device 1000 determines a relevant test. In some embodiments, this determination is based on the activation code; equally, the determination may be based on a user input. A relevant test may, for example, relate to the types of optotypes that are displayed, or the distances at which the user is assessed.

In a third step 33, the computer device 1000 displays a starting distance and instructs the user to position themselves this far away from the computer device.

In a fourth step 34, the computer device 1000 determines whether the user is correctly positioned (e.g. is at the correct distance).

In some embodiments, the computer device 1000 is arranged to determine the distance of the user from the device. This determination may, for example, comprise the device capturing images from two spaced cameras, identifying the user in each of these images, and then comparing these images to determine a distance of the user from the device.

Equally, the computer device 1000 may receive an indication from the user relating to the distance. For example, the user may move to the correct distance and then say "ready" to indicate that they are at the correct distance/position.

If the user is not correctly positioned, then in a fifth step 35 the computer device 1000 displays a distance prompt. In particular, the device may inform the userto move closeror move further away. -20 -

In a sixth step 36, once the user is the correct distance from the device, the computer device 1000 determines whether the device is correctly angled. It is typically desirable for the user to be looking directly at the centre of the optotype (as opposed to, say, looking up at the optotype), so the computer device may determine whether the user is positioned directly in front of the computer device and/or is looking straight at the device.

This determination of angle may be based on tracking of the user's eyes; in particular, the input device 1012 may be arranged to identify a position of the user's eyes and to determine an angle based on the user's eyes and the position (and orientation) of the device.

If the computer device 1000 is not correctly angled, in a seventh step 37 the computer device 1000 displays an angle prompt; this prompt typically informs the user to tilt the device in a certain direction.

It will be appreciated that the fourth to seventh steps 34, 35, 36, 37 may be performed in any order; for example, the user may determine where to stand to be at the correct distance and then move away from this spot towards the computer device 1000 to tilt the device to the correct angle. Similarly, the user may first place the device at the correct angle/height and then move away from the device until they reach the correct distance.

Typically, this method is performed by a plurality of parties, such as a parent and a child. In this situation, the child may sit or stand in a single location and the parent may then move the computer device 1000 away from the child and/or tilt the device.

In an eighth step 38, once the computer device 1000 is correctly angled, the device determines whether the user's non-tested eye is covered.

In this regard, the vision tests is typically performed on one eye at a time so that a user covers one eye and interprets the optotype using only the other eye. The user may perform the entire test for one eye and then perform another test forthe other eye. Equally the user may test one eye at a certain distance and then test the other eye at this same distance before changing the distance (and then testing each eye again). The choice of which eye to test first may occur automatically (e.g. to default to the right eye) or may be determined by the user and/or the further party. The computer device 1000 may select the eye to be tested (or the order of testing) based on the activation code.

Typically, the method 30 (and each of the other methods 10,20 disclosed herein) is performed for both eyes (e.g. one eye after the other) and the assessment is provided only after both eyes have been tested. In other words, the method may be performed for a first eye and then for a second eye, where an assessment for each eye is presented only after once the testing for the second eye has been completed.

-21 -If the non-tested eye is not covered, then in a ninth step 19, the computer device 1000 displays a prompt for the user to cover that non-tested eye (e.g. the computer device might display the text "cover your left eye").

The covering and/or closure of an eye can be detected using pupil tracking software; if both pupils are detected by such software it can be determined that the user has not covered an eye. The eye that has been covered (e.g. whether the left or right eye is covered) can be determined based on historical data (so that the computer device may identify a previous lime when both of the user's eyes are open and then determine which eye has been closed).

Equally, the determination of whether an eye has been covered may be performed by the user and/or another party (e.g. a parent), where the user or the parent may confirm that the non-tested eye is covered (e.g. by saying "ready").

Furthermore, the computer device 1000 may display such a prompt without performing the eighth step 28. For example, the device may be arranged to display an eye-covering prompt before each displaying an optotype; this prompt may be displayed for a few seconds.

This step may also be performed during a test; for example, the computer device 1000 may be arranged to detect an eye being opened (e.g. via tracking pupil movement) while the optotype is being displayed. The computer device may then disregard the results for this optotype (and/or provide an alert to the user). This can be used to avoid the user peekingwith their 'good' eye.

In a tenth step 40, when the user is positioned correctly, the computer device 1000 is at a correct angle, and the user's non-tested eye is covered, the computer device displays an optotype (and the method proceeds, e.g. as described with reference to Figures 4 and 5).

It will be appreciated that assessments of distance and angle typically may not be exact and so determining the correct distance and angle typically comprises determining whether the user is at substantially the correct distance and/or whether the device is at substantially the correct angle. This determination may be based on the user (e.g. the user may confirm that they are at the right distance and/or that the device is at the right angle), so that the device determining that the user is at the correct distance may comprise the device receiving an indication from the user. In such embodiments, the device may not be able to verify this indication, and so determining that the user is at the correct distance comprises determining that the user is asserting to be at the correct distance.

A potential issue with the vision test described herein is that there may be some variation between the devices that can be used to implement the test. As an example, a user may change the brightness on their device throughout the day and this change in brightness may -22 -cause a change in the test results. This issue might be addressed by the use of a uniformly lit room without windows, which may be used in professional settings. However, such a set-up is not always possible, especially where the test is self-administered.

Therefore, the method may comprise determining and/or altering a parameter of the environment or the computer device 1000. In particular, the method may comprise or more of: - Determining and/or altering a brightness of the computer device 1000 and/or the environment (e.g. the room). In particular, the brightness of the computer device may be altered to correspond to a brightness used for a previous test and/or to account for a change in the brightness of the environment (e.g. as compared to a previous test).

-Determining and/or altering a resolution of the computer device 1000.

- Determining a characteristic of the computer device 1000 (e.g. the screen size). The symbols displayed during the test may depend on this characteristic.

The above steps may be taken in particular to ensure that conditions are the same for multiple tests; for example, where the user takes the test once a week the parameters may be set to be the same for each test. Equally, the parameters may be altered to account for differences in environment. These parameters may then be different for different users and/different computer devices. These parameters and/or the environmental conditions may be included as a part of the assessment (and, e.g., transmitted to an optician) so that the test results can be considered in context.

Typically, the method comprises a calibration step in which a user is instructed to measure and/or alter one or more of the properties of the device. Referring to Figure 7, this calibration step 50 may comprise the user and/or the computer device 1000 altering or adjusting one or more of: - The size of an object on a screen of the computer device 1000. As an example, in a first step 51, an object (e.g. a line) may be shown on the screen, where the user is instructed to measure this object and provide this measurement 52. Equally, the user may be instructed to adjust the line using the user interface to reach a target (e.g. "adjust this line until it is 5cm"). This calibration ensures that the symbols can be displayed at the correct size. Typically, the computer device is arranged to scale the symbols based on this calibration step and/or based on the properties of the screen of the device.

- The brightness of an object on a screen of the computer device 1000. As an example, a user may be presented with three different images of different brightness and instructed to, in a third step 53, alter the screen brightness until one image is visible, one is barely visible, and one is not visible. -23 -

This calibration step 50 may also, or alternatively, comprise the user and/or the computer device 1000 altering or adjusting one or more of: - The proportions of an object on a screen of the computer device 1000. As an example, a quadrilateral may be presented on the screen and the user may be instructed to adjust the width and/or height of the quadrilateral until it forms a square.

- A speaker volume of the computer device 1000. A speaker may be used to provide feedback, where the user may be instructed to seta speaker volume so that this feedback can be heard.

- A lock time and/or a sleep time. The user may be instructed to alter a lock time and/or a sleep time of the computer device 1000 to ensure that the device does not lock during the test.

These properties may be recorded and then used for following tests; for example, the computer device 1000 may be arranged to set the same brightness each time the application is opened. This can ensure that conditions remain constant across tests. The properties may also be modified depending on external features (e.g. the brightness may be recorded relative to the brightness of the environment to ensure a constant ratio across tests).

In some embodiments, the method comprises receiving feedback from a further user. In particular, the methods described herein may be performed under the supervision of an optician, where the optician may be able to communicate with the user to give instructions (e.g. "read the first symbol", or "take one step furtheraway"). This f urther usermay be arranged to observe the test, e.g. this further user may be arranged to watch the user take the test via a camera on the computer device 1000 and/or to share a screen of the computer device.

The feedback from the f urther user may be used to alter a parameter of the test, e.g. to alter the distance at which a symbol is displayed, to alter the size of a symbol, and/or to alter the type of symbol that is displayed.

Furthermore, the determination of a suitable test may be based on input from the further user In a practical example of the method involving a f urther user, an optician may start a video call with the user and then select a test for the user to take based on this video call. The opticial may then alter the parameters of the test based on the user's response; for example, if the optician notices that the user is struggling to correctly interpret a certain letter and/or colour, the optician may alter the test to show this colour more often (or less often).

-24 -Alternatives and modifications It will be understood that the present invention has been described above purely by way of example, and modifications of detail can be made within the scope of the invention.

While the detailed description has primarily considered the varying of a distance between a device and a user, it will be appreciated that aspects of the symbol may also be altered. For example, the size of the symbol may be altered between rounds of testing. This may be particularly useful where a user has a limited amount of space, in such a case the method may comprise displaying a symbol of reduced size if the user is not able to increase the distance between the user and the device While the detailed description has primarily considered the use of a computer device to implement the described methods, it will be appreciated that aspects of the methods may be performed by a human; for example, an optician may be able to determine the first distance and the second distance and instruct a user to move appropriately. However, the use of a computer device is typically preferred since it enables even untrained users to perform the assessment (where the device can then instruct users on how the assessment should be performed).

Reference numerals appearing in the claims are by way of illustration only and shall have no limiting effect on the scope of the claims.

Claims

-25 -Claims 1 An apparatus for assessing the vision of a user, the apparatus comprising: means for receiving a first result relating to an interpretation of a first symbol at a first distance; means for receiving a second result relating to an interpretation of a second symbol at a second distance; and means for providing an assessment of vision based on the first result and the second result.
2. The apparatus of any preceding claim, comprising means for displaying the first symbol at a first time and the second symbol at a second time.
3. The apparatus of any preceding claim, wherein the first symbol and the second symbol comprise symbols of the same height and/or size.
4. The apparatus of any preceding claim, wherein the first symbol and the second symbol comprise optotypes.
The apparatus of any preceding claim, comprising: means for receiving a further result relating to an interpretation of a further symbol at a further distance; and means for providing an assessment of vision based on the first result, the second result, and the further result.
6 The apparatus of any preceding claim, wherein the second distance is determined based on the first distance and/or the first result, preferably wherein the second distance is greater than the first distance if the first result is positive.
7 The apparatus of any preceding claim, wherein the first distance is determined based on a previous assessment, preferably wherein the first distance is determined based on a maximum distance of correct interpretation for a previous assessment, more prefera wherein the first distance is beneath the maximum distance, yet more preferably wherein the first distance is a single increment below the maximum distance.
8 The apparatus of any preceding claim, wherein the assessment comprises a qualitative assessment and/or wherein the assessment is arranged to show a change (e.g. an improvement or worsening) overa previous assessment. -26 -
9 The apparatus of any preceding claim, wherein the assessment relates to each eye of the user, preferably wherein the assessment relates to a comparative vision of the eyes of the user.
10. The apparatus of any preceding claim, comprising means for determining whether an eye of the user is obscured and/or means for instructing the user to obscure an eye before displaying the first symbol and/or second symbol.
11. The apparatus of any preceding claim, comprising means for receiving an activation code, preferably comprising means for determining one or more of: the first symbol, the second symbol, the first distance, and the second distance based on the activation code.
12. The apparatus of any preceding claim, wherein the means for providing an assessment comprises one or more of: means for providing an assessment to a further party; and means for transmitting the assessment to a further party.
13. The apparatus of any preceding claim, comprising means for determining a characteristic of a device being used to display the first symbol and/or the second symbol, prefera wherein the characteristic comprises one or more of: a resolution; a display size; a brightness; a speaker volume; and/or a lock time.
14. The apparatus of claim 13, f urther comprising means for altering the characteristic of the device, preferably wherein the means for altering the characteristic is arranged to alter the characteristic based on an environmental condition.
15. The apparatus of any preceding claim, comprising means for displaying an object on a device being used to display the first symbol and/or the second symbol; means for receiving an indication of a size of the object; and means for displaying the first symbol and/or the second symbol in dependence on the indication.
16 The apparatus of any preceding claim, comprising means for displaying an object on a device being used to display the first symbol and/or the second symbol; means for receiving a resizing input from the user; and means for displaying the first symbol and/or the second symbol in dependence on the resizing input, preferably further comprising means for altering the size of the object in dependence on the resizing input. -27 -
17. The apparatus of any preceding claim, comprising means for determining a distance between a user and the first symbol, preferably comprising a sensor, more prefertly comprising a camera.
18. The apparatus of any preceding claim, comprising means for instructing the user to position themselves at the first distance and/or the second distance.
19. The apparatus of any preceding claim, comprising means for displaying the first symbol and/or the second symbol to the user.
The apparatus of any preceding claim, wherein the first result and/or the second result each relate to an interpretation of a plurality of symbols.
21 The apparatus of any preceding claim, comprising means for displaying a plurality of first symbols to the user at the first distance and/or a plurality of second symbols to the user at the second distance, preferably comprising: means for displaying a first sub-symbol of the plurality of first symbols to the user at a first time and a second sub-symbol of the plurality of firstsymbols to the user at a second time; and/or means for displaying a first sub-symbol of the plurality of second symbols to the user at a first time and a second sub-symbol of the plurality of second symbols to the user at a second time; and/or means fordisplaying a plurality of first symbols and/or second symbols consecutively; and/or means for displaying a plurality of first symbols and/or second symbols as a group of first symbols and/or second symbols.
22 The apparatus of any preceding claim, wherein the f irst result and the second result relate to a first eye, and wherein the apparatus further comprises: means for means for receiving a third result relating to an interpretation of a third symbol at the first distance for a second eye; means for receiving a fourth result relating to an interpretation of a fourth symbol at the second distance for the second eye; and means for providing an assessment of vision based on the first result, the second result, the third result, and the fourth result, preferably wherein the assessment comprises a comparison of the first eye and the second eye -28 -
23 The apparatus of any preceding claim, wherein the apparatus is an apparatus for assessing amblyopia and/or an apparatus for assessing the vision of a child.
24 A system comprising: a first apparatus comprising: means for receiving a first result relating to an interpretation of a first symbol at a first distance; means for receiving a second result relating to an interpretation of a second symbol at a second distance; and means for providing an assessment of vision based on the first result and the second result; and a second apparatus comprising: means for receiving the assessment from the first apparatus.
25. A computer-implemented method of assessing the vision of a user, the method comprising: receiving a first result relating to an interpretation of a first symbol at a first distance; receiving a second result relating to an interpretation of a second symbol at a second distance; and providing an assessment of vision based on the first result and the second result