WO2020141375A1

WO2020141375A1 - Visual receptive field enhancement

Info

Publication number: WO2020141375A1
Application number: PCT/IB2019/060730
Authority: WO
Inventors: Yonathan WEISSLER; Devora NURIEL
Original assignee: Shamir Optical Industry Ltd.
Priority date: 2019-01-01
Filing date: 2019-12-12
Publication date: 2020-07-09

Abstract

An ophthalmic device for enhancing or increasing the number of visual cues in the field of view of a patient, wherein the ophthalmic device is configured to either project light into the central field of view of the patient or deviate light into the central field of view from a direction which is outside the patient's central field of view, and wherein the projected or deviated light forms visual cues.

Description

VISUAL RECEPTIVE FIELD ENHANCEMENT

Background of the Invention The present invention relates to a device and method for preventing the emergence or the progression of myopia.

Near-sightedness, also known as myopia, is a condition of the eye where light from distant objects focuses in front of, instead of on, the retina. This causes distant objects to be seen blurry by the observer while near objects appear normal. Other symptoms may include headaches and eye strain whereas severe near-sightedness increases the risk of retinal detachment, cataracts, and glaucoma. Near-sightedness is the most common eye problem and is estimated to affect 1.5 billion people worldwide (22% of the population).

The exact underlying mechanism for myopia is still not fully understood, however in most cases it is caused by elongation of the eyeball or, less commonly, by the excess of optical power in the eye. There is tentative evidence that the risk of myopia can be decreased by having young children spend more time outdoors.

The juvenile eye typically develops until the age of 18 to 21 years and with it the progression of myopia. By the time the eye fully matures, it may become severely myopic and difficult to treat. Additionally, high myopia has been shown to be associated with retinal detachment and other severe pathologies. Therefore, an effective preventive countermeasure for myopia and its progression has the potential to improve the sight of 2 to 5 billion people worldwide by the year 2050 according to some estimates. Contemporary interventions to prevent juvenile myopia progression include pharmacologic agents, glasses and contact lenses. However, these treatments are less suitable for preventing the emergence of myopia since: the onset of myopia usually occurs before the minimal recommended age for the treatment, the offered treatments may slow the myopia progression but not eliminate the myopia entirely, and these treatments may have considerable side effects.

In general, there are two paradigms striving to prevent myopia or its progression by wearable devices: 1) Orthokeratological remodeling of the eye lens and 2) peripheral defocus\ progressive addition \ multifocal lenses. A multitude of products and inventions are based on these two paradigms or their combination. Eye lens remodeling can be achieved by hard contact lenses, and peripheral defocus using multifocal lenses can be achieved by either contact lenses or by eyeglasses.

However, the peripheral defocus theory does not explain the widespread progression of myopia conclusively, and treatments based on this theory have not been shown as effective in preventing myopia in humans. While the theory assumes that the eye is not in focus across its entire retinal surface simultaneously, it is believed that the peripheral retina can be out of focus, either under or over focused, while the central retina, the fovea, is in sharp focus. Based on this premise, it is speculated that introducing a concentrating lens to the periphery of the field of view will result in reduction of myopia progression rates. However, the exact details of the required optical power and its distribution across the field of view remains uncertain and varies from one treatment to the next.

Spectacles and contact lenses based on these methods have shown only minor improvements in the prevention of myopia in clinical testing. Similarly, orthokeratology should not be considered as a first-line strategy, given the high risk of infectious keratitis and the relatively low patient compliance. Currently, atropine ophthalmic drops seem to be the most effective treatment for slowing the progression of myopia, although the exact mechanism and long-term effectiveness of treatment is still uncertain.

It is, therefore, the object of the present invention to provide an improved device and method for early treatment and/ or prevention of myopia and its progression. Summary of the invention

Visual cues are an integral aspect of the human eye stimulation. One of the undisputed factors in related research is the reduction of myopia prevalence by outdoor time (i.e. time spent outdoor by a patient). One of the key differentiating factors of outdoor visual stimulation versus indoor visual stimulation is the intricacy and small irregular detail richness. Mimicking this aspect of outdoor scenery provides essential visual cues that facilitate normal eye development and reduce unwanted myopic abnormalities.

The main object of this invention is to increase or enhance the number of visual cues in the patient's field of view as outlined in claim 1 and the corresponding method in claim 15 through the use of an ophthalmic device. Preferred embodiments are subject of the dependent claims. One aspect of the present invention is an ophthalmic device for enhancing or increasing the number of visual cues in the field of view of a patient, wherein the ophthalmic device is configured to either project light into the central field of view of the patient or deviate light into the central field of view from a direction which is outside the patient's central field of view, and wherein the projected or deviated light forms visual cues.

Such an ophthalmic device allows an enrichment or increase of details in the visual perception of the user by means of new artificial details superimposed on the image of the physical environment, which results in the treatment and/or prevention of myopia.

In a preferred embodiment of the present invention, the number of visual cues is not enhanced or increased in a central zone of the central field of view of the patient and the number of visual cues is enhanced or increased in a peripheral zone of the central field of view which is at least partially surrounding the central zone of the central field of view. By this means, the comfort for the user of the device is increased by leaving the central part, which is the zone of sharp vision, clean of any added artificial details.

In another preferred embodiment of the present invention, the visual cues appear to the patient at the same distance as other surrounding objects from his environment. By this means, the device is also more comfortable, as the user perceives less the presence of the artificial added details in his visual perception.

Peripheral defocus as discussed in the prior art only brings already existing out-of-focus details into focus using optical power. Existing methods do not address the proposed requirement of increasing the number details seen.

The present invention addresses the aspect of increasing visual details with an ophthalmic device capable of augmenting the viewer's regular vision with additional artificial details. These details are generated over small patches in the field of view. The pattern may change over time and appear over the entire field of view but will preferably be designed with minimal perceptual disturbance for the user.

Such an ophthalmic device enriches the visual perception with new artificial details superimposed on the image of the physical environment. This is a fundamental difference from peripheral defocus devices which do not increase the number of details beyond the naturally occurring values.

The means or devices by which the ophthalmic device according to the invention is configured can, for example, be passive or active means.

Passive means are devices that do not actively produce the light entering the eye, instead they refract, reflect and diffract the light entering the eye from its environment. This is done by multiple small refractive and/or reflective elements on glasses or contact lenses. The optical properties of the elements themselves can be either permanent or changing over time as in the case of electro-active elements. In contrast to other inventions in this field, these elements do not act as lenses and have neutral optical power. Examples are microprisms and mirrors or glitters. With microprisms, light coming from directions different from the central gaze direction is refracted by tiny microprism structures embedded in the lens. By controlling the properties of the microprisms the light is refracted in the same direction of light coming from the gaze direction, causing an augmentation of the regular vision with small and sparse patches containing additional artificial details. With Mirrors or Glitters, light coming from outside the central vision is reflected by a semi-reflective coating over the entire lens or by tiny reflecting elements, such as small mirrors or glitters, embedded in the back surface, front surface and\or inside the lens. Some of the light is reflected in the same direction of the central gaze, causing an augmentation of the regular vision with additional artificial details.

Active Means are devices that actively project high resolution imagery into the eye and are capable of displaying intricate patterns that are rich in small details for extended period as a possible treatment for myopia. These devices include but are not limited to augmented and virtual reality (AR or VR) headsets and screen displays. The augmented reality implementation can superimpose a scene rich in small details over the natural viewing environment.

In a preferred embodiment of the present invention, the ophthalmic device is an active optical means such as a projection system, configured to create and project the light into the field of view of the patient. Such an embodiment allows a precise and continuous adaptation of the enhancement/increase function. Moreover, this function is not dependent on the conditions (e.g. light, number of details, etc.) of the surrounding environment.

In another preferred embodiment of the present invention, the ophthalmic device is a remote screen. In other preferred embodiments of the present invention, the ophthalmic device is a virtual reality (VR) headset or an augmented reality (AR) system

In another preferred embodiment of the present invention, the ophthalmic device is a passive optical means for deviating light from different directions outside the central field of view of the patient into said patient's gaze direction, such as a contact or spectacle lens, comprising: multiple small refractive, diffractive and/or reflective elements, such as micro-prisms, mirrors or glitters, lenslets, or arrays of diffractive elements such as meta-surfaces. Such an embodiment is very stable over time, not requiring the provision of energy. Moreover, this solution can be made very small and light, and therefore, very convenient to wear for a user.

In another preferred embodiment of the present invention, the ophthalmic device is a contact or spectacle lens comprising microprisms and the microprisms are located at least in one of a front surface of the lens, a back surface of the lens or are embedded into the lens. Such an embodiment allows a better adaptation of the deviation of the light rays. It also allows greater deviation angles as other solutions.

In a further preferred embodiment of the present invention, the microprisms are distributed in lattice or concentric rings or randomly. Such an embodiment allows an even distribution of the added artihcial details over the surface of the device.

In another preferred embodiment of the present invention, the microprisms have different geometrical shapes. This provides artificial added details which have different forms corresponding to the geometrical shapes of the microprisms.

In another preferred embodiment of the present invention, the microprisms in the lens increase in size in a peripheral direction of the lens. This is more comfortable for the user by making use of the less sharp human visual perception on the periphery of the field of view.

In a further preferred embodiment of the present invention, the microprisms in the lens increase in distribution density in a peripheral direction of the lens. This is also more comfortable for the user by making use of the less sharp human visual perception on the periphery of the visual field.

In a preferred embodiment of the present invention, the angular size of microprisms in the central field of view is between 5 and 0.16 degrees.

In a preferred embodiment of the present invention, the device comprises a right and a left optical means which are configured differently. Such an embodiment is more comfortable because when an artificial detail is added in the field of view of only one eye it is less perceived by the user. Another aspect of the present invention is a method for preventing the emergence or progression of myopia of a patient, the method including: using an ophthalmic device as discussed above for enhancing or increasing the number of visual cues in the field of view of a patient. Looking through the ophthalmic devices according to the invention and configured with the above-mentioned means will not change the eye’s functionality contrary to looking through concentrating lens which changes the effective focal length of the eye. The long-term effects of interfering with the physiology of the children’s eye for extended periods in the developmental stage is still unknown and might induce unwanted effects as adults, making means like, for example, microprisms preferable in this aspect.

Brief Description of the drawings

The foregoing summary, preferred embodiments and other aspects of the subject-matter of the invention will be best understood with reference to a detailed description of specific embodiments in conjunction with the accompanying drawings in which:

Fig. la is a schematic illustration of one implementation of the invention.

Fig. lb is a schematic illustration of the central and peripheral field of view for a certain gaze direction.

Fig. lc is a schematic illustration of the central and peripheral field of view for another gaze direction.

Fig. 2 illustrates a schematic view through spectacles in an indoor environment.

Fig. 3 illustrates a light refraction mechanism by array of microprisms.

Fig. 4 illustrates how the lens features variable microprisms size corresponding to human visual acuity.

Fig. 5 illustrates various embodiments of the microprism implementation, and some implementations with mirror and filter elements.

Fig. 6 shows a lenslet implementation.

Fig. 7 shows an intrusive prism.

Fig. 8 shows another intrusive prism.

Fig. 9 shows a protrusive prism on a front face.

Fig. 10 shows a protrusive prism on a back face.

Fig. 11 shows a schematic illustration of an augmented reality configuration. Fig. 12 shows a total immersion configuration.

Fig. 13 shows an active configuration with a display.

Fig. 14 shows a top view of an active augmented reality glasses configuration.

Detailed Description of the Invention

Details of the invention will now be described in conjunction with the drawings.

Receptive fields are sensory mechanisms in the retina of the eye fine-tuned for detecting visual patterns, typically at the limit for visual acuity (approx. 60 cpd for adult foveal vision), in the perceived image. ON-Centered receptive fields respond best to a bright spot surrounded by a dark background. OFF-Centered receptive fields respond best to a dark spot surrounded by a bright background. The ON\OFF-centered receptive fields are activated by contrast between bright and dark regions in the image formed on the retina, such as edges and details.

The field of view (FOV) of a person is the entire extent of the observable world that is seen at any given moment by one of the viewer’s eyes - also referred to as monocular field of view. The field of view can change as the viewer moves in space or moves his/her eye in a certain direction.

Visual cues are visual patterns over a certain sector of the field of view that activate many of the receptive fields in the sector.

The gaze direction is the direction in which a viewer must align his eyes in order to see a certain object of interest sharply. This direction is distinct since only a small portion roughly in the middle of the field of view, referred to foveal vision, is available for perceiving small details while the visual acuity in the rest of the field of view is considerably worse. As such, the viewer must fix his gaze on an object in order to align his foveal vision with the direction in space in which the object appears.

The central field of view (Central FOV) is a subset of the field of view in which the viewer has enhanced acuity, i.e. non-peripheral vision. This field is defined as an angular area surrounding the gaze direction (+/- 4, 5, 6, 7, 8,10,20) degrees from the central gaze, in all directions).

Regular vision is defined as the unaided vision of the user as viewed through the ophthalmic device with clear (80%, 85%, 90%, 95% or more transmittance) piano lenses (if the ophthalmic device does not feature a prescription). If the ophthalmic device features a prescription, regular vision is defined as the corrected vision of the user as viewed through the ophthalmic device with standard prescribed lenses. Artificial details are visual cues seen by the viewer in a certain sector of the field of view but do not originate from the presence of an actual object in the part of space associated with this field of view sector in regular vision conditions.

A visual patch refers to a small area over the field of view where the seen image may differ from the regular vision image, e.g. by artificial details.

A passive optical system is a device that does not actively produce the light entering the eye, instead it refracts, reflects and diffracts the light entering the eye from its environment. The optical properties of the device can be either permanent or vaiy over time.

An active optical system is a device that actively creates and projects imagery into the eye. These devices include but are not limited to augmented and virtual reality headsets, electronic eyewear (e.g. glasses), and screen displays.

The link between myopia progression and the lack of children outdoor activity in urban areas has been widely established and confirmed. In the recent two decades there is a global tendency for youth and adolescents to spend disproportionately more time indoor rather than outdoor and this change is correlated with the rising risk for myopia worldwide. It is therefore beneficial to consider the differences between the indoor and outdoor environments for possible treatment for myopia. Some important visual aspects of the outdoor environment such as the distance from viewed objects, light intensity and color composition differ significantly from those indoors. Another important aspect is the high degree of complexity and density of visual patterns, naturally occurring outdoor but mostly absent from the indoor scenery. The introduction of such visual patterns to the viewer by artificial means is the focus of the current invention.

As described above, retinal receptive fields are well-known sensory mechanisms in the retina of the eye fine-tuned for detecting small visual patterns in the perceived image. Among the most common receptive fields in the retina are: the ON-centered receptive field which ideally corresponds to a small bright spot in the center and dark surrounding, and the OFF-centered receptive field which ideally corresponds to a dark spot in the center and bright surrounding. Lately, a specific type of neural cells, which is associated with the ON\OFF receptive fields and is found in abundance in the retina, was proposed to play an important role in the myopia progression. It has been proposed that the visual system relies on the ON\OFF receptive held pathway for the development of the eye. Furthermore, it is evident that the presence of ON\OFF- centered receptive fields in the outdoors scenery far exceeds the indoors’. Based on these premises, it is believed that this difference is a major factor contributing to the progression of myopia. Therefore, the invention relates to a novel technique for enriching the visual scenery with small artificial details, suited for the ON\OFF-centered receptive fields, with minimal distortion of the regular vision. This is achieved by an ophthalmic device capable of augmenting the viewer’s regular vision with artificial details that appear over small patches of the field of view. This ophthalmic device has, for example, the following properties:

• The patches may be isolated from each other so as not to block the large portions of the field of view.

• The patches may appear at the same distance from the viewer as other objects the patch surrounding.

• The patches may be distributed over the entire field of view or in certain sectors.

• The patches may be distributed in a form of a lattice (e.g. rhombic, square, hexagonal, rectangular or parallelogram-like lattices or their combinations). Alternatively, the patches may be distributed in concentric rings or in a random manner.

• The patches may be distributed randomly over a defined region.

• In many cases, the shape of the patch is expected to be circular, but it may differ depending on the shape and distance of the device’s optical elements from the eye and the eye’s pupil. The patches may have different geometrical shapes such as triangular, rectangular, oval, circular, etc.

• The size of patches may vary, featuring larger patches in the periphery of the field of view.

• The patch configuration on the right and left lens will differ in order to reduce binocular instances of similar patches

One manifestation of such an ophthalmic device can be, but is not limited to, spectacles or contact lenses that have small prismatic elements, known as microprisms. The microprisms are designed to reflect and refract light coming from different directions in the scenery onto the gaze direction of the viewer. The small size of the microprisms relative to the central field of view assures that the microprisms will not cover it entirely. The lens may or may not have an ophthalmic prescription. This arrangement will result in each microprism redirecting the light from different objects in the user's environment. Since the indoor environment is not uniform in light conditions or visual details, some of the refracted patches will introduce new artificial details to the seen image. For example, light entering the device from ceiling lighting may enter the field of view containing a workspace, introducing bright details, and light entering the device from a dark piece of furniture below the field of view may introduce dark details, as illustrated in Fig. la. The large number of refracted patches will stimulate a sufficient amount of the ON\OFF-centered receptive fields required for a proper eye development. Fig. la shows a schematic illustration of one implementation of the invention. Reference 101 shows the eye of the viewer gazing through a lens 102 at a typical indoor scenery comprising a light source 105, the focus of the scene 103, for example, a person or object of interest, and surrounding furniture 107. An ophthalmic lens 102, suitable for spectacles or contact eyewear, refracts light from different directions in the periphery of vision 106, 108 and incorporates them with/redirects them to light coming from the central field of view 104.

Light rays are coming from the focus of the scene to the eye’s central field of view 104. This part of the scenery is mostly left unchanged by the lens in order to allow the viewer to comfortably experience the focus of the scene.

Reference 105 designates a light source that illuminates the scene, for example, a lamp of any sort, outdoor light coming from a window or any other object that appears brighter than its surrounding, for example, a white ceiling. A light ray 106 is coming directly from the light source and a small part of it is refracted by the lens 102 and incorporated into the focus of the scene. This light is usually brighter than the light coming from other objects in the scene and therefore will be seen by the viewer as a small bright spot/patch inserted into in the scene.

The furniture 107 appears darker than objects in the focus of the scene. Reference 108 designates a light ray coming from a dark object and a small part of it is refracted by the lens 102 and incorporated into the focus of the scene. This light is usually darker than the light coming from other objects in the scene 104 and therefore will be seen by the viewer as a small dark spot/patch augmented in the scene.

In order to prevent visual disturbances or discomfort, the central section of the lens (a circle or oval shape with an estimated diameter of between 3 mm to 10 mm or 4 mm to 10 mm for spectacles lens, and a smaller diameter for a contact lens) may not feature the microprisms and outside the central section the microprisms are distributed randomly.

Fig. lb illustrates the regions referred to as field of view, central field of view and gaze direction. Reference 101b is the eye of the viewer leveling his gaze at a certain object such as a presenter 103b. The field of view is illustrated by the shaded cone 109b. Every object entering the field of view cone will be seen by the viewer including objects located in the field of view periphery such as the books 107b. However, the visual acuity is not the same over the entire field of view and the viewer can see the presenter in much more details than the books. The sector in the field of view where the visual acuity is best is referred to as central field of view and is illustrated by a darker shaded cone 108b. The gaze direction 104b is illustrated by a line pointing in the direction of the central field of view’s center which is fixed on the presenter. In Fig. lc, reference 101c illustrates the eye looking at the same scene but pointing down. The viewer is pointing his gaze 104c at the books 107c and the entire field of view is shifted by this change. In this case, the central field of view is focused on the books and the viewer can see them in more details than the presenter. Fig.2 illustrates the lens effect as seen to the viewer in an indoor scenery. Shown is the illustration of a typical classroom scene 2001. The scene 2001 comprises objects with varying sizes, proximities and degrees of brightness that are distributed all around the field of vision. A spectacles rim (or frame) 2002 holds the lenses and borders the regions in the illustration in which the effect of the lenses takes place. This illustration is not limited to spectacles and can be used for contact lenses as well.

Reference 2003 designates the effect of the lens in the periphery of vision: small and isolated bright and dark patches amid the original scenery. The density of patches is not too high as to prevent the viewer from experiencing the scene and not too low to deprive the vision from a sufficient sensory stimulation of the ON/OFF receptive fields. In order to reduce the cognitive strain, the shape and position of the patches are random, and their size corresponds to the smallest details a typical human vision can resolve. In this way, the augmented patches will cause less diversion of the viewer’s attention. The central part 2004 of the lens corresponds to the central field of view and is free of interferences in order to increase the compliance of usage.

The pattern of patches 2005 is different between the two lenses in order to prevent the appearance of patches in the same position in space for both of the eyes. This mechanism helps to reduce the cognitive strain by means of binocular diffusion: it is easier to ignore the small patch if it obscures a certain object only in one eye but not the other.

Reference 2006 designates the appearance of a bright patch on a darker surrounding and reference 2007 designates the appearance of a dark patch on a brighter surrounding. Fig. 3 illustrates the light refraction mechanism by multiple microprisms 3105. Reference 3001 is a cross-section view of the ophthalmic lens, reference 3002 is the eye of the viewer gazing through the lens and reference 3003 is the bulk of the lens which is made of ophthalmic glass or plastic material and the back surface of the lens (right side) which may be covered by various types of coatings. The lens may feature an ophthalmic prescription or may have neutral optical power (piano lens). Reference 3004 is the front surface of the lens which features the array of refracting microprisms and reference 3005 is a zoom-in view on a small section of the lens with one microprism 3105 embed in the front surface 3007. Reference 3006 designates the lens through which light rays 3008, 3009 are transmitted from the scene to the eye, traversing from left to right. Because of the viewer gaze direction and limited field of view only a small portion of the rays will enter the pupil of the eye. In this particular illustration, only rays exiting the lens in the horizontal direction will enter the eye and rays from other directions are ignored.

Reference 3007 designates the microprism (not drawn to scale) with a triangular shape and a refractive index different from that of the lens bulk. Reference 3008 designates light rays from the central field of vision passing through the lens without crossing the microprism. These rays are seen by the viewer as regular image. Reference 3009 is a light ray from outside the central field of view refracted by the microprism onto the gaze direction of the viewer. This ray is seen by the viewer as a small bright/dark patch. 3010 shows the ray of the patch that refracts as it enters the microprism. The angle of refraction is determined by the refractive index of the microprism.

At 3011, the ray of the patch is reflected by the surface of the prism by means of total internal reflection. The critical angle of incidence below which reflection occurs is determined by respective refractive indexes of the microprism and the lens.

At 3013, the ray of the patch is refracted to the lens to the gaze direction of the wearer. At 3012, the ray of the patch refracts and reflects from the microprism to the lens in the gaze direction of the viewer. The angle of refraction is determined by the refractive index of the microprism and the lens and also by the apex angle of the microprism. Therefore, the direction of reflection and direction of refraction can be manipulated independently by the choice of the prism shape and refractive indexes.

Reference 3101 is a plan view of the lens with the front or back surface of the lens pointing outwards from the page. Reference 3102 is the central section of the lens that acts as regular ophthalmic lens without featuring the microprism array. Reference 3103 is the peripheral section of the lens that also has the microprism array on the front or back surface.

Reference 3104 is a zoom-in view on a small section of the lens with several microprisms 3105 embedded in the front surface. Shown is a collection of several microprisms with varying sizes and orientations. This diversity assures that the microprisms will refract light from different directions in space and the patches will vary in appearance. The microprism is characterized by the desired angle of incidence (AOI) of the ray to be incorporated into the central gaze direction. The microprisms may be located on the lens front and/or back surfaces (i.e. protruding from the lens) and/or embedded (fully or partially) in the lens substrate. The microprism maybe realized either by an optical structure with a certain shape and refractive index, or by a cavity with a certain shape located inside or on the surface of a bulk optical structure with refractive index different than of the cavity. The microprisms may be isolated from each other so as not to block the large portions of the field of vision. The microprism may appear over the entire field of vision or in certain sectors. The microprisms may be distributed in a form of a lattice (e.g. rhombic, square, hexagonal, rectangular or parallelogram like shape lattices or their combinations). Alternatively, the microprisms may be distributed in concentric rings or in a random manner. The microprisms may be distributed randomly over a defined region.

The size, shape and/or refractive index of the microprisms and/or the density of the microprism distribution may vary over the lens area. The optical device may feature larger patches in the periphery of the lens, according to the variability in human visual acuity. An illustration of an example of how the microprism size may vary according to distance from the central field of view can be seen in Fig. 4.

The shape of the microprism may take the form of any polyhedron. Specifically, but not limited to triangular, quadrangular, pentagonal and hexagonal prisms. The base of the prism may be a regular or irregular arbitrary polygon and the lateral faces of the prism may be right or oblique. The type of the prism may be any of the following: equilateral, Littrow, right angle, Amici Roof, Schmidt, trihedral, wedge, rhomboid, Dove, light pipe. The faces of the prism maybe coated with a light reflecting/ absorbing surface material. The orientation of the microprisms maybe designed to redirect light from certain directions in space or at random.

The distribution of the microprisms may be sparser in the center, and denser in the periphery.

Fig. 4. illustrates how the lens features variable microprisms size corresponds to human visual acuity. Reference 4001 is a front view of the lens with the front surface of the lens pointing outwards from the page. The peripheral section is covered by a microprism array that is illustrated by circles with variable size. Reference 4002 shows the central section of the lens where the vision conditions are most important and therefore no microprisms are featured. Reference 4003 is the interior part of the periphery that exerts the smallest microprisms in correspondence to the highest acuity of vision. Reference 4004 is the exterior part of the periphery that exerts the largest microprisms in correspondence to the lowest acuity of vision. Reference 4005 is a graph showing the estimated size of the microprism as a function of the distance from the center of the lens.

Fig. 5 illustrates various embodiments of the microprism implementation, and some implementations with mirror elements. Reference 5001 is a cross-section view of the ophthalmic lens. Reference 5100 is a zoom-in view on a small section of the lens with one protruding microprism 5101 located on the front surface of the lens. The microprism redirects the light ray 5102 from a different direction to the gaze direction. The refractive index of the microprism may differ from the lens bulk or be the same. Reference 5200 is a zoom-in view over an alternative configuration where the light rays 5201 are coming from different directions refracted from multiple faces of the microprism. The microprism is not limited to triangular shape and may have more than three refracting faces. In 5300, the microprism is embedded inside the lens. The light ray 5301 is redirected multiple times before entering the eye. In 5400, the microprisms is located on the back surface. In 5500, a small mirror 5501 is located on the back surface of the lens. The mirror reflects light coming from behind the viewer. In 5600, a small mirror 5601 is located inside the lens and reflects light coming in front of the viewer from a direction different from the gaze direction.

The microprisms maybe combined with an element having an optical power such as a small lens, as illustrated in Fig.6. This configuration may be useful when the distance from the viewer to the objects used for increasing the number of visual cues is different from the distance to the rest of the scene. When viewing an object within 3 to 4 meters of the eye, the eye accommodates in order to view the "near" object in focus, or sharply. In this situation“far” objects fall out of focus and cannot be seen sharply. A prism in combination with a refractive lens with a power of -3.5 to 3.5 Diopters may be used in certain sectors of the lens in order to allow the viewer to gaze simultaneously both at the near/far scene and at the far/near refracted patch. In Fig. 6, reference 6001 shows the eye of the viewer gazing through a lens at the focus of the scene 6002 at a distance greater than 6 meters. A certain object of regard 6004 is located out of the central field of view within 3 to 4 meters away. The viewer’s gaze is fixed at the far focus of the scene and cannot see both the far and near object simultaneously.

However, a small optical complex is provided consisting of a microprism that redirects a small part of the light coming from the near object 6005 and a lens that brings this light into the focus of the viewer. The effect of the lens is limited to the light passing mostly through the microprism and therefore about the same size of the microprism and located in its vicinity. This configuration allows the viewer to see the far objects and a small part of the near object simultaneously. By this mean the small details from the near object may enrich the visual scenery of the far objects. In addition, the function of redirecting the light and the function of condensing\diverging the light may be implemented in the same optical element embedded in the bulk lens.

Table l: Intrusive Prism properties

The prism is embedded inside the front surface of the lens. 7001 illustrates light coming from above the microprism 7003 that is redirected into the gaze direction by refection from two faces of the prism. 7001 illustrates a light coming from below the microprism, refracting from one face of the microprism 7003, reflecting from the second face 7004 by reflective coating or total internal reflection and that is then redirected into the gaze direction 7005 by refraction from the third face 7006. Different orientation of the prism will yield the deviation of light from different direction into the gaze direction.

Fig. 8 shows the same principle design as in Fig. 7, but instead of a prism with a certain refractive index, a cavity is presented with refractive index similar to the air. Fig. 9 shows an example of a protrusive prism front surface design with the following exemplary values:

Table 2: Protrusive Prism properties

The prism is embedded outside the front surface of the lens 9001. 9005 illustrates light coming from above the microprism 9002 that is redirected into the gaze direction 9003 by refraction from the face of the prism 9004. Alternatively, the light may also come from below the prism. The refractive index of the prism can be different or similar to the refractive index of the lens. Different orientation of the prism will yield the deviation of light from different direction into the gaze direction. Fig. 10 shows an example of a protrusive prism back surface design. The principle design is similar to Fig. 9.

The lenses according to the invention are compatible for everyday use both for indoor and outdoor activities and various light conditions. It is most recommended to use the lenses for prolonged indoor activity in which the visual environment is sparse in visual cues. A refractive error correction can be added to the lens according to the user eyeglass prescription. Also, other fields or applications as for young-age hyperopia could be envisaged.

The ophthalmic device according to the invention is preferably configured to increase the amount of details in the perceived image of objects compared to the regular vision by at least 20%, 30%, 40%, 50% without changing more than 5%, 10%, 20% of the regular vision appearance at any given distance from the viewer.

In one embodiment of the invention, the ophthalmic means for configuring the invention are active means, i.e. a devices that actively project high resolution imagery into the eye and that are capable of displaying intricate patterns that are rich in small details. These types of devices include but are not limited to augmented and virtual reality headsets and screen displays.

One augmented reality (AR) solution implementation can superimpose a scene rich in small details over the regular viewing environment and transmit it to the eye. Fig. 11 is a schematic illustration of an augmented reality configuration 1100. A projector 1101 projects light 1102 with an image rich in detail, and the waveguide 1103 directs the light 1105 into the eye 1104. In addition, the regular vision scene light 1106 enters the eye 1104. The result is the regular vision scene augmented with increased detail in a single image. The waveguide 1103 can be a lens, or another adapted optical system. The configuration includes a collimator to collimate the projected light. The AR solution can be implemented in digital eyewear (as illustrated in Fig. 14). The detail signal can be turned on and off according to a therapeutic treatment regimen, or according to another condition, e.g. outdoor vs indoor use, or level of detail in the natural scene. For example, if the patient is viewing a scene rich in detail, the augmented detail signal can be turned off.

Alternatively, a total immersion configuration is illustrated in Fig. 12. The patient wears a headset 1201 over his/her eyes 1104. A signal is projected from a projection system 1202 through a waveguide 1203. The signal 1204 is directed into the eye 1104. In this case, the projected signal 1204 can be a high detail image, video, or game. The level of detail in the detail signal should be higher than that of an average indoor scene by at least 15%, 30%, 40%, or 50%. Another active configuration 1300 is illustrated in Fig. 13. The configuration includes a display 1301 such as an LED, displaying high detail content 1302 to the patient's visual system/ eyes 1104. The content can be a high detail image, video, or game. Alternatively, the content can be a standard computer or television display with standard content (i.e. an operating system, computer program, video display, etc.) with a detail enriching function applied to the graphics displayed to the screen by applying an algorithm or detail image mask to the graphical output. Further, this configuration can be enhanced with a gaze tracking device. If the patient's gaze is tracked, the detail enhancement can be applied only to the region on the display in the patient's central FOV, thereby reducing the overall disruption of the signal. Fig. 14 illustrates a top view of an active AR glasses configuration 1400 with an ophthalmic lens 1401. The lens can have a positive, negative, or neutral optical power. In this configuration, a projection unit 1405 projects a high-resolution detail signal into the lens 1401. In this case, the lens contains wave guide elements (e.g. mirrors) that direct the light into the eye 1104. The light is projected by the projection unit 1205 and is reflected internally through the lens and eventually directed into the eye 1104. The light entering the eye comes both from the natural environment 1402, 1404 and the detail rich signal from the projection system 1403.

The ability to increase the amount of details in a visual image can be quantified by imaging a standard visual pattern by a digital camera under controlled conditions with and without the ophthalmic device and comparing the number of irregular pixels between the two images. The standard visual pattern is a black and white resolution test chart compliant with ISO 12233:2000 with the following specifications:

- The test chart is printed by a high-resolution printer to achieve sharp transitions between black and white areas without aliasing, and attached to a stiff frame (e.g. aluminum) to provide the necessary rigidity. - The height of the picture in the test chart should be at least 30, 40, 50, 80 cm.

The test chart fills the entire field of view of the camera when viewed through the detail enriching ophthalmic device according to the invention.

The test chart is evenly illuminated with halogen lights.

The digital camera has a 24 megapixels sensor (6000X4000) in APS-C format and a prime lens with 19mm focal length and minimal F-number of 2.8. The imaging conditions are standardized by the following setting: Images are taken in compressionless RAW format compliant with Adobe software package.

- Aperture - the aperture is set so that the entire test chart appears in sharp focus.

Exposure time - the exposure is set such that the white parts of the test chart are just below sensor saturation in RAW format, to ensure that the entire dynamic range of the sensor is used.

- All sharpening options and stabilizing systems of the camera or lens are deactivated.

In order to guarantee absolute stability and prevent any motion blur: the camera is mounted on a geared tripod head that is fixed to a heavy-duty studio stand or optical table. Pictures are taken without physical contact with the camera (with a self-timer or a remote control).

- The lowest actual ISO speed of the camera is selected to acquire images with a minimum level of noise.

The Exposure Value (EV) is set to zero.

It must be ensured that the camera sensor and test chart planes are parallel by using a mirror placed flush against the test chart’s boresight. Adequate alignment is achieved when the reflected image of the lens appears at the center of the camera viewfinder.

The ophthalmic device according to the invention is installed in front of the camera lens in the same distance as intended for use or less. If the field of view of the camera exceeds the boundaries of the ophthalmic device, only the portion of image within these boundaries will be regarded in the analysis. The ophthalmic device is aligned with the camera lens in the same manner as it is designed to be aligned with the viewer’s eye. The ophthalmic device can be removed easily in order to ensure the ability to take two succeeding images with and without the ophthalmic device.

The percentage of increase in the amount of details between the enriched and the regular images can be determined as follows:

Standard pre-processing: convert the color image to binary image by converting the color image to gray-scaled image using weighted average. The weights for the red, green and blue channels are 0.299, 0.587 and 0.114 respectively. The binarization of the gray-scaled image can be performed by Otsu’s method.

The percentage of details enrichment is given by:

Where: i. is the number of irregular pixels in the detail enriched image.

ii. is the number of irregular pixels in the regular image.

iii. Irregular pixel is defined as a pixel in the binary image with value that is different from its surroundings:

1. The surrounding of a pixel is defined as the 8 nearest pixels with direct contact to the relevant pixel. Pixels on the border of the image are ignored.

2. A pixel is considered different from its surrounding if more than four pixels in its surrounding have a value different from it.

2) Standard algorithm for measuring the change in the original appearance ii. The change in original appearance is defined by:

Where:

Claims

1. An ophthalmic device for enhancing or increasing the number of visual cues in the field of view of a patient,

wherein the ophthalmic device is configured to either project light into the central field of view of the patient or deviate light into the central field of view from a direction which is outside the patient's central field of view, and

wherein the projected or deviated light form visual cues.

2. An ophthalmic device according to claim l, wherein the number of visual cues is not enhanced or increased in a central zone of the central field of view of the patient and wherein the number of visual cues is enhanced or increased in a peripheral zone of the central field of view which is at least partially surrounding the central zone of the central field of view.

3. An ophthalmic device according to any of the preceding claims, wherein the visual cues appear to the patient at the same distance as other surrounding objects from his environment.

4. An ophthalmic device according to any of the preceding claims, wherein the device is an active optical means such as a projection system, configured to create and project the light into the field of view of the patient.

5. An ophthalmic device according to claim 4, wherein the device is a remote screen.

6. An ophthalmic device according to claim 4, wherein the device is virtual reality (VR) headset.

7. An ophthalmic device according to claim 4, wherein the device is an augmented reality (AR) system

8. An ophthalmic device according to any one of claims 1 to 3, wherein the device is a passive optical means for deviating light from different directions outside the central field of view of the patient into said patient's gaze direction, such as a contact or spectacle lens, comprising:

- multiple small refractive, diffractive and/or reflective elements, such as micro-prisms, mirrors or glitters, lenslets, or

- arrays of diffractive elements such as meta-surfaces.

9. An ophthalmic device according to claim 8, wherein the device is a contact or spectacle lens comprising microprisms and,

wherein the microprisms are located at least in one of a front surface of the lens, a back surface of the lens or are embedded into the lens.

10. An ophthalmic device according to claim 9, wherein the microprisms are distributed in lattice or concentric rings or randomly.

11. An ophthalmic device according to any one of claim 8 or 9, wherein the microprisms have different geometrical shapes.

12. An ophthalmic device according to any one of claims 8 to 11, wherein the microprisms in the lens increase in size in a peripheral direction of the lens.

13. An ophthalmic device according to any one of claims 8 to 12, wherein the microprisms in the lens increase in distribution density in a peripheral direction of the lens.

14. An ophthalmic device according to any one of claims 8 to 13, wherein the angular size of microprisms in the central field of view is between 5 and 0.16 degrees.

15. An ophthalmic device according to any one of claims 8 to 14, wherein the device comprises a right and a left optical means which are configured differently.

16. A method for preventing the emergence or progression of myopia of a patient, the method including:

using an ophthalmic device for enhancing or increasing the number of visual cues in the field of view of a patient according to any of the preceding claims.