HK1154945B - Methods and apparatuses for enhancing peripheral vision - Google Patents

Description

Method and apparatus for enhancing peripheral vision

Technical Field

The present invention relates generally to methods and apparatus for substantially simultaneously adjusting central and peripheral vision. More particularly, embodiments of the present invention relate to methods and apparatus for adjusting and improving vision substantially beyond central vision.

Background

In the field of methods and apparatus for retarding or eliminating myopia (nearsightedness) in individuals, such retardation or elimination was earlier achieved by controlling off-axis (peripheral) aberrations with respect to manipulating the curvature of the visual image field while providing clear central imaging. This early work was the subject of co-pending and commonly assigned U.S. patent application 11/349,295 filed on 7.2.2006, which was a continuation-in-part of U.S. patent application 10/887,753 (now U.S. patent 7,025,460) filed on 9.7.2004. The entire contents of these documents are incorporated by reference herein as if they were a part of this specification.

These earlier works have involved methods of reducing, retarding or eliminating the progression of refractive errors (including myopia or hyperopia) in individuals by controlling off-axis aberrations by manipulating the curvature of the visual image field in a predetermined manner and ultimately altering, reducing or eliminating elongation of the eye axis. It has been found that peripheral retinal images (i.e., peripheral vision) play an important role in determining eye growth and are an effective stimulus for controlling axial elongation leading to myopia.

Thus, these cited, earlier works focused on methods of retarding (and in many cases preventing or reversing) myopia progression by employing novel optical devices with pre-determined off-axis aberration-controlled designs to retard, reduce or eliminate (undesirable) eye growth.

More specifically, it has been thought that the progression of myopia can be corrected by precise, predetermined control of the off-axis optical correction factor, or aberration of the correction device, or combination of off-axis optical aberrations of the eye and device, thereby allowing the visual image to have a central visual field image position located near the central retina (i.e., fovea) while also having a position located more anterior to (or in front of) the peripheral retina (i.e., toward the cornea or in front of the eye) than would normally be the case under an uncorrected condition or conventional correction device or strategy. This arrangement may minimize or reduce irritation of elongation of the eye axis leading to myopia. And because the device does not cause any central field defocus (e.g., caused by under-correction methods or bifocal or progressive optical devices), the earlier-working devices cited by the present invention provide good visual acuity for the wearer. Thus, these early efforts focused on peripheral visual field manipulation to achieve specific goals of reducing myopia progression.

Research has now found that by accurately positioning or directing the peripheral image on the peripheral retina, selective, highly enhanced peripheral vision can be achieved, while substantially simultaneously achieving corrected, clear central vision. This "wide-angle" vision correction method can achieve greatly enhanced vision, or "global vision" (i.e., improved or enhanced vision in the "globus oculi" range or in the entire field of view including the center and periphery), which can benefit not only those traditionally considered "ametropia" (those with central refractive errors; those generally considered to require refractive vision correction), but also those with peripheral refractive errors but generally considered "ametropia" (those without central refractive errors). This new vision correction method is particularly useful for those with highly selective or specific vision requirements over the peripheral field of view.

Disclosure of Invention

According to embodiments of the present invention, vision is controlled by both central and peripheral vision substantially simultaneously; wherein peripheral vision may include a peripheral central vision zone, or a mid-peripheral vision zone, or a far-peripheral vision zone. This vision control results in improved visual performance by manipulating the individual's imaging focus in positions such that the central and peripheral images are directed purposefully and substantially simultaneously to the central and peripheral retinal surfaces, respectively. Depending on the individual's particular visual needs, the manipulation of the imaging focus position may be, for example, positioning directly on the retina, or having some other positional relationship.

Other objects, advantages and embodiments of the invention will become apparent upon reading the following detailed description of the invention which refers to the accompanying drawings.

Drawings

FIG. 1 is an optical representation showing a central emmetropic but peripheral myopic eye;

FIG. 2 is an optical representation of an eye showing central emmetropia but peripheral hyperopia;

FIG. 3 is an optical representation of an eye showing central myopia and deeper peripheral myopia;

FIG. 4 is an optical representation showing the correction of the eye of FIG. 3 using conventional equipment to cause central correction but peripheral myopia;

FIG. 5 is an optical diagram illustrating correction of the eye of FIG. 3 with both central and peripheral correction using one embodiment of the present invention;

FIG. 6 is an optical representation of an eye showing central hyperopia but peripheral emmetropia;

FIG. 7 is an optical representation showing the correction of the eye of FIG. 6 using conventional equipment to cause central correction while the periphery exhibits myopia;

FIG. 8 is an optical diagram illustrating correction of the eye of FIG. 6 with both central and peripheral correction using one embodiment of the present invention;

figure 9 is a plot of the relationship between measured contrast sensitivity (as a contrast threshold) and the deviation of peripheral refractive state from emmetropia (i.e., peripheral defocus) for three of the tested subjects. Note that a lower contrast threshold indicates better contrast sensitivity, which is a measure or criterion of visual performance.

Figure 10 is a plot of peripheral refractive state versus central refractive state measured at 30 degrees along the horizontal nasal lateral field for 1603 tested right eye.

FIG. 11 is a flow chart describing a protocol for improving and enhancing peripheral visual performance using the apparatus of the present invention.

Detailed Description

Conventionally, devices and methods for correcting vision correct only central vision (or foveal vision). This practice is based on the knowledge that the fovea (considered the center of vision) is the most sensitive part of the retina in terms of visual acuity and image clarity. The eye will naturally rotate to "fixate" on the visual object of interest (i.e., change the direction of gaze so that the portion of the visual image of most interest is projected to the fovea) to take advantage of the maximum visual acuity available to the fovea. Thus, to date, attention has been focused on improving the final outcome of central or foveal vision when dealing with refractive vision correction. This has led invisibly to the search for improvements in the patient's central vision that excludes imaging of the peripheral retina, often at the expense of peripheral vision. In fact, this lack of interest in imaging peripheral vision also indirectly contributes to the success in the progression of myopia treatment as set forth in the earlier work cited above. Attempts have been made at that time to achieve a treatment that can treat myopia by adjusting peripheral defocus and providing a clear image of central vision at substantially the same time, but these attempts have all failed. Our earlier work overcomes this deficiency in the art. However, in our earlier work, the established goal of slowing or reversing the progression of myopia dictates a particular peripheral defocus or stimulus required, without regard to the peripheral vision state ultimately achieved by the patient. In fact, in many treatments, if central vision must be well-protected, inducing peripheral defocus stimuli can potentially reduce peripheral vision in order to achieve retardation or prevention of myopia progression.

Our current new research results present the possibility and hope for accurate adjustment of peripheral focus to accurate peripheral retinal locations, for achieving substantially simultaneous good central vision and greatly enhanced peripheral vision, thereby achieving good overall vision.

It is currently understood that peripheral refraction may be "ametropic" for an individual (i.e., a condition of improper focus; which includes myopia, hyperopia, or astigmatism and is in contrast to "emmetropia"; emmetropia is accurate in focus location). The peripheral refractive state does not always exactly match the central refractive state. For example, the eye will have a correctly focused central image point (i.e., central refractive normal), but the mid-peripheral image points of the eye may be unfocused (i.e., peripheral refractive error). Any other combination is possible including, but not exclusively, central hyperopia and peripheral hyperopia, central myopia and peripheral emmetropia, etc. The result is that the use of a device that corrects only the central refractive state, such as a conventionally used device, will not (and cannot) correct the peripheral refractive state. For those devices, while central vision is corrected or improved, peripheral vision can be degraded or impaired.

In accordance with embodiments of the present invention, methods and apparatus are disclosed for improving peripheral vision by positioning peripheral image points to a predetermined precise location relative to the retina in accordance with one or more preselected peripheral standard parameters for optimal peripheral vision performance. Embodiments of the present invention contemplate both the process of "finding" the best location and providing a treatment plan, thereby achieving an improvement in peripheral vision.

The principles and basis of the present invention are described in the following sections in conjunction with fig. 1-11. In particular, the optical diagrams (fig. 1-8) illustrate the optical principles associated with the present invention. It should be noted that these graphically depicted eyes are presented in a "simplified eye" fashion (i.e., shown without optical components inside the eye, such as the lens). However, the principles of the present invention may be fully defined by such a simplified optical representation of the eye showing only the anterior refractive surface, the retina and the pupil. Moreover, the positioning of the image points relative to the actual anterior-posterior axis of the retina (i.e., from anterior to posterior closer to the cornea to the retina) is shown exaggerated in these figures, thereby more clearly presenting the concepts encompassed by the present invention.

Figures 1 and 2 are optical illustrations illustrating central refractive error but peripheral refractive error.

In fig. 1, the eye [101] is peripheral myopia, while in fig. 2, the eye [201] is peripheral hyperopia. Central emmetropia is determined from central foci [104] and [204] located on respective fovea [105] and [205 ]. In FIG. 1, the peripheral image point [102] is located in front of the peripheral retina [103] (i.e., in a direction from the retina toward the cornea) due to peripheral myopia. In FIG. 2, the peripheral image point [202] is located behind the peripheral retina [203] (i.e., in a direction away from the cornea from the retina) due to peripheral hyperopia. From conventional vision correction practices, these eyes are considered to not require a refractive correction device, since central vision is already optimal. However, their peripheral vision is not optimal and can be further improved.

Figures 1 and 2 also represent equivalent optical scenarios in which the central vision refractive error has been corrected by conventional corrective devices. In this case, the light rays [106] and [206] entering the eyeball may be considered to be emitted from a conventional optical device not shown. This results in a peripheral residual ametropic condition (peripheral myopia in figure 1 and peripheral hyperopia in figure 2).

It is an object of the present invention to control not only the central imaging position but also one or more peripheral imaging positions. This is illustrated in the examples shown in fig. 3 to 8.

In FIG. 3, the illustrated eye [301] has some degree of central myopia, and deeper-lying peripheral myopia, as seen by the position of central image point [304] and peripheral image point [302] relative to the retina [303 ].

In fig. 4, the eye [301] of fig. 3 has been corrected using a conventional vision correction device [410] that only attempts to correct foveal/foveal vision. Thus, the central image point [404] has been repositioned to the fovea [405 ]. Because such devices typically have a relatively constant refractive power (for central vision correction) across their field of view, refractive correction relative to the central image point also acts on peripheral image points. Thus, the peripheral image point [402] is repositioned to some extent, but not enough to place it on the peripheral retina [303 ]. Thus, the eye is still peripherally myopic (albeit by a lesser amount than the original refractive state) and does not have optimal peripheral vision.

In FIG. 5, the eye [301] of FIG. 3 has been corrected using an apparatus [510] according to an embodiment of the invention. In this device, the central axial power is selected to correct central myopia while the peripheral power is selected to correct peripheral myopia of greater depth. This allows selective positioning of the central image point [504] and peripheral image points [502] relative to the retina [303] and fovea [405] to corrective positions thereby providing optimal central and peripheral visual performance.

Fig. 6 provides another example. In this case, the eye [601] is central hyperopic and the peripheral emmetropia. This is seen by the central image point [604] being behind the fovea [605] and the peripheral image point [602] being near the peripheral retina [603 ].

In this case, the eyeball of FIG. 6 corrected with the conventional vision correction device shown in FIG. 7 would result in good central vision (central image point [704] now located on the retina [605]), but would cause peripheral vision myopia (peripheral image point [702] now located in front of the peripheral retina [603 ]). Thus, peripheral vision is optimal or near optimal prior to correction, and the introduction of conventional optical devices deteriorates peripheral vision.

This situation is addressed by embodiments of the present invention. In fig. 8, a vision correction device [810] in accordance with an embodiment of the invention provides an amount of axial (central) refractive power to correct for central hyperopia of the eye of fig. 6. The peripheral (off-axis) optical power of the device is selected so as not to introduce any change to the imaging position of the periphery, thus maintaining good peripheral vision of the eye. As can be seen, the central image point [804] and the peripheral image point [802] are now located near the fovea [605] and the peripheral retina [603], respectively.

It is an object of the present invention, according to embodiments thereof, to correct and/or preserve not only central focus, but also peripheral vision. For many individuals, the correction and/or preservation can be determined by determining the degree of defocus in the periphery of the eye.

As an alternative to the optical illustration, the above concepts may be represented by numerical symbols. For example, table 1 below sets forth tabulated results representative of the examples of fig. 6-8. Here, it can be seen that the second row is the uncorrected refractive state of the eye, with central hyperopia equal to an amount of +2.50D, and peripheral emmetropia (and often expressed as plano by vision correction practitioners). Conventional devices that correct only the +2.50D central refractive state (and thus the same corrective refractive power for both the center and periphery, as shown in the third row) would change the central refractive state to emmetropia (fourth row), but at the same time result in a near vision state with peripheral vision equal to-2.50D. The device according to embodiments of the present invention will then provide the correct optical power for both the centre and the periphery (as shown in the fifth row). The end result is that both central and peripheral vision is emmetropic (row six).

TABLE 1

	Center (C)	Periphery of
			Uncorrected	+2.50D	Plano
Corrective action of conventional apparatus	+2.50D	+2.50D
			After conventional correction (+2.50D)	Plano	-2.50D
Corrective action of embodiments of the invention	+2.50D	Plano
			After correction (+2.50/Plano)	Plano	Plano

In practice, particularly clinical applications, the prescription (script) of a device according to an embodiment of the invention may be considered as an extension of the conventional vision correction description format. While the above-described device may also be conveniently applied to astigmatic components (i.e., cylindrical power and axis) as understood by the vision correction industry, the principles of the present invention can be briefly illustrated by reference to only the spherical power indications.

In conventional practice, corrective prescription for three diopters of distance vision is recorded

+3.00D

As discussed above, only the refractive state of the fovea is indicated by a single number.

For the indications of the present invention, such +3.00D presbyopia typically has emmetropic peripheral vision, for example, measured at a 30 ° viewing angle, and thus such indications may be:

+3.00D

Plano30°

if more than one peripheral imaging position is deemed beneficial, this indication format can be conveniently extended as follows. For example, it is envisaged that further finding that the eye exhibits-0.75D myopia at 45 viewing angles may indicate to the device of the present invention to improve peripheral vision at 30 and 45 viewing angles, and that the indication may be:

+3.00D

Plano30°

-0.75D45°

it can now be seen that any number of peripheral powers can be specified for correction of any number of peripheral imaging positions. Likewise, by numerically connecting the list of two or more peripheral optical powers, the instructions for the apparatus of the present invention may be specified or constructed as a continuous or partially continuous mathematical function (e.g., polynomial, spline, etc.).

It can also be seen that more complex representations/indications can be found from the additional parameters. For example, if the amount of peripheral defocus in the ocular region is asymmetric; for example, a field of view on the nasal side (i.e. in the direction from eye to nose) is-2.50D 30, and a field of view on the temporal side (i.e. in the direction from eye to nose) is-0.75D 30, then the peripheral power of a device according to embodiments of the invention also needs to be asymmetric to provide control of peripheral vision for both the nasal and temporal fields of view. Similarly, the peripheral imaging position control for vertical and oblique viewing angles along the eye is also considered symmetrically and asymmetrically.

As described above, conventional vision correction focuses on the foveal region. This is an inference based on the recognition that the central region of the retina has the highest retinal cell density and thus the highest visual acuity. It is common practice to neutralize the central refractive error and thereby optimize central visual acuity.

As before, the description of the embodiments has focused on one aspect of the invention, namely correcting peripheral refractive conditions. These embodiments are intended to neutralize peripheral refractive error in addition to correcting a central refractive condition.

However, embodiments of the present invention recognize and utilize certain other aspects of the vision and visual performance found in the peripheral region, such as contrast sensitivity, motion detection, light detection, etc., which may be used as standard parameters. In addition, improvement in peripheral vision in accordance with any one (or combination) of the above standard parameters will in turn benefit the patient in clinically subjective but equally important considerations to the individual (in vision correction, "subjective" refers to an assessment that requires observation or preference of the patient, as opposed to direct measurement without "objective" from patient input), such as subjective vision assessment, or subjective preference for peripheral vision performance, or subjective preference, clarity and acceptability for overall vision performance, etc. Many other subjective performance criteria/parameters of personal clinical importance to a patient are familiar to vision correction practitioners and may be selected as peripheral performance criteria for embodiments of the present invention. According to embodiments of the present invention, these and other parameters in the peripheral defocus sought to be "tuned" by the methods and apparatus of the present invention are characteristic.

Unlike other attempts to adjust peripheral effects, it is now recognized that various aspects or features of peripheral vision (e.g., contrast sensitivity, motion detection sensitivity, etc.) are selectively altered or "tuned" via peripheral vision selective correction through precise optical refractive control and readjusted imaging locations on the periphery of the retina, in accordance with embodiments of the present invention. Furthermore, since the resolution of the central-peripheral and peripheral retina is generally low, the characteristics of the critical spatial frequencies that should be tuned (such as contrast sensitivity, etc.) are believed to be different from the characteristics of the high spatial frequencies that are generally associated with central visual acuity. As a result, it may happen that the best visual performance does not occur when the focus is "ideal" (i.e. when the peripheral refractive error has been neutralized).

In fact, our experimental findings indicate that for some individuals, peripheral defocus is not always the best predictor of peripheral vision. Fig. 9 shows the results of measuring the peripheral contrast sensitivity of three subjects. The measured peripheral contrast sensitivity, indicated as contrast threshold, is shown along the vertical axis (generally, the lower the threshold, the better the visual performance). For these three subjects, peripheral refractive states were first measured and then optically neutralized. Peripheral contrast sensitivity is then measured as the difference between the induced peripheral defocus and their best corrected peripheral refractive state. Thus, along the horizontal axis, the amount of peripheral defocus (i.e., equal to the induced peripheral refractive state) is plotted.

From the curve interpolation in fig. 9 for each tested connected measured data point, it is not necessary to completely neutralize the ambient defocus to achieve optimal contrast sensitivity. Thus, for peripheral correction in patients who meet subjective preference for improved contrast sensitivity, the optimal peripheral power may be slightly "out of focus" relative to the measurement of objective refraction. Many other examples of using other criteria parameters as a guide for optimizing peripheral visual performance are contemplated. The following are a few examples illustrating this principle.

For example, if it is most important to detect horizontal motion in the horizontal plane (e.g., to detect a vehicle driving from a lane into a highway, or to detect lateral airspace while flying an aircraft), then it is more important to sense motion at the sharp vertical edge. Because the eye may have some degree of astigmatism (or myopia or variations due to oblique astigmatism), it may be useful to "tune" the peripheral focus so that the vertical line focus of astigmatism lies on the retina.

Further, while playing sports, key visual objects (e.g., soccer, hockey, baseball, two-way flying saucer, waterfowl, etc.) may have characteristic spatial frequency ranges or bands due to, among other things, their shape, size, and critical distance. In this case, it may be more beneficial to set the peripheral focus to maximize contrast sensitivity for the spatial frequencies of those spatial frequency bands.

Thus, while the peripheral refractive state is a reasonable first order approximation to improve and optimize peripheral visual performance to fully optimize peripheral vision, it may also be necessary to measure and monitor changes in visual performance based additionally on performance criteria parameters selected for the different peripheral controls introduced. That is, the peripheral focus may have to be further "tuned" according to the most important visual tasks of the wearer.

Still further, embodiments of the present invention contemplate correcting or modifying peripheral refraction while maintaining optimal central vision. In such cases, it is considered beneficial to begin to improve or otherwise (as contemplated in accordance with embodiments of the present invention) change the peripheral focus of the ocular device from slightly different than central (e.g., different from a field angle corresponding to a relatively central vision with little to no effective overlap of the projection of the entrance pupil). The process of selecting the appropriate field angle to begin depends on how precisely the peripheral focal points need to be changed, while the individual's "change tolerance" in vision at the center, side-center, and pupil size (and impact on the scholar-kebye effect).

Examples of the present invention

Clinical case 1

Conventional soft contact lenses were worn by 5.00D myopic adult patients. The centre worn diopter (i.e. refractive error measured at the tip of the worn contact lens) of a single eye was found to be-0.21D, indicating that conventional contact lenses accurately correct the patient's central vision. This is also confirmed by the contrast sensitivity measurement back to the central contrast sensitivity threshold of 0.175. However, by measuring the peripheral wearing power of this eye at an angle of 30 ° (requiring the use of the same detection device as used for central refraction measurements, except that the patient is instructed to fix at a target point at the appropriate viewing angle to measure peripheral refraction), the eye is found to have a hyperopia of about + 3.08D. This indicates that the conventional contact lens does not accurately correct for peripheral defocus. In fact, the central refraction of the eye is-5.00 + -0.21 ═ -5.21D myopia, but the periphery of the eye is-5.00 +3.08 ═ -1.92D myopia at 30 degrees field angle. Thus, when a conventional contact lens is worn to correct central-5.00D myopia, a residual amount of hyperopia is improperly introduced into the periphery. This is particularly uncomfortable for those patients who are more accustomed to the visual sensations associated with uncorrected myopic peripheries. The measured contrast sensitivity at this peripheral angle was found to be at the 1.615 contrast threshold (a higher contrast threshold indicates poor visual performance), while the visual acuity measurement at this peripheral angle was found to be 1.242log mar units.

The eye is corrected using a contact lens according to the principles of an embodiment of the present invention. The contact lens has the same central correction (i.e., -5.00D) as a conventional contact lens worn by the patient, but the peripheral power of the lens appears to the eye as-2.00D at about 30 degrees field angle. The peripheral contrast sensitivity of the eye wearing the contact lens of the invention returned to a greatly improved performance of 1.04 (i.e., lower contrast threshold) while peripheral visual acuity was also found to be improved, to 0.975LogMAR units (lower LogMAR units indicate good visual acuity).

This patient also reported a more subjective preference for the quality of vision when wearing the contact lenses of the invention as compared to conventional contact lenses.

The peripheral visual performance of the exemplary eye can be further improved by experimentally testing other contact lenses with slightly different peripheral powers. Using an iterative method, such as a step or binary search method, finding the optimum peripheral refractive power that achieves the best visual performance according to the performance criterion parameters; the standard parameters include peripheral contrast sensitivity, peripheral visual acuity, and overall subjective preference of the patient portion.

The basic concept is exemplified in clinical case 2.

Clinical case 2

A mild myope under 13 years old wearing conventional contact lenses was found to achieve contrast sensitivity thresholds of 0.87 and 0.99 at 30 ° temporal and nasal field angles, respectively. (some eyes are known to have asymmetrical peripheral refractive states; e.g., the nasal visual field is more myopic than the temporal visual field, etc., which results in asymmetrical visual manifestations). Peripheral refraction implies that the peripheral field of view is relatively far-sighted. Thus, a lens according to the principles of the present invention is worn on the eye to test the ability of the lens to improve peripheral contrast sensitivity. This lens introduces an additional +1.50D for the peripheral power at a field angle of 30 °. The resulting contrast sensitivity threshold was improved to 0.59 and 0.91 in the temporal and nasal fields, respectively.

Additional contact lenses according to the principles of the present invention, but with an amount of greater peripheral refractive power, were worn on the eye to assess their effect on peripheral contrast sensitivity. At a peripheral extra power of about +2.50 at an angle of 30 deg., the resulting contrast sensitivity threshold worsens, and the temporal and nasal fields of view return to 0.97 and 1.17 (for an extra peripheral power of about + 2.50D). At a stronger peripheral add power at an angle of about +3.00D at 30 °, the resulting contrast sensitivity threshold is further worsened, with temporal and nasal fields of view of 1.07 and 1.37, respectively. The latter two cases thus revert to a worse peripheral visual performance than conventional contact lenses.

This particular example demonstrates how the correct peripheral optical power using the apparatus of the invention can improve peripheral visual performance (in this case, in the form of contrast sensitivity). This example also further demonstrates how placing a peripheral image in front of the retina with a sufficiently high amount of peripheral add power (as described by the myopia treatment methods in our earlier work) potentially degrades the peripheral visual performance of some individuals.

Clinical case 3

A normally sighted young person was found to have a central contrast sensitivity threshold of 0.31 and a peripheral contrast sensitivity of 0.71 for a temporal field angle of 30 °. The peripheral field of view reveals peripheral refractive results versus myopia. Lenses incorporating an additional-0.50D peripheral power at an angle of field of 30 ° were worn on the eye to test their ability to improve peripheral contrast sensitivity. The resulting contrast sensitivity thresholds were improved to 0.24 and 0.65 for the central and temporal side fields of view, respectively.

Additional contact lenses in accordance with the principles of the present invention, but with an amount of more positive peripheral refractive power, were worn on the eye to assess their effect on peripheral contrast sensitivity. At a peripheral power of about +3.00D at an angle of 30 deg., the resulting contrast sensitivity threshold variation is 0.51 and 1.15 for temporal and nasal fields of view, respectively.

This example demonstrates how peripheral visual performance (in terms of contrast sensitivity) in emmetropic eyes can be further improved or degraded by adjusting the peripheral power of the apparatus of the invention.

Given the foregoing clinical cases, therefore, in one embodiment, one or more standard parameters of peripheral visual performance, such as objective visual optical performance parameters including, for example, contrast sensitivity, visual acuity, motion detection, light detection, etc., are selected as one or more indicators of peripheral vision improvement; or subjective qualitative parameters including, for example, subjective visual quality, visual "normality", peripheral or global visual preferences, visual discomfort, etc. The peripheral refractive action state of the eye is then measured. Estimating from the results a change in peripheral refractive effect required to optimize a standard parameter of peripheral visual performance. This estimation may be performed by first selecting a device with a peripheral refractive effect that substantially neutralizes the peripheral refractive condition of the eye while providing the correct central refractive correction.

If the selected device is proven to provide a sufficient/acceptable level of ambient performance, the device may be given immediately. If improvement is desired, further improvement and optimization of the peripheral visual appearance can be achieved iteratively by applying different incremental peripheral refractive effects to the eye and measuring the response of the standard parameter. After such a progressive optimization iteration, the best correction is selected, or the best result can be interpolated/extrapolated from the results obtained during the iteration.

Because these "trial" lenses do not require optimization or correction of central vision, these trial lenses may be single vision lenses. Furthermore, it may be possible to make a kit or "trial device" consisting of two or more test devices with different amounts of peripheral refractive action to incrementally change the peripheral refractive action on the eye, particularly with the goal of being able to converge rapidly and iteratively to an optimal peripheral description for the patient.

Alternatively to the selection of the use of a peripheral refractive state-based or iterative description method, the description of the peripheral refractive effect of a device according to an embodiment of the invention may be selected by establishing a look-up table relating standard responses to peripheral inflexion states (e.g. after collecting the necessary data from a relational study between the two parameters). From fig. 9 it can be understood how such data for the contrast sensitivity criteria are acquired and compared. In fig. 9, although individual responses to three subjects are shown, the data can be summarized into a "typical" response based on the average of all subjects. In this manner and by collecting data from a large number of trials, a relationship between peripheral refractive state and contrast sensitivity can be constructed, thereby establishing a population response curve. Similar curves can be obtained in the same way for other standard parameters.

As a further alternative to selecting a description of the peripheral refractive effect based on the measured peripheral refractive state, the selection of the device (initial and for dispensing) may be established by simply considering the central refractive state of the eye. Our studies have shown that there is a population trend to correlate central refractive states with peripheral refractive states. In fig. 10, the peripheral refractive states of the same eye at a 30 degree field, the focal-nose side field of view, are depicted along the vertical axis relative to the central refractive state. It can be seen from the figure that there is a strong trend of the correlation of the two refractive states.

Thus, by considering the patient's central refractive error and then referencing the population-averaged relationship between the central refractive error and the selected field angle peripheral refractive error, a suitable apparatus of the invention can be selected for a number of patients to improve peripheral visual performance.

As will be appreciated, relationships similar to fig. 10 can be established at different meridians (e.g., horizontal temporal, horizontal nasal, vertical superior, tilted along the 45 degree meridian, etc.) and different field angles to facilitate an initial selection or appropriate final selection of peripheral refractive effects for the device of the present invention to improve, enhance and optimize peripheral visual performance.

One proposed protocol (shown in fig. 11) is contemplated by embodiments of the present invention, comprising the steps of:

1. a central refractive state of the patient is identified or measured.

2. Peripheral refractive conditions of the patient at one or more peripheral locations are measured.

3. Lenses are selected that will correct the central refraction and also the peripheral refraction.

4. The corrective device is provided to the eye.

5. According to the peripheral visual performance of the patient according to one or more selected standard parameters (e.g., contrast sensitivity, motion detection, light detection, subjective visual quality, subjective overall preference, visual discomfort, etc.).

6. If desired, the iteration from step 4 is started with different peripheral refractive effects until the peripheral performance is appropriate or optimal.

As the vision correction provider will appreciate, while the above protocol is provided, not all of the above steps are necessary depending on the level of optimization of peripheral vision and the desired overall vision. As will be appreciated from the preceding discussion, step 2 of the above process may be replaced by reference to a normal population relationship between the central and peripheral refractive states. Also from the previous discussion, step 3 may be facilitated or refined by reference to the population relationship between the peripheral refractive state and one or more peripheral visual performance criterion parameters.

While conventional vision correction is typically provided for distance viewing (e.g., correction for hyperopic individuals), methods and apparatus according to embodiments of the present invention may also be used to improve or optimize peripheral vision performance at any viewing distance other than distance viewing, as will be appreciated by vision correction practitioners.

While the foregoing discussion has illustrated the enhancement of peripheral visual performance by reference to a single eye, because the visual system is binocular, the present invention also provides for the improvement, enhancement and optimization of peripheral visual performance at different viewing distances for different eyes of an individual. This is particularly useful for e.g. hyperopic individuals or individuals with specific occupational needs (e.g. microscope operators) who can benefit from one eye being "globally" optimized for distance (through the eyepiece of the microscope) and one eye being "globally" optimized for near (for read/write recordings) when they operate the microscope monocular.

According to an embodiment, the present invention contemplates the use of any useful vision correction device that achieves peripheral vision improvement. These devices include lenses, devices and ophthalmic systems such as contact lenses, spectacles, external/internal anterior and posterior chamber intraocular lenses, orthokeratology systems, and refractive corneal surgery (PRK, LASIK, etc.).

The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive, and the scope of the invention is indicated by the appended claims rather than by the foregoing description. And all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

Claims (14)

1. A method for altering peripheral vision, comprising the steps of:

providing an ophthalmic system comprising a predetermined design for achieving at least one peripheral criteria parameter,

controlling the positioning of at least one peripheral image point relative to the retina of the eye to achieve a predetermined effect on said standard parameter;

by ensuring that the predetermined central field of view focus is located on the retina and fovea of the eye, clear central vision is provided substantially simultaneously,

wherein the at least one peripheral criteria parameter comprises contrast sensitivity, photosensitivity, motion detection, or visual evoked potential.

2. The method of claim 1, wherein the at least one peripheral criteria parameter includes improved contrast sensitivity.

3. A method for altering peripheral vision in an eye comprising the steps of:

identifying a central refractive state;

selecting at least one peripheral criteria parameter;

selecting a corrective device to correct the central refraction and selectively correcting the peripheral refraction;

providing the eye with the corrective device; and

measuring peripheral vision performance according to the selected peripheral standard parameters;

wherein the at least one peripheral criteria parameter comprises contrast sensitivity, photosensitivity, motion detection, or visual evoked potential.

4. A method as recited in claim 3, wherein the step of selecting a corrective device includes the additional step of measuring one or more peripheral refractive states to facilitate selection of the corrective device.

5. A method according to claim 3, wherein the step of selecting a correction device comprises the additional step of facilitating selection of the correction device by referencing the response relationship between the central refractive state and the peripheral refractive states with the identified central refractive state to estimate one or more peripheral refractive states.

6. A method according to claim 3, wherein the step of selecting a corrective device comprises the additional step of referencing a response relationship between the central refractive state and the selected peripheral standard parameter with the identified central refractive state to facilitate selection of the corrective device.

7. The method of claim 3, wherein at least one peripheral criteria parameter comprises improved contrast sensitivity.

8. An ophthalmic apparatus, comprising:

a central optical zone, at least one peripheral optical zone, and at least one mixing zone;

the central optical zone providing a predetermined correction factor to provide substantially clear central vision;

wherein the peripheral optical zone provides the predetermined correction factor to control the positioning of at least one peripheral image point to alter or improve visual performance based on one or more peripheral criteria parameters;

wherein the blend zone is located between adjacent central and peripheral optical zones to provide mechanical and geometric continuity between adjacent zones; and

wherein the one or more peripheral criteria parameters include contrast sensitivity, photosensitivity, motion detection, or visual evoked potential.

9. The apparatus of claim 8, wherein the size of the central optical region is approximately greater than the size of the entrance pupil of the eye.

10. The apparatus of claim 8, wherein the one or more peripheral criteria parameters include improved contrast sensitivity.

11. A kit comprising at least two ophthalmic devices:

wherein the ophthalmic devices each comprise a central optical zone, at least one peripheral optical zone, and at least one mixing zone;

wherein the central optical zone provides a predetermined correction factor to provide substantially clear central vision, the peripheral optical zones provide the predetermined correction factor to control the positioning of at least one peripheral image point to change a peripheral standard parameter, and the blend zone is located between adjacent central and peripheral optical zones to provide mechanical and geometric continuity between adjacent zones; and

wherein each ophthalmic device in the kit provides a different predetermined correction factor for controlling the positioning of peripheral image points; and

wherein the peripheral criteria parameters include contrast sensitivity, photosensitivity, motion detection, or visual evoked potential.

12. A method of altering peripheral vision of both eyes of an individual, comprising the steps of:

providing an ophthalmic system for each of the two eyes, the ophthalmic system including a predetermined design for achieving at least one peripheral criteria parameter;

controlling the positioning of the at least one peripheral image point relative to the retina of the eye to achieve a predetermined effect on the standard parameter;

providing clear central vision substantially simultaneously by ensuring that the predetermined central field of view focus is located at the retina and fovea of the eye;

wherein said control of peripheral image point positioning provides different positioning of peripheral image points between said eyes.

13. The method of claim 12, wherein the at least one peripheral criteria parameter comprises contrast sensitivity, photosensitivity, motion detection, or visual evoked potential.

14. The method of claim 12, wherein the at least one peripheral criteria parameter includes improved contrast sensitivity.