Humans can see in exquisite detail despite the fact that the eyes' optics can only focus light at a single wavelength at a time. It remains an open question what wavelength is brought into best focus by the human eye. Here, we investigate this question. We used a custom optical apparatus to measure the eye's focusing response (accommodation) to a range of stimuli with different wavelength compositions. We then developed a biologically informed model of the measured responses. Conventional wisdom holds that accommodation works to maximize visual acuity, but our findings suggest otherwise. Rather, our results support alternative lines of evidence that accommodation is guided by chromatic mechanisms that maximize signal quality in a color-opponent channel. Our results challenge prevailing views of oculomotor control and can inform therapeutic interventions for slowing the development and progression of myopia.

It has been known for more than 220 years that the image quality of the human eye is significantly degraded by chromatic aberrations. Recently, it was shown experimentally that correcting chromatic aberrations results in a 0.2- to 0.8-line improvement in visual acuity. Here we ask, is this expected? We developed tools that enable simulations of the optical impact of physiologically relevant amounts of chromatic aberration in real human eyes and combined these with tools that compute the visual acuity of an ideal observer. This allows us to characterize the theoretical impact of chromatic aberration correction on visual acuity. Results indicate a substantive improvement of 0.4- to 2-lines in ideal observer visual acuity with chromatic aberration correction. Ideal observer thresholds benefit significantly more from correction of longitudinal than correction of transverse chromatic aberration. Finally, improvements in ideal observer visual acuity are greater for subjects with less monochromatic aberration, such that subjects with better baseline optical quality benefit most from correction of chromatic aberrations.

We assessed the effect of a contact lens that filters short-wavelength (SW) visible light on color appearance. These effects were modeled and measured by direct comparison to a clear contact lens. Sixty-one subjects were enrolled, and 58 completed as cohort; 31 were 18 to 39 years old (mean ± SD, 29.6 ± 5.6), 27 were 40 to 65 years old (50.1 ± 8.1). A double-masked contralateral design was used; participants randomly wore a SW-filtering contact lens on one eye and a clear control lens on the other eye. Subjects then mixed three primaries (including a short-wave primary, strongly within the absorbance of the test lens) until a perceived perfect neutral white was achieved with each eye. Color appearance was quantified using chromaticity coordinates measured with a spectral radiometer within a custom-built tricolorimeter. Color vision in natural scenes was simulated using hyperspectral images and cone fundamentals based on a standard observer. Overall, the chromaticity coordinates of matches that were set using the SW-filtering contact lens (n = 58; x = 0.345, y = 0.325, u′ = 0.222, v′ = 0.470) and clear contact lens (n = 58; x = 0.344, y = 0.325, u′ = 0.223, v′ = 0.471) were not significantly different, regardless of age group. Simulations indicated that, for natural scenes, the SW-filtering contact lens that was evaluated changes L/(L+M) and S/(L+M) chromatic contrast by no more than −1.4% to +1.1% and −36.9% to +5.0%, respectively. Tricolorimetry was used to measure color appearance in subjects wearing a SW-filtering lens in one eye and a clear lens in the other, and the results indicate that imparting a subtle tint to a contact lens, as in the SW-filtering lens that was evaluated, does not alter color appearance for younger or older subjects. A model of color vision predicted little effect of the lens on chromatic contrast for natural scenes.

We describe a system-the Binocular Varichrome and Accommodation Measurement System-that can be used to measure and correct the eye's longitudinal and transverse chromatic aberration (LCA and TCA) and to perform vision tests with custom corrections. We used the system to investigate how LCA and TCA affect visual performance. Specifically, we studied the effects of LCA and TCA on visual acuity, contrast sensitivity, and chromostereopsis. LCA exhibited inter subject variability but followed expected trends compared with previous reports. TCA at the fovea was variable between individuals but with a tendency for the shift at shorter wavelengths to be more temporalward in the visual field in each eye. We found that TCA was generally greater when LCA was corrected. For visual acuity, we found that a measurable benefit was realized only with both LCA and TCA correction unless the TCA was low. For contrast sensitivity, we found that the best sensitivity to a 10-cycle/degree polychromatic grating was attained when LCA and TCA were corrected. Finally, we found that the primary cause of chromostereopsis is the TCA of the eyes.

As humans look around the environment, the crystalline lens inside the eye changes optical power to bring retinal images into focus. This visuomotor response is called accommodation. For a given accommodative state, light at only one wavelength can be in focus because the eye contains significant chromatic aberration. We examined how the visual system weights different wavelengths for focusing polychromatic stimuli, especially those with peaks at more than one wavelength. With an autorefractor, we continuously measured human accommodative responses (at 30 Hz) to stimuli comprising various mixtures of short- and long-wavelength content. In a series of trials, seven human observers viewed a three-letter word stimulus spanning 1.5° (24 arcmins per letter) against a black background on an AMOLED display for seven seconds. The optical distance of the screen was varied using a focus-adjustable lens. Halfway through the trial, the stimulus underwent a step change in optical distance (±0.75, 1.00, or 1.50 diopters). Simultaneously, the color of the stimulus changed. Accommodative responses for each subject were analyzed with nested descriptive models, including a color-free model, a weighted-averaging model, and a color-switching model. The results show that stimulus color significantly influences the dynamic accommodative response, and that long wavelengths influence the response more than short wavelengths, even when their luminance is the same.

Purpose: The purpose of this study is to compare the binocular visual perception of participants wearing multifocal contact lenses and these same lens designs viewed through a temporal multiplexing visual simulator.Methods: Visual performance and perceived visual quality at various distances were obtained in 37 participants wearing soft M-CLs and through the SimVis Gekko programmed with the same lenses. In a pilot study (n = 10) visual performance was measured in terms of LogMAR visual acuity (VA) at far (4 m), intermediate (64 cm) and near (40 cm) distances and through-focus VA (TFVA) curves with the simulated M-CLs. In the follow-up study (n = 27), LogMAR VA at far, intermediate and near distances were measured both with the actual and simulated M-CLs. Perceived visual quality was measured in both studies using the Multifocal Acceptance Score (MAS-2EV), and a Participants Reported Outcomes Vision questionnaire. Differences between the metrics obtained with simulated and actual lenses were obtained.Results: Both actual and simulated M-CLs increased depth-of-focus by a similar amount. Mean LogMAR VA differences with actual and simulated M-CLs ranged between 4 and 6 letters (0.08 +/- 0.01, 0.12 +/- 0.01 and 0.10 +/- 0.01, for far, intermediate and near distances, respectively). MAS-2EV average score differences with actual and simulated M-CLs ranged between-1.00 and + 4.25. Average MAS-2EV scores were not correlated significantly with VA. However, MAS-2EV (average and individual scores) were highly correlated to visual quality questionnaire responses (p < 0.005).Conclusions: A simultaneous vision simulator accurately represented vision with M-CLs both VA at various distances and perceived visual quality, as measured in a clinical setting. The MAS-2EV metric accurately captured participant reported outcomes of standard vision questionnaires. The combination of SimVis Gekko and MAS-2EV has the potential to largely reduce chair time in M-CLs fitting.

Wavefront metrics such as root mean squared error provide excellent descriptions of optical quality but the connection to visual performance is not directly interpretable from the wavefront alone. Converting to visual acuity (VA) would provide a more accessible assessment of the effect of ocular wavefront. In this study, multiple measurements of wavefront and pupil diameter were acquired at 1 cd/m2 using the iDesign 1.3 (Johnson and Johnson Surgical Vision) in 552 eyes of 293 subjects. Uncorrected (UC) and best corrected (BC) VA were measured at 4m for each eye at 100 cd/m2 . VA was estimated using a neural contrast sensitivity function (NCSF) weighted modulation transfer function (MTF). To estimate BCVA, sphere and astigmatism terms were nulled. For each subject, classification was performed using random forest considering estimated VA, age, measured pupil diameter, manifest refraction spherical equivalent, manifest refraction cylinder and gender. Across all measurements, predicted differed from measured UCVA by -0.11 and BCVA by +1.6 (-10logMAR). The NCSF-based model predicts population mean VA to within approximately 2-lines but cannot predict an individual’s VA well, supporting the notion that other factors need to be considered to obtain more accurate estimates of VA. Classification with the random forest approach improved the accuracy of estimates of an individual subject’s VA; approximately 95% of the estimates match the measured VA.

Purpose: As multifocal contact lenses (MCLs) expand as a solution for presbyopia correction, a better understanding of their optical and visual performance becomes essential. Also, providing subjects with the experience of multifocal vision before contact lens fitting becomes critical, both to systematically test different multifocal designs and to optimize selection in the clinic. In this study, we evaluated the ability of a simultaneous vision visual simulator (SimVis) to represent MCLs. Methods: Through focus (TF) optical and visual quality with a center-near aspheric MCL (low, medium and high near adds) were measured using a multichannel polychromatic Adaptive Optics visual simulator equipped with double-pass, SimVis (temporal multiplexing), and psychophysical channels to allow measurements on-bench and in vivo. On bench TF optical quality of SimVis-simulated MCLs was obtained from double-pass (DP) images and images of an E-stimulus using artificial eyes. Ten presbyopic subjects were fitted with the MCL. Visual acuity (VA) and DP retinal images were measured TF in a 4.00 D range with the MCL on eye, and through SimVis simulations of the same MCLs on the same subjects. Results: TF optical (on bench and in vivo) and visual (in vivo) quality measurements captured the expected broadening of the curves with increasing add. Root mean square difference between real and SimVis-simulated lens was 0.031/0.025 (low add), 0.025/0.015 (medium add), 0.019/0.011 (high add), for TF DP and TF LogMAR VA, respectively. A shape similarity metric shows high statistical values (lag κ = 0), rho = 0.811/0.895 (low add), 0.792/0.944 (medium add), and 0.861/0.915 (high add) for TF DP/LogMAR VA, respectively. Conclusions: MCLs theoretically and effectively expand the depth of focus. A novel simulator, SimVis, captured the through-focus optical and visual performance of the MCL in most of the subjects. Visual simulators allow subjects to experience vision with multifocal lenses prior to testing them on-eye. Translational Relevance: Simultaneous visual simulators allow subjects to experience multifocal vision non-invasively. We demonstrated equivalency between real multifocal contact lenses and SimVis-simulated lenses. The results suggest that SimVis is a suitable technique to aid selection of presbyopic corrections in the contactology practice.

optional): Provide a 50-200 word description of your work that non-scientists can understand. Describe the big picture and the implications of your findings, not the study itself and the associated details. Trend in Glistening density in Acrylic Intraocular Lenses and its relation to straylight performance AuthorBlock: Marrie van der Mooren, Steven Safran, Henk A. Weeber, Patricia Piers Johnson & Johnson Vision, Groningen, Netherlands; Capital Health System, New Jersey, United States; New Jersey Surgery Center, New Jersey, United States; DisclosureBlock: Marrie van der Mooren, AMO Groningen BV Code E (Employment), Steven Safran, Capital Health System Code E (Employment), New Jersey Surgery Center Code E (Employment), Robert Wood Johnson University Code E (Employment), Johnson & Johnson Vision Code C (Consultant), Henk A. Weeber, AMO Groningen BV Code E (Employment), Patricia Piers, AMO Groningen BV Code E (Employment) Purpose The purpose of this study was to evaluate trends in glistening density in acrylic intraocular lenses (IOLs) and its relation to straylight performanceMethods Ten recently produced lenses of three acrylic IOL materials A, B and C were used for testing. All IOLs were immersed in a 0.9% saline solution. Glistening density and stray light performance were measured before and after one temperature cycle from room temperature to 35 degrees C for 15 hours and back to room temperature. Glistening density was determined using Image J to analyze darkfield microscopy images. The Miyata grading scale was used to classify the glistening density as mild, moderate and severe. Glistening density data were compared to historic data for the same IOL materials. The stray light performance was evaluated in white light for a 4mm pupil and visual angles up to 22 degrees. The straylight levels were compared to a reference level of a 20-year-old healthy crystalline lens. The maximum straylight parameter was correlated with glistening density by means of regression analysis.Results The in-vitro applied temperature cycle appears representative for invivo material performance. For material A there is variability in glistening density ranging from 25 to 257 microvacuoles/mm. There were two IOLs in the severe glistening grade, five in the moderate group and three in the mild group. For material B and C all glistenings were in the mild group. The glistening density findings for all IOL materials continue to be of the same order of magnitude as historically reported for the last 7 years. For material A there is a variability in straylight levels. After the temperature cycle, seven out of ten IOLs had significant elevated straylight values. These correlated with all IOLs in the moderate or severe glistening group. Glistening density and straylight performance are highly correlated (R=0.95) using the maximum straylight parameter.Conclusions Glistening density and straylight performance are highly correlated. The majority of ten recent manufactured and tested IOLs from material A continue to show significant level of glistenings and elevated straylight levels.Layman Abstract (optional): Provide a 50-200 word description of your work that non-scientists can understand. Describe the big picture and the implications of your findings, not the study itself and the associated details. Contrast sensitivity safety limits for IOLs risk of false negative and false positive conclusions AuthorBlock: Robert Rosen, Carmen Canovas, Stanley Bentow, Patricia Piers Johnson & Johnson Vision, Groningen, Netherlands; DisclosureBlock: Robert Rosen, Johnson & Johnson Vision Code E (Employment), Carmen Canovas, Johnson & Johnson Vision Code E (Employment), Stanley Bentow, Johnson & Johnson Vision Code E (Employment), Patricia Piers, Johnson & Johnson Vision Code E (Employment)

Purpose: To evaluate the differences in intraocular lens (IOL) injectors and to assess the effect of IOL insertion on injector tips and eyes after cataract surgery in a rabbit model. Setting: Ophthalmic Biophysics Center, Bascom Palmer Eye Institute, Department of Ophthalmology, University of Miami Miller School of Medicine, Miami, Florida, USA. Design: Experimental study. Methods: A modified optical comparator was used to measure the tips of 13 IOL injector models to determine the perimeter, tip angle, and cone angle of each. Injectors were analyzed before and after IOL insertion. Surgery was performed on rabbits with 71 IOL injectors of 13 models, and custom gauges were used to determine the incision size before and after surgery. Results: The injector dimensions varied by model; tip diameter, tip angle, and cone angle ranged from 1.44 to 2.12 mm, 29.7 to 66.5 degrees and 0.6 to 10.8 degrees, respectively. The incision size through which surgery was successfully performed also varied by injector model; the initial incision sizes ranged from 2.0 to 2.63 mm. For all injectors, there was wound enlargement after IOL insertion that ranged from a 0.1 to 0.65 mm increase in incision length. Conclusions: The dimensions and injection systems varied with each IOL injector. All injectors led to postoperative wound stretch after IOL insertion, with no final incision measuring less than 2.0 mm. These findings suggest that the clear cornea incision should have a width corresponding to the injector diameter. (C) 2018 ASCRS and ESCRS