Vision and Color Fall Data Blast: Session I

Thursday, October 7, 12:00 – 14:00 ET // Register here

This event has already occurred. You can watch a recording here.

Presenters:

• Mitochondrial distribution in the outer plexiform layer of human retina - Does it correlate with reflectivity in OCT? presented by Deepayan Kar, University of Alabama at Birmingham

• A generative adversarial deep neural network to translate between ocular imaging modalities while maintaining anatomical fidelity presented by Sharif Amit Kamran, University of Nevada, Reno

• Towards clinically friendly optoretinography (ORG) using 100 kHz swept-source OCT without adaptive optics (AO) presented by Kari V. Vienola, University of California Davis

• FInD Color Detection and Discrimination in adults with and without color vision deficits: Preliminary results presented by Jingyi He, Northeastern University

• A Multi-Modal Visual Assessment System For Monitoring Spaceflight Associated Neuro-Ocular Syndrome (SANS) During Long Duration Spaceflight presented by Joshua Ong, University of Pittsburgh School of Medicine

• Wavefront analysis testing of protective eyewear presented by Emmanuel Alabi, ICS Laboratories

• Negative dysphotopsia evaluation using individualized eye models presented by Mihai State, Johnson & Johnson Vision

• The effect of spherical defocus on vergence and diplopia in adults and children presented by Clara Mestre, Indiana University

• Adaptation to Prominent Monocular Metamorphopsia using Binocular Suppression presented by Nasif Zaman, University of Nevada, Reno

• What limits the spatial resolution of artificial vision in epiretinal implant patients? presented by Ezgi Irmak Yucel, University of Washington

• Effects of Aging on Speech-in-Noise Discrimination presented by Amy Morris, University of Nevada, Reno

• Larger ON-pathway deficits in rod-dominated disease than cone-dominated disease presented by Amithavikram R Hathibelagal, Brien Holden Institute of Optometry and Vision Sciences

• Effect of Spots versus Gratings on Non-Cardinal Color Perception: Experiment 2 presented by Isaac Temores, Wabash College

Moderators:

• Jessica I. W. Morgan, University of Pennsylvania

• Kimberly Meier, University of Washington

Each data blast session feature a series of short talks followed by lots of time for questions and discussion. This data blast is being hosted by the Vision and Color Technical Division and the Fall Vision Meeting Planning Committee.

Abstracts:

Mitochondrial distribution in the outer plexiform layer of human retina - Does it correlate with reflectivity in OCT?

Presenter: Deepayan Kar, Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA

Co-authors: Yeon Jin Kim, Department of Biological Structure, University of Washington, Seattle, WA, USA; Orin Packer, Department of Biological Structure, University of Washington, Seattle, WA, USA; Department of Biological Structure, University of Washington, Seattle, WA, USA, Department of Biological Structure, University of Washington, Seattle, WA, USA; Dennis M Dacey, Department of Biological Structure, University of Washington, Seattle, WA, USA; Christine A Curcio, Department of Ophthalmology and Visual Sciences, School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA

Mitochondria are organelles essential for cellular metabolism that also contribute reflectivity to optical coherence tomography (OCT) via Mie scattering. To find reflectivity sources, we assessed mitochondrial distribution of outer plexiform layer (OPL) using comprehensive volume electron microscopy.

Parafoveal retina of a 21-year-old male donor was subject to serial block-face scanning electron microscopy in 5x5x50 nm3 voxels. A convolutional neural network (U-Net) was used to train and generate a deep learning model from manually annotated mitochondria ground truth (Dragonfly 2020.1, Object Research Systems). Using this model, mitochondrial volume and occupancy were calculated as a function of retinal depth and plotted as a longitudinal profile.

Photoreceptor terminals contained clusters of ovoid mitochondria. Dendrites of bipolar neurons exhibited long and slender mitochondria. The OPL mitochondrial distribution had three layers of higher density (photoreceptor terminals, bipolar/ horizontal processes, neuropil at the border of inner nuclear layer) interleaved by two bands of lower mitochondrial occupancy (8.5-13.8%). Mitochondria occupied <1% of the Henle fiber. Automated segmentation yielded exceptional performance vs ground truth (Dice coefficient=0.96).

Evidence of multilaminar distribution of mitochondria in the OPL support hypothesis of a subcellular origin of OCT reflectivity bands. Correlative studies using AO-OCT is currently under ongoing investigation.

Funding acknowledgement: Funded by NIH R01EY028282.

A generative adversarial deep neural network to translate between ocular imaging modalities while maintaining anatomical fidelity

Presenter: Sharif Amit Kamran, Department of Computer Science and Engineering, University of Nevada, Reno, USA

Co-authors: Khondker Fariha Hossain, Department of Computer Science and Engineering, University of Nevada, Reno, USA; Alireza Tavakkoli, Department of Computer Science and Engineering, University of Nevada, Reno, USA; Department of Computer Science and Engineering, University of Nevada, Reno, USA, Department of Computer Science and Engineering, University of Nevada, Reno, USA; Joshua Ong, School of Medicine, University of Pittsburg, Pittsburg, PA, USA; Stewart Lee Zuckerbrod, Houston Eye Associates, Houston, TX

Certain ocular imaging procedures such as fluoresceine angiography (FA) are invasive with potential for adverse side effects, while others such as funduscopy are non-invasive and safe for the patient. However, effective diagnosis of ophthalmic conditions requires multiple modalities of data and a potential need for invasive procedures. In this study, we propose a novel conditional generative adversarial network (GAN) capable of simultaneously synthesizing FA images from fundus photographs while predicting retinal degeneration. The proposed system addresses the problem of imaging retinal vasculature in a non-invasive manner while utilizing the cross-modality images to predict the existence of retinal abnormalities. One of the major contributions of the proposed work is the introduction of a semi-supervised approach in training the network to overcome the problem of data dependency from which traditional deep learning architectures suffer. Our experiments confirm that the proposed architecture outperforms state-of-the-art generative networks for image synthesis across imaging modalities. In particular, we show that there is a statistically significant difference (p<.0001) between our method and the state-of-the-art in structural accuracy of the translated images. Moreover, our results confirm that the proposed vision transformers generalize quite well on out-of-distribution data sets for retinal disease prediction, a problem faced by many traditional deep networks.

Funding acknowledgement: This material is based upon work supported by the National Aeronautics and Space Administration under Grant No. 80NSSC20K1831.

Towards clinically friendly optoretinography (ORG) using 100 kHz swept-source OCT without adaptive optics (AO)

Presenter: Kari V. Vienola, Department of Ophthalmology and Vision Science, University of California Davis, USA

Co-authors: Robert J. Zawadzki, Department of Ophthalmology and Vision Science, University of California Davis, USA; EyePod Small Animal Ocular Imaging Laboratory, Department of Cell Biology and Human Anatomy, University of California Davis, USA; Ravi S. Jonnal, Department of Ophthalmology and Vision Science, University of California Davis, USA; Department of Ophthalmology and Vision Science, University of California Davis, USA, Department of Ophthalmology and Vision Science, University of California Davis, USA

Optoretinography measures the stimulus-evoked response of the photoreceptors using light. Current systems use adaptive optics (AO) to obtain cellular-level resolution and fast volume acquisitions, to be able to monitor a single cone’s response with sufficient sampling over time. The systems are complex to operate and therefore are not ideal in the clinical setting, where ease-of-use and high throughput are desirable. Here, we set out to explore if a less complex research-grade imaging system without AO could detect light-evoked changes in the retina when stimulus is applied. The imaging system uses 100 kHz swept source for OCT and tracking laser scanning ophthalmoscope is coupled into the sample arm for active eye-tracking. This provides a correction signal for the OCT to minimize spurious phase noise from eye motion. The stimulus is done with 555 nm LED (single flash and 10 Hz flicker) during OCT imaging. Obviously, the resolution is not the same without AO and signals are a collective response from tens of photoreceptors resulting in measurements of phase shift between scattering speckle fields rather than well-defined single reflections from within a photoreceptor. Improper eye tracking can also negatively affect phase-sensitive imaging needed to observe ORG signals. The ability to observe any stimulus-evoked responses using standard OCT would make optoretinography more accessible to study human vision as well as novel functional biomarkers of retinal diseases.

Funding acknowledgement: UC Davis Eye Center Startup Funds and partially by NIH Grants R00-EY-026068, R01-EY-026556 and R01-EY-031098.

FInD Color Detection and Discrimination in adults with and without color vision deficits: Preliminary results

Presenter: Jingyi He, Department of Psychology, Northeastern University, USA

Co-authors: Anna Boruta, Department of Psychology, Northeastern University, USA; Peter J. Bex, Department of Psychology, Northeastern University, USA; Department of Psychology, Northeastern University, USA, Department of Psychology, Northeastern University, USA; Jan Skerswetat, Department of Psychology, Northeastern University, USA

Color vision deficits are important biomarkers, however, existing tests (e.g., Hardy-Rand-Rittler (HRR) & Farnsworth-Munsell 100 hue test (FM100)) are insensitive and time consuming to administer. FInD is a validated computer-based, generalisable, rapid, self-administered paradigm. We describe FInD Color Detection & FInD Color Discrimination and compare performance against HRR & FM100 tests in 9 color-typical and 4 atypical observers. Chromatic stimuli were presented on a luminance-gamma and cone-isolating calibrated display in 3 charts, each containing 4×4 cells. Each cell contained 1 (detection) or 2 (discrimination) gaussian chromatic patches in 8 Hz luminance noise. Observers reported whether a stimulus was present or whether the 2 stimuli were different in color, respectively. D’ was calculated for short, medium or long wavelength-isolating stimuli (detection) or for hue differences in HSV space, centered on the 3 primary and 3 confusion axes at 50% and 100% saturation (discrimination). Detection and Discrimination thresholds for atypical observers were higher than for typical observers, with selective elevation of detection and discrimination thresholds corresponding to classic color deficits. FInD Color Detection & Discrimination tests rapidly and easily identify chromatic sensitivity deficits along the visual pathways and may provide a valuable diagnostic tool.

Funding acknowledgement: This work is supported by NIH Grant R01 EY029713. FInD is provisionally patented & owned by Northeastern University, USA. JS & PJB are founders of PerZeption Inc.

A Multi-Modal Visual Assessment System For Monitoring Spaceflight Associated Neuro-Ocular Syndrome (SANS) During Long Duration Spaceflight

Presenter: Joshua Ong, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States

Co-authors: Nasif Zaman, Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, Nevada, United States; Sharif Amit Kamran, Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, Nevada, United States; Ethan Waisberg, University College Dublin School of Medicine, Belfield, Dublin, Ireland; Alireza Tavakkoli, PhD, Human-Machine Perception Laboratory, Department of Computer Science and Engineering, University of Nevada, Reno, Reno, Nevada, United States; Andrew G. Lee, MD, Department of Ophthalmology, Blanton Eye Institute, Houston Methodist Hospital, Houston, Texas, United States. Center for Space Medicine, Baylor College of Medicine, Houston, Texas, United States. The Houston Methodist Research Institute, Houston Methodist Hospital, Houston, Texas, United States. Departments of Ophthalmology, Neurology, and Neurosurgery, Weill Cornell Medicine, New York, New York, United States. Department of Ophthalmology, University of Texas Medical Branch, Galveston, Texas, United States. University of Texas MD Anderson Cancer Center, Houston, Texas, United States. Texas A&M College of Medicine, Texas, United States. Department of Ophthalmology, The University of Iowa Hospitals and Clinics, Iowa City, Iowa, United States; Michael Webster, PhD, Department of Psychology, University of Nevada, Reno, United States. Visual Perception Laboratory, University of Nevada, Reno, United States

Spaceflight Associated Neuro-Ocular Syndrome (SANS) refers to a unique collection of neuro-ophthalmic clinical and imaging findings that are observed in astronauts during long duration spaceflight. These findings include optic disc edema, posterior globe flattening, retinal nerve layer fiber thickening, optic nerve sheath distension, and hyperopic shift. SANS currently serves as a large barrier to deep space exploration; however, the exact pathophysiology is still being investigated. While in-flight imaging exists on the International Space Station, there are limitations to constant monitoring. To efficiently document the subtle changes that occur in SANS, NASA has funded the development of a head-mounted display, multi-modal visual assessment system; this novel device integrates visual acuity, visual field, contrast sensitivity, and metamorphopsia data (indirect indications) with known terrestrial neuro-ophthalmic imaging (direct indications) from astronauts and terrestrial analogs. By mapping these two indications, this visual assessment device will provide rapid in-flight monitoring of SANS symptoms and provide tools for the terrestrial development of countermeasures. We are in the process of beginning a pilot study of this multi-modal visual assessment device in healthy subjects to investigate the validity and reliability of this novel technology. This foundational study will compare the system with standard vision assessments utilized in clinical practice.

Funding acknowledgement: This research was funded by NASA Grant 80NSSC20K1831 titled: A Non-intrusive Ocular Monitoring Framework to Model Ocular Structure and Functional Changes due to Long-term Spaceflight.

Wavefront analysis testing of protective eyewear

Presenter: Emmanuel Alabi, Research Department, ICS Laboratories, USA

Co-author: Tyler Harris, Research Department, ICS Laboratories, USA

Purpose: The optical testing requirements of plano-protective eyewear in numerous national standards rely on subjective evaluation methods that are negatively impacted by factors such as accommodation, depth of focus, field of view and optical system resolving power differences. The aim of this study was to develop an objective method for testing the optical requirements of plano-protective eyewear. Method:A Shack-Hartmann wavefront sensor and 542 nm collimated laser setup was used to build a Wavefront Analysis Optical Tester (WFAOT). The WFAOT was used to measure the refractive power of 9 calibration lenses and the left oculars of 36 military plano-protective eyewear. Subjective testing of the same samples was done using the telescope method described by American National Standard Institute (ANSI) Z87.1. A dependent t-test was used to evaluate the relationship between protective eyewear refractive powers before and after a two-week interval.SPSS 16 for Windows was used for all statistical analysis.

Results: The spherical powers of the verification lenses measured with WFAOT and ANSI Z87.1 telescope approach are shown in Table 1. There was no difference in refractive powers of the same protective eyewear measured before (M=-0.010, SD=0.018) and after (M=-0.009, SD=0.019) a two-week interval; t(35)= -0.466, p = 0.644. Conclusion:WFAOT is a refractive power measurement method comparable to the telescope approach proposed by ANSI Z87.1.

Funding acknowledgement: Funding provided by the Combat Capabilities Development Command

Negative dysphotopsia evaluation using individualized eye models

Presenter: Mihai State, R&D, Surgical, Johnson & Johnson Vision, Groningen, Netherlands

Co-authors: Stefan Palkovits, Vienna Institute for Research in Ocular Surgery, A Karl Landsteiner Institute, Hanusch Hospital, Vienna, Austria; Aixa Alarcon, R&D, Surgical, Johnson & Johnson Vision, Groningen, Netherlands; R&D, Surgical, Johnson & Johnson Vision, Groningen, Netherlands, R&D, Surgical, Johnson & Johnson Vision, Groningen, Netherlands; Oliver Findl, Vienna Institute for Research in Ocular Surgery, A Karl Landsteiner Institute, Hanusch Hospital, Vienna, Austria; Carmen Canovas, R&D, Surgical, Johnson & Johnson Vision, Groningen, Netherlands; Patricia A. Piers, R&D, Surgical, Johnson & Johnson Vision, Groningen, Netherlands

Building on our previously communicated results, the current study evaluates the predictive ability of individualized eye models to localize negative dysphotopsia (ND) in the peripheral field of view (PFoV)

In a prospective study conducted at Hanusch Hospital, Vienna, Austria, post-operative biometrical data were acquired from five patients implanted with monofocal IOLs and with ND complaints. A Harms tangent screen subjective method was used to localize in PFoV the perceived shadow (HvF). For computing theoretical retinal irradiance maps, individualized Liou-Brennan (non)-sequential eye models were generated using the acquired biometrical data.

Mean axial length was 22.83 (21.05 – 24.80) mm, mean IOL power 24.4 (20.5 – 30.0) D, mean IOL tilt -1.86 (-6.21 – 2.96) degrees and mean decentration 0.16 (-0.27 – 0.44) mm. Average residual astigmatism difference between theoretical and measured data was 0.49 (0.02 – 0.97) D. Aligned with HvF data, the irradiance maps localized ND in the peripheral visual field up to 85 degrees.

Previously presented theoretical results evidenced that in identical biometrical conditions, IOLs from different manufacturers with similar mechanical platforms but different optic edge designs are characterized by comparable ND profiles with the peripheral location of the shadows between 69 and 76 degrees. Further expanding the utilization of these eye models, the current results demonstrate their clinical relevance in terms of PFoV localization of ND.

The effect of spherical defocus on vergence and diplopia in adults and children

Presenter: Clara Mestre, School of Optometry, Indiana University, USA

Co-authors: Sonisha Neupane, School of Optometry, Indiana University, USA; Deborah Giaschi, Department of Ophthalmology and Visual Sciences, University of British Columbia, Canada; Department of Ophthalmology and Visual Sciences, University of British Columbia, Canada, Department of Ophthalmology and Visual Sciences, University of British Columbia, Canada; Laurie M. Wilcox, Centre for Vision Research, York University, Canada; T. Rowan Candy, School of Optometry, Indiana University, USA

Anisometropic children (with unequal refractive error in the two eyes) are at risk for strabismus or amblyopia. We simulated unilateral and bilateral spherical defocus to clarify the link between anisometropia, vergence eye movements and the perception of single vision. Adults (N=20, 15-51 yrs) and typically developing children (N=9, 5-8 yrs) viewed a dichoptic cartoon character presented in the fixation plane. Step changes in disparity of between 0 and 8 deg were introduced for 320 ms, followed by a blank screen. Vergence responses were recorded with an Eyelink 1000 and subjects reported whether they perceived a single (fused) or double (diplopic) character. Spherical defocus from 0.5 to 4D was applied to one or both eyes’ stimuli using convolution of the point spread function for the subject’s pupil size. Open loop vergence amplitude was used to estimate the reflex response (without feedback). For no defocus, open loop vergence peaked at +/-2 deg disparity with amplitudes of 0.29 deg convergence and -0.44 deg divergence for adults, and 0.56 deg and -0.46 deg for children. Bilateral defocus had no effect on this reflex response; however, 4D unilateral defocus significantly reduced vergence amplitudes in both age groups with no corresponding change in diplopia thresholds. Our results confirm that anisometropic blur is particularly disruptive to reflex vergence responses, which could limit the accurate realignment of the eyes and lead to atypical binocular development.

Funding acknowledgement: The project was supported by R01 EY014460 (TRC) and a EY019008 (P30) to Indiana University.

Adaptation to Prominent Monocular Metamorphopsia using Binocular Suppression

Presenter: Nasif Zaman, Department of Computer Science, University of Nevada, Reno, USA

Co-authors: Joshua Ong, University of Pittsburgh School of Medicine, Pittsburgh, United States; Alireza Tavakkoli, Department of Computer Science, University of Nevada, Reno, USA; Department of Computer Science, University of Nevada, Reno, USA, Department of Computer Science, University of Nevada, Reno, USA; Stewart Zuckerbrod, Houston Eye Associates, Houston, TX, USA; Michael Webster, Department of Psychology, University of Nevada, Reno, USA

45.1% of AMD patients perceive visual distortion or metamorphopsia in at least one of their eyes. These distortions pose severe impediment to reading, face recognition and visual search. Adaptation to these dysfunctions are generally preceded by development of significant visual loss. In this study we investigate how different levels of suppression accelerate this adaptation by simulating central, paracentral and cecocentral metamorphopsia monocularly, and then suppressing the resulting perception by overlaying a scotoma (completely black circle). Distortions with the same physical features are more noticeable when they are located centrally. Our results strongly confirm that binocular interactions allow for the complete suppression. Furthermore, we show that milder suppressions (50% area) takes considerably longer to adapt to, and the prominence of the scotoma remains relatively stable over time. The results further show that if the metamorphopsia is in the dominant eye, the effect of binocular compensation is diminished noticeably. Cecocentral metamorphopsia were generally adapted to with even mild suppression as their proximity to the physiological blind spot makes them particularly vulnerable to suppression.

Funding acknowledgement: This material is based upon work supported by the national aeronautics and space administration under grant no. 80NSSC20K1831

What limits the spatial resolution of artificial vision in epiretinal implant patients?

Presenter: Ezgi Irmak Yücel, Department of Psychology, University of Washington, USA

Co-authors: Michael Beyeler, Computer Science, UC Santa Barbara; Roksana Sadeghi, Biomedical Engineering, Johns Hopkins University, USA; Biomedical Engineering, Johns Hopkins University, USA, Biomedical Engineering, Johns Hopkins University, USA; Ariel Rokem, Department of Psychology, University of Washington, USA; Ione Fine, Department of Psychology, University of Washington, USA; Arathy Kartha, Lions Vision Research and Rehabilitation Center; Gislin Dagnelie, Lions Vision Research and Rehabilitation Center

Introduction: Retinal implants provide artificial vision to blind individuals through electrically stimulating remaining non-photoreceptor retinal cells. For epiretinal implants, placed over the ganglion cell layer, individual electrodes produce elongated ‘streaks’ due to the unselective stimulation of underlying ganglion axons (Beyeler, 2019). Here, to examine whether these axonal streaks explain the poor spatial acuity of prosthetic patients, we measured two-point discrimination performance in three patients implanted with an Argus 2 epiretinal implant (Second Sight Medical Products Inc). Methods: On each trial two electrodes were simultaneously stimulated (0.45 um pulse width, 6-20 Hz pulse train, 250-500ms duration, current amplitude 2x threshold). Participants verbally reported the number of distinct percepts they saw. Results: A regression analysis found that current amplitude, physical distance, distance along the axon, and distance between axons all played a significant role in determining whether participants saw one or two percepts. Conclusions: Participants were less likely to see two distinct percepts when electrodes were physically close or lay close to the same axon bundle. Electrodes with high stimulation thresholds were also less likely to produce distinct percepts. Thus electrode pairs can merge into a single percept when (1) when current fields overlap, (2) their current fields stimulate the same axonal bundle, or (3) the elongated percepts overlap.

Funding acknowledgement: UWIN, NIH

Effects of Aging on Speech-in-Noise Discrimination

Presenter: Amy Morris, Department of Psychology, University of Nevada, Reno, USA

Co-authors: Rakteesud Bamrungyat, Department of Psychology, University of Nevada, Reno, USA; Alexandra N. Scurry, Department of Psychology, University of Nevada, Reno, USA; Department of Psychology, University of Nevada, Reno, USA, Department of Psychology, University of Nevada, Reno, USA; Aaron Seitz, Department of Psychology, University of California, Riverside, USA; Frederick Gallun, Oregon Hearing Research Center, Oregon Health & Science University, USA; Fang Jiang, Department of Psychology, University of Nevada, Reno, USA

The ability to discriminate speech in the presence of background noise decreases with age. The current study examined the effects of noise type and spatial separation between the target and masking speech on speech-in-noise (SiN) discrimination in older (22) and young (25) adults. Using Portable Automated Rapid Testing software implemented on an iPad, participants were asked to separate target speech from either interfering speech (informational masking) or ‘garbled speech’ that contained similar spectro-temporal aspects of sound, but no informational meaning (energetic masking) for three spatial separations (0°, 6°, and 45°). In addition, spectro-temporal modulation (STM) sensitivity, binaural sensitivity, and notched-noise masking thresholds were measured. Overall, older adults showed worse SiN performance compared to young controls for both types of masking at most of the spatial separations. In contrast to their worse sensitivity for binaural detection and notched-noise masking, older adults showed intact STM sensitivity. These findings add knowledge of how aging affects SiN discrimination and provide insight into training programs aimed at improving older adults’ SiN performance.

Funding acknowledgement: P20 GM103650

Larger ON-pathway deficits in rod-dominated disease than cone-dominated disease

Presenter: Amithavikram R Hathibelagal, Brien Holden Institute of Optometry and Vision Sciences, Prof Brien Holden Eye Research Center, Hyderabad, India

Co-authors: Phuntsok Bhutia, Brien Holden Institute of Optometry and Vision Sciences, Prof Brien Holden Eye Research Center, Hyderabad, India; Mritunjoy Das, Brien Holden Institute of Optometry and Vision Sciences, Prof Brien Holden Eye Research Center, Hyderabad, India; Brien Holden Institute of Optometry and Vision Sciences, Prof Brien Holden Eye Research Center, Hyderabad, India, Brien Holden Institute of Optometry and Vision Sciences, Prof Brien Holden Eye Research Center, Hyderabad, India; Helna Babu, Brien Holden Institute of Optometry and Vision Sciences, Prof Brien Holden Eye Research Center, Hyderabad, India; Shonraj Balle GaneshRao, Department of Optometry, Manipal College of Health Professions, Manipal Academy of Higher Education (MAHE), Manipal, Karnataka, India

Purpose: ON-pathway deficits are associated with rod system dysfunction. Therefore, ON pathway function can potentially act as a surrogate marker of the rod system. Here, we have used a tablet-based application (iOS) called ‘EyeSpeed’ to assess the ON and OFF pathway deficits in patients with known retinal diseases.

Methods: 26 patients (19male, 7 female) participated in the study. The patients were diagnosed with either rod-dominated disease [n=14; retinitis pigmentosa (12), rod monochromatism (2)] or cone-dominated disease [n = 12; Stargardt’s disease (5) or cone dystrophy (7)] based on the fundus findings, history and/or electroretinographic findings. The participants were aged between 10- 46 years. The inclusion criteria were that near vision was N24 or better and absence of any other ocular disease. The participants task to identify number of black / white targets embedded in a binary noisy background. Outcome variables are reaction time, accuracy and performance index [accuracy*(1/reaction time)].

Results: The mean difference in reaction times (dark - light) for rod-dominated disease [Mean (SEM): -1.94s (0.43) was significantly higher than cone-dominated disease [ [-0.65s (0.23)]; unpaired t-test, p=0.019]. However, mean differences between dark and light targets in accuracy and performance index were not significantly different between the two groups.

Conclusions: ON pathway deficits in rod-dominated disease is prominent compared to the OFF-pathway deficits.

Effect of Spots versus Gratings on Non-Cardinal Color Perception: Experiment 2

Presenter: Isaac Temores, Department of Psychology, Wabash College, USA

Co-authors: Alexander Naylor, Department of Psychology, Wabash College, USA; Karen L. Gunther, Department of Psychology, Wabash College, USA; Department of Psychology, Wabash College, USA, Department of Psychology, Wabash College, USA

The lateral geniculate nucleus (LGN) processes cardinal colors but not non-cardinal, while non-cardinal color perception occurs in the visual cortex. As LGN receptive fields are circular, spot stimuli are processed better in the LGN, whereas grating stimuli are processed exclusively in the cortex, where receptive fields are elongated. We thus tested whether gratings better reveal non-cardinal mechanisms. Stoughton et al. (2012) tested this question in the isoluminance plane in macaques, and Gegenfurtner & Kiper (1992) in the red-green/luminance plane in humans. We tested all three color planes, all in humans. The current experiment is an extension of Rodriguez, Dunigan, Powell & Gunther (OSA FVM 2018), testing a larger number of directions in color space. In each color plane, three participants performed noise masking with stimuli in 8 or 12 directions in color space, presented in four masks (two cardinal, two 45 deg non-cardinal). Our data support the hypothesis that gratings better reveal non-cardinal mechanisms than spots do. The data are particularly strong in the tritan/luminance plane, the color plane where this has not yet been tested.

Funding acknowledgement: NSF BCS-1753808