Study of stereopsis using a depth sensation detection platform equipped with computer vision technology (DALE3D) / Estudio de estereopsis mediante una plataforma de detección de sensaciones de profundidad equipada con tecnología de visión por ordenador (DALE3D)

Background and objectives: The invention described herein is a prototype based on computer vision technology that measures depth perception and is intended for the early examination of stereopsis. Materials and methods: The prototype (software and hardware) is a depth perception measurement system that consists on: (a) a screen showing stereoscopic models with a guide point that the subject must point to; (b) a camera capturing the distance between the screen and the subject's finger; and (c) a unit for recording, processing and storing the captured measurements. For test validation, the reproducibility and reliability of the platform were calculated by comparing results with standard stereoscopic tests. A demographic study of depth perception by subgroup analysis is shown. Subjective comparison of the different tests was carried out by means of a satisfaction survey. Results: We included 94 subjects, 25 children and 69 adults, with a mean age of 34.2 ± 18.9 years; 36.2 % were men and 63.8 % were women. The DALE3D platform obtained good repeatability with an interclass correlation coefficient (ICC) between 0.94 and 0.87, and coefficient of variation (CV) between 0.1 and 0.26. Threshold determining optimal and suboptimal results was calculated for Randot and DALE3D test. Spearman's correlation coefficient, between thresholds was not statistically significant (p value > 0.05). The test was considered more visually appealing and easier to use by the participants (90 % maximum score). Conclusions: The DALE3D platform is a potentially useful tool for measuring depth perception with optimal reproducibility rates. Its innovative design makes it a more intuitive tool for children than current stereoscopic tests. Nevertheless, further studies will be needed to assess whether the depth perception measured by the DALE3D platform is a sufficiently reliable parameter to assess stereopsis.(AU)

Comparison of Foraging Interactive D-prime and Angular Indication Measurement Stereo with different methods to assess stereopsis.

PURPOSE: Stereopsis is a critical visual function, however clinical stereotests are time-consuming, coarse in resolution, suffer memorization artifacts, poor repeatability, and low agreement with other tests. Foraging Interactive D-prime (FInD) Stereo and Angular Indication Measurement (AIM) Stereo were designed to address these problems. Here, their performance was compared with 2-Alternative-Forced-Choice (2-AFC) paradigms (FInD Stereo only) and clinical tests (Titmus and Randot) in 40 normally-sighted and 5 binocularly impaired participants (FInD Stereo only). METHODS: During FInD tasks, participants indicated which cells in three 4*4 charts of bandpass-filtered targets (1,2,4,8c/° conditions) contained depth, compared with 2-AFC and clinical tests. During the AIM task, participants reported the orientation of depth-defined bars in three 4*4 charts. Stereoscopic disparity was adaptively changed after each chart. Inter-test agreement, repeatability and duration were compared. RESULTS: Test duration was significantly longer for 2-AFC (mean = 317s;79s per condition) than FInD (216s,18s per chart), AIM (179s, 60s per chart), Titmus (66s) or RanDot (97s). Estimates of stereoacuity differed across tests and were higher by a factor of 1.1 for AIM and 1.3 for FInD. No effect of stimulus spatial frequency was found. Agreement among tests was generally low (R2 = 0.001 to 0.24) and was highest between FInD and 2-AFC (R2 = 0.24;p<0.01). Stereoacuity deficits were detected by all tests in binocularly impaired participants. CONCLUSIONS: Agreement among all tests was low. FInD and AIM inter-test agreement was comparable with other methods. FInD Stereo detected stereo deficits and may only require one condition to identify these deficits. AIM and FInD are response-adaptive, self-administrable methods that can estimate stereoacuity reliably within one minute.

Playing three-dimensional video games boosts stereo vision.

Playing two-dimensional video games has been shown to result in improvements in a range of visual and cognitive tasks, and these improvements appear to generalize widely1,2,3,4,5,6. Here we report that young adults with healthy vision, surprisingly, showed a dramatic improvement in stereo vision after playing three-dimensional, but not two-dimensional, video games for a relatively short period of time. Intriguingly, neither group showed any significant improvement in binocular contrast sensitivity. This dissociation suggests that the visual enhancement was specific to genuine stereoscopic processing, not indirectly resulting from enhanced contrast processing, and required engaging in a disparity cue-rich three-dimensional environment.

Risk Factors for Corneal Monochromatic Aberrations and Implications for Multifocal and Extended Depth-of-Focus Intraocular Lens Implantation.

PURPOSE: To discuss factors influencing corneal aberrations that might influence the optical quality after intraocular lens (IOL) implantation. METHODS: PubMed and Scopus were the main resources used to search the medical literature. An extensive search was performed to identify relevant articles concerning factors influencing the level of corneal aberrations as of August 27, 2023. The following keywords were used in various combinations: corneal, aberrations, defocus, astigmatism, spherical aberration, coma, trefoil, quadrafoil, intraocular lens, and IOL. RESULTS: Conclusive evidence is lacking regarding the correlation between age and changes in corneal aberrations. Patients with astigmatism have greater corneal higher-order aberrations than those with minimal astigmatism, particularly concerning trefoil and coma. Increased levels of corneal higher-order aberrations are noted following contact lens wear, in patients with dry eye disease, and with pterygium. Increased higher-order aberrations have been reported following corneal refractive surgery and for 3 months following trabeculectomy; regarding intraocular lens surgery, the results remain controversial. CONCLUSIONS: Several factors influence the level of corneal higher-order aberrations. Multifocal and extended depth-of-focus IOLs can share similarities in their optical properties, and the main difference arises in their design and performance with respect to spherical aberration. Preoperative evaluation is critical for proper IOL choice, particularly in corneas with risk of high levels of aberrations. [J Refract Surg. 2024;40(6):e420-e434.].

Clinical Outcomes of a Toric Enhanced Depth-of-Focus Intraocular Lens Based on the Combination of 4th- and 6th-Order Spherical Aberration.

PURPOSE: To assess the visual and refractive outcomes of patients implanted with a toric extended depth-of-focus (EDOF) intraocular lens (IOL) following cataract surgery. METHODS: A total of 44 eyes implanted with the EDOF LuxSmart toric IOL were evaluated 4 to 6 months postoperatively. The main outcomes measurements evaluated were refractive error, rotational stability, distance, intermediate, and near visual acuities, defocus curve, photopic and mesopic contrast sensitivity, wavefront aberrations, and modulation transfer function, and the Catquest-9SF-questionnaire. RESULTS: The mean postoperative spherical equivalent and cylinder were -0.02 ± 0.26 and -0.17 ± 0.29 diopters (D), respectively. A total of 90.45% and 100% of the eyes had a postoperative spherical equivalent within ±0.50 and ±1.00 D, respectively (this being 93.18% and 100% for the refractive cylinder). The mean rotational stability was 0.61 ± 1.61 degrees. The mean binocular corrected distance visual acuity (CDVA), corrected distance intermediate visual acuity (CDIVA), and corrected distance near visual acuity (CDNVA) were -0.02 ± 0.06, 0.07 ± 0.08, and 0.26 ± 0.09 logMAR, respectively. The CDVA was 20/25 or better in 95.45% of patients, CDIVA was 20/25 or better in 72.73%, and CDNVA was 20/40 or better in 72.73%. The defocus curve showed good visual acuity at distance and intermediate vergences. The contrast sensitivity and optical quality outcomes were good with mean higher order, spherical, and coma aberration values of 0.161 ± 0.155, -0.019 ± 0.048, and 0.080 ± 0.065 µm, respectively. A total of 90.9% of patients were either fairly satisfied or very satisfied with their vision after the surgery, and 77.7% of patients reported no difficulties when reading text in newspapers. CONCLUSIONS: Implantation of the toric pure refractive EDOF technology IOL provides good refractive, optical, and visual quality at different distances, with high levels of patient satisfaction being reported. [J Refract Surg. 2024;40(6):e398-e406.].

[Outcomes of extended depth of focus intraocular lenses implantation]. / Rezul'tat implantatsii intraokulyarnykh linz s rasshirennoi glubinoi fokusa.

Extended depth of focus (EDOF) intraocular lenses (IOLs) are the latest IOL designs. In recent years, several models of EDOF IOLs have become available in Russia, two of which (Tecnis Symfony and Acrysof IQ Vivity) are implanted in our clinic. Comparative studies devoted to the results of implantation of the new EDOF IOLs are rare in the available literature. PURPOSE: This article compares the outcomes of implantation of two EDOF IOLs in patients with presbyopia and/or cataract. MATERIAL AND METHODS: The prospective study included 60 patients (81 eyes) after implantation of EDOF IOL Tecnis Symfony (32 patients, 45 eyes; group 1) or EDOF IOL AcrySof IQ Vivity (28 patients, 36 eyes; group 2). The mean follow-up period was 3.9±1.3 months. RESULTS: All groups showed a significant (p<0.05) increase in uncorrected near visual acuity (UCNVA), intermediate visual acuity (UCIVA), and distance visual acuity (UCDVA) at the maximum follow-up time compared to preoperative values. In group 1, the best corrected near visual acuity (BCNVA) increased from 0.61±0.10 to 0.82±0.16 at the maximum follow-up time, and in group 2 - from 0.58±0.08 to 0.67±0.12 (p>0.05). Both groups showed a significant increase in best corrected intermediate and distance visual acuity (BCIVA and BCDVA) at the maximum follow-up time. The increase in the indicator compared to the preoperative period was not significant in both groups (p>0.05). The frequency of side optical phenomena was low in both groups. No significant differences were found between the groups (p>0.05). CONCLUSION: This study presents a comparative analysis of the results of implantation of two different EDOF IOLs. Both lenses were comparable in most of the studied parameters, including providing good distance and intermediate vision, functional near vision, as well as a low frequency of side optical phenomena. In all cases the patients were satisfied with the results of the surgical intervention.

Stereoscopic artificial compound eyes for spatiotemporal perception in three-dimensional space.

Arthropods' eyes are effective biological vision systems for object tracking and wide field of view because of their structural uniqueness; however, unlike mammalian eyes, they can hardly acquire the depth information of a static object because of their monocular cues. Therefore, most arthropods rely on motion parallax to track the object in three-dimensional (3D) space. Uniquely, the praying mantis (Mantodea) uses both compound structured eyes and a form of stereopsis and is capable of achieving object recognition in 3D space. Here, by mimicking the vision system of the praying mantis using stereoscopically coupled artificial compound eyes, we demonstrated spatiotemporal object sensing and tracking in 3D space with a wide field of view. Furthermore, to achieve a fast response with minimal latency, data storage/transportation, and power consumption, we processed the visual information at the edge of the system using a synaptic device and a federated split learning algorithm. The designed and fabricated stereoscopic artificial compound eye provides energy-efficient and accurate spatiotemporal object sensing and optical flow tracking. It exhibits a root mean square error of 0.3 centimeter, consuming only approximately 4 millijoules for sensing and tracking. These results are more than 400 times lower than conventional complementary metal-oxide semiconductor-based imaging systems. Our biomimetic imager shows the potential of integrating nature's unique design using hardware and software codesigned technology toward capabilities of edge computing and sensing.

Continuous psychophysics shows millisecond-scale visual processing delays are faithfully preserved in movement dynamics.

Image differences between the eyes can cause interocular discrepancies in the speed of visual processing. Millisecond-scale differences in visual processing speed can cause dramatic misperceptions of the depth and three-dimensional direction of moving objects. Here, we develop a monocular and binocular continuous target-tracking psychophysics paradigm that can quantify such tiny differences in visual processing speed. Human observers continuously tracked a target undergoing Brownian motion with a range of luminance levels in each eye. Suitable analyses recover the time course of the visuomotor response in each condition, the dependence of visual processing speed on luminance level, and the temporal evolution of processing differences between the eyes. Importantly, using a direct within-observer comparison, we show that continuous target-tracking and traditional forced-choice psychophysical methods provide estimates of interocular delays that agree on average to within a fraction of a millisecond. Thus, visual processing delays are preserved in the movement dynamics of the hand. Finally, we show analytically, and partially confirm experimentally, that differences between the temporal impulse response functions in the two eyes predict how lateral target motion causes misperceptions of motion in depth and associated tracking responses. Because continuous target tracking can accurately recover millisecond-scale differences in visual processing speed and has multiple advantages over traditional psychophysics, it should facilitate the study of temporal processing in the future.

Evaluation of 3D tablet-based stereoacuity test ASTEROID in children with normal and abnormal visual acuity.

PURPOSE: To assess the utility of 3D, tablet-based, glasses-free Accurate STEReotest (ASTEROID) in children compared with the Titmus test. METHODS: Children aged 5-13 years were enrolled in a single-center, nonrandomized, observational comparison study and analyzed by age (5-7 vs 8-13 years) and visual acuity (20/25 or better in both eyes vs abnormal). Each participant underwent both the ASTEROID and Titmus stereoacuity tests. Stereoacuity was defined as fine (≤60 arcsec), moderate (61-200 arcsec), coarse (201-1199 arcsec), or very coarse to nil (≥1200 arcsec). Agreement between the tests was assessed using a weighted kappa (κ) statistic based on all four categories. RESULTS: A total of 112 children were included: 28 aged 5-7 with normal visual acuity, 30 aged 5-7 with abnormal visual acuity, 34 aged 8-13 with normal visual acuity, and 20 aged 8-13 with abnormal visual acuity. Mean ASTEROID score was 688 ± 533 arcsec (range, 13-1200 arcsec). Agreement between ASTEROID and Titmus test scores for participants overall was moderate (κ = 0.52). By subgroup, agreement was fair for children 5-7 with abnormal visual acuity (κ = 0.31), moderate for children 5-7 with normal visual acuity (κ = 0.47) and children 8-13 with normal visual acuity (κ = 0.42), and substantial for children 8-13 with abnormal visual acuity (κ = 0.76). Where ASTEROID and Titmus score group varied, ASTEROID score was poorer in 94% (47/50) of cases. CONCLUSIONS: ASTEROID is a digital, tablet-based test that evaluates global stereopsis, does not require glasses, and provides a continuum of scores. Among children, ASTEROID has good agreement with the Titmus test; however, it may be more sensitive at detecting stereovision deficits. Further study is necessary to determine which test is more accurate.

Patient-Reported Outcome Measures (PROMs) with Refractive and Diffractive Extended Depth of Focus (EDOF) Intraocular Lenses.

BACKGROUND: Extended depth of focus intraocular lenses (EDOF-IOLs) provide unaided far- and mid-range vision. Refractive IOLs, in contrast to diffractive designs, are associated with a lower depth of focus and absence of dysphotopsia. The aim of this study was to assess spectacle independence for far-range, mid-range, and near-vision activities in patients after implantation of refractive or diffractive EDOF-IOLs using patient-reported outcome measures (PROMs) in a real-world setting. PATIENTS AND METHODS: In 2021 and 2022, all patients in a single center referred for bilateral cataract surgery were assigned to 7 experienced cataract surgeons who either bilaterally implanted only a diffractive EDOF-IOL (Carl Zeiss Meditec AG, AT LARA Jena, Germany, three surgeons) or refractive EDOF-IOL (Johnson & Johnson Vision Inc., Tecnis Eyhance Irvine, California, USA, four surgeons) at the surgeon's discretion, with the aim of bilateral emmetropia. Six months after both cataract surgeries, all patients were contacted by telephone and asked to report their outcomes using a structured questionnaire investigating their spectacle usage for various daily activities and their experience with night glare or halos. Inclusion criteria were a normal postoperative visual potential based on the preoperative examination and completion of the questionnaire regarding postoperative visual experience. RESULTS: Of the patients, 514 underwent bilateral cataract surgery aiming for bilateral emmetropia with the implantation of EDOF-IOLs (422 with Tecnis Eyhance and 92 with AT LARA). A complete questionnaire was obtained from 472 (92%) patients, who were included in the study (393 vs. 79). Comparing Tecnis Eyhance with AT LARA IOL, 54 vs. 57% patients were able to perform most of their daily activities without spectacles, 9 vs. 19% reported not being dependent on spectacles at all, 25 vs. 29% reported using their smartphones without spectacles, 15 vs. 49% patients reported experiencing glares or halos at night, and 1 vs.15% with driving disturbance. Overall, 95 vs. 93% patients described themselves as "satisfied" or "highly satisfied" with their IOL. CONCLUSIONS: With both types of EDOF-IOLs, the majority of patients could perform most of their daily activities without spectacles, except reading, and were highly satisfied with their IOLs. Patients with diffractive Zeiss AT LARA EDOF-IOLs were more likely to accomplish unaided near-range visual tasks; however, they were also at a higher risk of experiencing glares or halos at night.

Quantifying the Relationship Between Unilateral Induced Metamorphopsia and Stereopsis Impairment.

Purpose: To investigate the relationship between unilateral metamorphopsia, characterized by visual distortions in one eye, and impaired stereopsis. Methods: Utilizing both near and distance measurements through advanced testing systems, including 4K smartphones and an active shutter three-dimensional system, we simulated varying degrees of unilateral metamorphopsia in 30 healthy young adults aged between 21 and 29 years. Two types of contour-based stereotest symbols, lines and squares, were developed. Distortions were classified into six distinct patterns, each further divided into eight grades of severity. Participants were tasked with identifying visual targets, and their stereothresholds were determined under different conditions of induced distortion. Stereopsis was measured within a range of 2.9 to 1.0 log arcsec, at 0.2 log arcsec intervals. Stereopsis changes under different distortion scenarios were analyzed using the generalized estimating equations, with a sequential Bonferroni adjustment applied for pairwise comparisons. Results: A direct and quantifiable correlation was observed between the severity of metamorphopsia and reductions in stereopsis. As the degree of visual distortion increased, notably in both frequency and amplitude, there was a corresponding decline in stereopsis. This relationship held true in both near and distance measurements of stereopsis. Statistical analyses further reinforced these findings, highlighting a significant detrimental effect of distortion components on stereoacuity. Conclusions: The findings highlight the clinical significance of understanding the interplay between unilateral metamorphopsia and stereopsis. Early interventions in conditions leading to metamorphopsia might be critical to maintaining optimal stereopsis.

Wearable apparatus for correction of visual alignment under torsional strabismus.

SIGNIFICANCE: A wearable optical apparatus that compensates for eye misalignment (strabismus) to correct for double vision (diplopia) is proposed. In contrast to prism lenses, commonly used to compensate for horizontal and/or vertical misalignment, the proposed approach is able to compensate for any combination of horizontal, vertical, and torsional misalignment. PURPOSE: If the action of the extraocular muscles is compromised (e.g., by nerve damage), a patient may lose their ability to maintain visual alignment, negatively affecting their binocular fusion and stereo depth perception capability. Torsional misalignment cannot be mitigated by standard Fresnel prism lenses. Surgical procedures intended to correct torsional misalignment may be unpredictable. A wearable device able to rectify visual alignment and restore stereo depth perception without surgical intervention could potentially be of great value to people with strabismus. METHODS: We propose a novel lightweight wearable optical device for visual alignment correction. The device comprises two mirrors and a Fresnel prism, arranged in such a way that together they rotationally shift the view seen by the affected eye horizontally, vertically, and torsionally. The extent of the alignment correction on each axis can be arbitrarily adjusted according to the patient's particular misalignment characteristics. RESULTS: The proposed approach was tested by computer simulation, and a prototype device was manufactured. The prototype device was tested by a strabismus patient exhibiting horizontal and torsional misalignment. In these tests, the device was found to function as intended, allowing the patient to enjoy binocular fusion and stereo depth perception while wearing the device for daily activities over a period of several months. CONCLUSIONS: The proposed device is effective in correcting arbitrary horizontal, vertical, and torsional misalignment of the eyes. The results of the initial testing performed are highly encouraging. Future study is warranted to formally assess the effectiveness of the device on multiple test patients.

Stereoscopic slant contrast revisited.

The perceived slant of a stereoscopic surface is altered by the presence of a surrounding surface, a phenomenon termed stereo slant contrast. Previous studies have shown that a slanted surround causes a fronto-parallel surface to appear slanted in the opposite direction, an instance of "bidirectional" contrast. A few studies have examined slant contrast using slanted as opposed to fronto-parallel test surfaces, and these also have shown slant contrast. Here, we use a matching method to examine slant contrast over a wide range of combinations of surround and test slants, one aim being to determine whether stereo slant contrast transfers across opposite directions of test and surround slant. We also examine the effect of the test on the perceived slant of the surround. Test slant contrast was found to be bidirectional in virtually all test-surround combinations and transferred across opposite test and surround slants, with little or no decline in magnitude as the test-surround slant difference approached the limit. There was a weak bidirectional effect of the test slant on the perceived slant of the surround. We consider how our results might be explained by four mechanisms: (a) normalization of stereo slant to vertical; (b) divisive normalization of stereo slant channels in a manner analogous to the tilt illusion; (c) interactions between center and surround disparity-gradient detectors; and (d) uncertainty in slant estimation. We conclude that the third of these (interactions between center and surround disparity-gradient detectors) is the most likely cause of stereo slant contrast.

Extraction of three-dimensional shapes in glaucoma patients in response to monocular depth cues.

PURPOSE: To assess the impact of glaucoma on perceiving three-dimensional (3D) shapes based on monocular depth cues. STUDY DESIGN: Clinical observational study. METHODS: Twenty glaucoma patients, subjected to binocular visual-field sensitivity (binocular-VFS) tests using a Humphrey Visual Field Analyzer, and 20 age-matched healthy volunteers, underwent two tasks: identifying the nearest vertex of a 3D shape using monocular shading (3D-SfS), texture (3D-SfT), or motion (3D-SfM) cues, and distinguishing elementary one-dimensional (1D) features of these cues. The association of the visual-field index (VFI) of binocular-VFS with 3D shape perception in glaucoma patients was also examined. RESULTS: Glaucoma patients demonstrated reduced accuracy in distinguishing 1D luminance brightness and a larger "error-in-depth" between the perceived and actual depths for 3D-SfM and 3D-SfS compared to healthy volunteers. Six glaucoma patients with a 100% VFI for binocular-VFS exhibited a similar error-in-depth to the other fourteen glaucoma patients; they had a larger error-in-depth for 3D-SfM compared to healthy volunteers. No correlation between the error-in-depth values and the VFI values of binocular-VFS was observed. CONCLUSIONS: The 3D shape perception in glaucoma patients varies based on the depth cue's characteristics. Impaired 1D discrimination and larger thresholds for 3D-SfM in glaucoma patients with a 100% VFI for binocular-VFS indicate more pronounced perceptual deficits of lower-level elementary features for 3D-SfS and higher-level visual processing of 3D shapes for 3D-SfM. The effects of the location and degree of binocular visual-field defects on 3D shape perception remain to be elucidated. Our research provides insights into the 3D shape extraction mechanism in glaucoma.

Extended depth of focus IOL in eyes with different axial myopia and targeted refraction.

AIM: To evaluate the objective visual outcomes following implantation of extended depth of focus intraocular lens (EDOF IOL) in individuals with varying axial lengths (AL) and targeted refraction. METHODS: This retrospective study comprised age-matched eyes that underwent implantation of the EDOF IOL. Eyes were categorized based on AL into groups: control group with AL < 26 mm; high myopia group with AL ≥ 26 mm. Each group was then subdivided based on postoperative spherical equivalent (SE). Follow-up at three months included assessment of uncorrected visual acuity at different distances, contrast sensitivity (CS), refractive outcomes, and spectacle independence. RESULTS: Overall, this study included 100 eyes from 100 patients, comprising 50 males (50.00%) and 50 females (50.00%), with 20 eyes in each group. In the control group, the uncorrected distance visual acuity (UDVA) at 5 and 3 m (m) in the - 1.50 to -0.75 group was inferior to that of the - 0.75 to 0.00 group (P = 0.004). Conversely, the uncorrected near visual acuity (UNVA) at 33 cm in the - 1.50 to -0.75 group was superior to that of the - 0.75 to 0.00 group (P = 0.005). Within the high myopia group, the UDVA at 5 and 3 m in the - 2.25 to -1.50 group was worse than in the - 0.75 to 0.00 group (P = 0.009 and 0.008, respectively). However, the UNVA at 33 cm in the - 2.25 to -1.50 group was better than in the - 0.75 to 0.00 group (P = 0.020). No significant differences were observed among the groups for corrected distance visual acuity (CDVA) (P > 0.05). Additionally, in the high myopia group, the CS of the - 2.25 to -1.50 group was lower compared to that of the - 0.75 to 0.00 group (P = 0.017). Among high myopia patients, 90.00% with refraction ranging from - 1.50 to -0.75 reported achieving overall spectacle independence. CONCLUSIONS: Implantation of extended depth of focus intraocular lenses (IOLs) yields satisfactory visual and refractive outcomes in eyes with axial myopia. Among high myopia patients, a refraction ranging from - 1.50 to -0.75 diopters achieves superior visual quality compared to other postoperative myopic diopters.

Peripheral Binocular Imbalance in Anisometropic and Strabismic Amblyopia.

Purpose: Individuals with amblyopia experience central vision deficits, including loss of visual acuity, binocular vision, and stereopsis. In this study, we examine the differences in peripheral binocular imbalance in children with anisometropic amblyopia, strabismic amblyopia, and typical binocular vision to determine if there are systematic patterns of deficits across the visual field. Methods: This prospective cohort study recruited 12 participants with anisometropic amblyopia, 10 with strabismic amblyopia, and 10 typically sighted controls (age range, 5-18 years). Binocular imbalance was tested at 0°, 4°, and 8° eccentricities (4 angular locations each) using band-pass filtered Auckland optotypes (5 cycles per optotype) dichoptically presented with differing contrast to each eye. The interocular contrast ratio was adjusted until the participant reported each optotype with equal frequency. Results: Participants with anisometropic and strabismic amblyopia had a more balanced contrast ratio, or decreased binocular imbalance, at 4° and 8° eccentricities as compared with central vision. Participants with strabismic amblyopia had significantly more binocular imbalance in the periphery as compared with individuals with anisometropic amblyopia or controls. A linear mixed effects model showed a main effect for strabismic amblyopia and eccentricity on binocular imbalance across the visual field. Conclusions: There is evidence of decreased binocularity deficits, or interocular suppression, in the periphery in anisometropic and strabismic amblyopia as compared with controls. Notably, those with strabismic amblyopia exhibited more significant peripheral binocular imbalance. These variations in binocularity across the visual field among different amblyopia subtypes may necessitate tailored approaches for dichoptic treatment.

Toward a theory of perspective perception in pictures.

This paper reviews projection models and their perception in realistic pictures, and proposes hypotheses for three-dimensional (3D) shape and space perception in pictures. In these hypotheses, eye fixations, and foveal vision play a central role. Many past theories and experimental studies focus solely on linear perspective. Yet, these theories fail to explain many important perceptual phenomena, including the effectiveness of nonlinear projections. Indeed, few classical paintings strictly obey linear perspective, nor do the best distortion-avoidance techniques for wide-angle computational photography. The hypotheses here employ a two-stage model for 3D human vision. When viewing a picture, the first stage perceives 3D shape for the current gaze. Each fixation has its own perspective projection, but, owing to the nature of foveal and peripheral vision, shape information is obtained primarily for a small region of the picture around the fixation. As a viewer moves their eyes, the second stage continually integrates some of the per-gaze information into an overall interpretation of a picture. The interpretation need not be geometrically stable or consistent over time. It is argued that this framework could explain many disparate pictorial phenomena, including different projection styles throughout art history and computational photography, while being consistent with the constraints of human 3D vision. The paper reviews open questions and suggests new studies to explore these hypotheses.

Quality of vision clinical outcomes for a new fully-refractive extended depth of focus Intraocular Lens.

BACKGROUND/OBJECTIVE: To evaluate the visual performance of a purely refractive extended depth of focus (EDF) intraocular lens (IOL). SUBJECTS/METHODS: A prospective, multi-center, randomized, subject/evaluator-masked study. Subjects were bilaterally implanted with the EDF test (Model ZEN00V, N = 60) or an enhanced monofocal control (Model ICB00, N = 57) IOL. Monocular corrected distance (CDVA), intermediate (DCIVA), near acuities (DCNVA) and patient reported visual symptoms were evaluated at the 6-month visit. Monocular mesopic contrast sensitivity (CS) and depth of focus (DOF) testing were assessed at 3 months. RESULTS: CDVA (Mean ± SD) was -0.06 ± 0.08 for test and -0.05 ± 0.08 logMAR for control groups. DCIVA was 0.13 ± 0.08 for test and 0.18 ± 0.14 logMAR for control groups (p = 0.0127). DCNVA was 0.37 ± 0.10 for test and 0.43 ± 0.16 logMAR for control groups (p = 0.0137). Test lens was statistically superior for intermediate and near. Overall, 91.7% (halos), 95.0% (starbursts) and 95.0% (glare) of test lens patients reported that they did not experience, were not bothered, or were slightly bothered by specific visual symptoms, compared to 98.2%, 100% and 96.5% in the control group. The DOF range over which monocular visual acuity was 0.20 logMAR or better was -1.6 D for the test lens. Mesopic CS was comparable between both groups, falling within 0.11 log units for all measured cycles per degree with and without glare. CONCLUSION: The EDF IOL demonstrated extended range of vision and statistically superior intermediate and near performance compared to the monofocal IOL. Distance visual acuity, contrast sensitivity and dysphotopsia profile were similar to the monofocal IOL.