Effect of Individualized Ocular Refraction Customization Spectacle Lens Wear on Visual Performance in Myopic Chinese Children.

Purpose: Individualized ocular refraction customization (IORC) lenses can be individually adjusted depending on the initial relative peripheral refraction to determine the myopic defocus (MD). We aimed to compare visual performance of children wearing IORC lenses with different amounts of MD to determine whether higher MD resulted in greater visual compromise. Methods: This study included 184 myopic children aged eight to 12 years, and 172 completed the trial. The participants were randomly assigned to wear IORC lenses with low (IORC-L, 2.50 D), medium (IORC-M, 3.50 D), or high (IORC-H, 4.50 D) MD or single-vision spectacle lenses (SVL). Distance and near best-corrected visual acuity (BCVA), contrast sensitivity function (CSF) and questionnaires were evaluated at baseline and after six and 12 months. Results: CSF over all frequencies and distance and near BCVA were not affected by lens design (all P > 0.05). The SVL group outperformed the three IORC lens groups in terms of ghosting images at baseline, and IORC-H and IORC-M groups outperformed IORC-L group (all P < 0.001); however, no differences were observed at the six- or 12-month visit. There were no significant differences among the four groups for any other subjective variables at any of the follow-up visits regarding vision clarity, vision stability, eyestrain, dizziness, headache, or overall vision satisfaction (all P > 0.05). Conclusions: The IORC lenses with an actual MD of 4.50 D provided acceptable objective and subjective visual performance and were well tolerated by children. Translational Relevance: IORC lenses with an actual MD of 4.50 D provided acceptable visual performance.

What does visual snow look like? Quantification by matching a simulation.

The primary symptom of visual snow syndrome (VSS) is the unremitting perception of small, flickering dots covering the visual field. VSS is a serious but poorly understood condition that can interfere with daily tasks. Several studies have provided qualitative data about the appearance of visual snow, but methods to quantify the symptom are lacking. Here, we developed a task in which participants with VSS adjusted parameters of simulated visual snow on a computer monitor until the simulation matched their internal visual snow. On each trial, participants (n = 31 with VSS) modified the size, density, update speed, and contrast of the simulation. Participants' settings were highly reliable across trials (intraclass correlation coefficients > 0.89), and they reported that the task was effective at stimulating their visual snow. On average, visual snow was very small (less than 2 arcmin in diameter), updated quickly (mean temporal frequency = 18.2 Hz), had low density (mean snow elements vs. background = 2.87%), and had low contrast (average root mean square contrast = 2.56%). Our task provided a quantitative assessment of visual snow percepts, which may help individuals with VSS communicate their experience to others, facilitate assessment of treatment efficacy, and further our understanding of the trajectory of symptoms, as well as the neural origins of VSS.

A paradigm for characterizing motion misperception in people with typical vision and low vision.

PURPOSE: We aimed to develop a paradigm that can efficiently characterize motion percepts in people with low vision and compare their responses with well-known misperceptions made by people with typical vision when targets are hard to see. METHODS: We recruited a small cohort of individuals with reduced acuity and contrast sensitivity (n = 5) as well as a comparison cohort with typical vision (n = 5) to complete a psychophysical study. Study participants were asked to judge the motion direction of a tilted rhombus that was either high or low contrast. In a series of trials, the rhombus oscillated vertically, horizontally, or diagonally. Participants indicated the perceived motion direction using a number wheel with 12 possible directions, and statistical tests were used to examine response biases. RESULTS: All participants with typical vision showed systematic misperceptions well predicted by a Bayesian inference model. Specifically, their perception of vertical or horizontal motion was biased toward directions orthogonal to the long axis of the rhombus. They had larger biases for hard-to-see (low contrast) stimuli. Two participants with low vision had a similar bias, but with no difference between high- and low-contrast stimuli. The other participants with low vision were unbiased in their percepts or biased in the opposite direction. CONCLUSIONS: Our results suggest that some people with low vision may misperceive motion in a systematic way similar to people with typical vision. However, we observed large individual differences. Future work will aim to uncover reasons for such differences and identify aspects of vision that predict susceptibility.

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.

Evaluating integration of letter fragments through contrast and spatially targeted masking.

Four experiments were conducted to gain a better understanding of the visual mechanisms related to how integration of partial shape cues provides for recognition of the full shape. In each experiment, letters formed as outline contours were displayed as a sequence of adjacent segments (fragments), each visible during a 17-ms time frame. The first experiment varied the contrast of the fragments. There were substantial individual differences in contrast sensitivity, so stimulus displays in the masking experiments that followed were calibrated to the sensitivity of each participant. Masks were displayed either as patterns that filled the entire screen (full field) or as successive strips that were sliced from the pattern, each strip lying across the location of the letter fragment that had been shown a moment before. Contrast of masks were varied to be lighter or darker than the letter fragments. Full-field masks, whether light or dark, provided relatively little impairment of recognition, as was the case for mask strips that were lighter than the letter fragments. However, dark strip masks proved to be very effective, with the degree of recognition impairment becoming larger as mask contrast was increased. A final experiment found the strip masks to be most effective when they overlapped the location where the letter fragments had been shown a moment before. They became progressively less effective with increased spatial separation from that location. Results are discussed with extensive reference to potential brain mechanisms for integrating shape cues.

Higher-contrast images are better remembered during naturalistic encoding.

It is unclear whether memory for images of poorer visibility (as low contrast or small size) will be lower due to weak signals elicited in early visual processing stages, or perhaps better since their processing may entail top-down processes (as effort and attention) associated with deeper encoding. We have recently shown that during naturalistic encoding (free viewing without task-related modulations), for image sizes between 3°-24°, bigger images stimulating more visual system processing resources at early processing stages are better remembered. Similar to size, higher contrast leads to higher activity in early visual processing. Therefore, here we hypothesized that during naturalistic encoding, at critical visibility ranges, higher contrast images will lead to higher signal-to-noise ratio and better signal quality flowing downstream and will thus be better remembered. Indeed, we found that during naturalistic encoding higher contrast images were remembered better than lower contrast ones (~ 15% higher accuracy, ~ 1.58 times better) for images at 7.5-60 RMS contrast range. Although image contrast and size modulate early visual processing very differently, our results further substantiate that at poor visibility ranges, during naturalistic non-instructed visual behavior, physical image dimensions (contributing to image visibility) impact image memory.

Visual and Refractive Outcomes After Bi-aspheric Trifocal Toric Diffractive Intraocular Lens Implantation.

PURPOSE: To assess clinical outcomes after cataract surgery with bilateral implantation of a new bi-aspheric diffractive intraocular lens (IOL). METHODS: Thirty patients underwent bilateral implantation of the Asqelio Trifocal Toric IOL (AST Products, Inc) and were evaluated 3 months postoperatively. Main outcomes included refractive error, photopic monocular and binocular uncorrected and corrected distance (UDVA, CDVA), intermediate (UIVA, CDIVA) at 60 cm, and near (UNVA, CDNVA) at 40 cm visual acuities. Mesopic monocular and binocular CDNVA were also measured. Defocus curves, binocular contrast sensitivity under photopic and mesopic conditions with and without glare and rotational stability were determined. Patients completed Catquest-9SF and visual symptoms questionnaires. RESULTS: Average values of binocular photopic CDVA, CDIVA, and CDNVA, and mesopic CDNVA were -0.04 ± 0.06, 0.02 ± 0.08, 0.02 ± 0.07, and 0.22 ± 0.11 logMAR, respectively. All patients achieved cumulative CDVA ⩾ 20/25, and CDIVA and CDNVA of 20/32 or better. Binocular depth of focus was approximately 3.25 diopters (D). Mean postoperative spherical equivalent was -0.08 ± 0.26 D, with 95% of eyes within ±0.50 D. Mean postoperative refractive cylinder was -0.22 ± 0.27 D, with 91.67% of eyes within 0.50 D or less, respectively. IOL rotation averaged 0.25 ± 0.65 degrees, all eyes having rotation of less than 5 degrees. Contrast sensitivity was within or above normal levels under photopic and mesopic conditions, with or without glare, except for 12 cpd under mesopic conditions with glare. Questionnaire responses indicated 96.67% of patients were satisfied or very satisfied with postoperative vision, and 80.00% to 96.67% reported no difficulty in different daily activities. CONCLUSIONS: The Asqelio Trifocal Toric IOL demonstrated favorable outcomes, providing excellent visual performance at all distances, precise refractive results, and remarkable rotational stability. Patients reported high satisfaction levels and minimal difficulty in daily activities. [J Refract Surg. 2024;40(6):e407-e419.].

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.].

Biomarker evidence of early vision and rod energy-linked pathophysiology benefits from very low dose DMSO in 5xFAD mice.

Here, we test whether early visual and OCT rod energy-linked biomarkers indicating pathophysiology in nicotinamide nucleotide transhydrogenase (Nnt)-null 5xFAD mice also occur in Nnt-intact 5xFAD mice and whether these biomarkers can be pharmacologically treated. Four-month-old wild-type or 5xFAD C57BL/6 substrains with either a null (B6J) Nnt or intact Nnt gene (B6NTac) and 5xFAD B6J mice treated for one month with either R-carvedilol + vehicle or only vehicle (0.01% DMSO) were studied. The contrast sensitivity (CS), external limiting membrane-retinal pigment epithelium (ELM-RPE) thickness (a proxy for low pH-triggered water removal), profile shape of the hyperreflective band just posterior to the ELM (i.e., the mitochondrial configuration within photoreceptors per aspect ratio [MCP/AR]), and retinal laminar thickness were measured. Both wild-type substrains showed similar visual performance indices and dark-evoked ELM-RPE contraction. The lack of a light-dark change in B6NTac MCP/AR, unlike in B6J mice, is consistent with relatively greater mitochondrial efficiency. 5xFAD B6J mice, but not 5xFAD B6NTac mice, showed lower-than-WT CS. Light-adapted 5xFAD substrains both showed abnormal ELM-RPE contraction and greater-than-WT MCP/AR contraction. The inner retina and superior outer retina were thinner. Treating 5xFAD B6J mice with R-carvedilol + DMSO or DMSO alone corrected CS and ELM-RPE contraction but not supernormal MCP/AR contraction or laminar thinning. These results provide biomarker evidence for prodromal photoreceptor mitochondrial dysfunction/oxidative stress/oxidative damage, which is unrelated to visual performance, as well as the presence of the Nnt gene. This pathophysiology is druggable in 5xFAD mice.

Evaluation of contrast sensitivity in patients with congenital red-green color vision deficiency.

PURPOSE: To evaluate mesopic and photopic contrast sensitivity in patients with congenital red-green color vision deficiency regarding with and without glare conditions and to compare these findings with age- and gender-matched healthy controls with normal color vision. METHODS: Patients with congenital red-green color vision deficiency and age- and gender-matched healthy controls were included in this cross-sectional comparative study. Contrast sensitivity measurements were taken from all subjects in 4 different conditions; binocular mesopic-without glare, mesopic-with glare, photopic-without glare, photopic-with glare, and the results were compared. RESULTS: Twenty one patients with color vision deficiency (13 deuteranopic, 8 protanopic) and 22 age- and gender-matched healthy controls were included in the study. The mean age was 35.2 ± 13.5 years in the protan group, 30.6 ± 7.7 years in the deutan group, 32.0 ± 8.8 years in the control group, and there was no significant difference in age between the groups (P > 0.05). The mean mesopic and photopic contrast sensitivity values of the groups at all spatial frequencies (1.5, 3, 6, 12, 18 cpd) were not statistically significant when evaluated by the multifactor repeated measures test of ANOVA to evaluate the effect of light conditions (with and without glare) (P > .05). CONCLUSION: Mesopic and photopic contrast sensitivity values of patients with congenital red-green color vision deficiency were similar to healthy controls regarding with and without glare conditions.

Associations Between Visual Functions and Severity Gradings, Corneal Scatter, or Higher-Order Aberrations in Fuchs Endothelial Corneal Dystrophy.

Purpose: The purpose of this study was to investigate the associations between visual function and severity grading, corneal scatter, or higher-order aberrations (HOAs) in patients with Fuchs endothelial corneal dystrophy (FECD). Methods: This observational case series study included 49 eyes of 27 patients with FECD and 10 eyes of 10 healthy individuals. We evaluated corrected distance visual acuity (CDVA) using Landolt-C and Early Treatment Diabetic Retinopathy Study charts and contrast sensitivity using the CSV-1000E chart and CSV-1000RN letter chart. We analyzed the associations between visual function and explanatory variables, including age, modified Krachmer grade, central corneal thickness (CCT), anterior segment optical coherence tomography (AS-OCT)-based grade, HOAs, intraocular straylight, and corneal densitometry. We additionally conducted receiver operating characteristic (ROC) analysis to identify the corneal densitometry thresholds for decreased visual function. Results: There were significant associations between visual function and the modified Krachmer grade, CCT, AS-OCT-based grade, HOAs, intraocular straylight, and corneal densitometry. A modified Krachmer grade ≥ 3 was identified as a threshold for decreased visual function. Multivariate analysis showed that corneal densitometry was significantly associated with all visual function parameters, and HOAs were significantly associated with CDVA but not with contrast sensitivity. ROC analysis revealed that corneal densitometry of the posterior layer at 0 to 2 mm ≥ 10 grayscale units (GSU), was identified as a threshold for decreased visual function. Conclusions: HOAs, forward and backward light scatter affected visual function, with backward light scatter being the most influential. In patients with FECD, modified Krachmer grade ≥ 3 and corneal densitometry ≥ 10 GSU were thresholds for visual disturbance.

Hazard Perception in Visually Impaired Drivers Who Use Bioptic Telescopes.

Purpose: Bioptic telescopic spectacles can allow individuals with central vision impairment to obtain or maintain driving privileges. The purpose of this study was to (1) compare hazard perception ability among bioptic drivers and traditionally licensed controls, (2) assess the impact of bioptic telescopic spectacles on hazard perception in drivers with vision impairment, and (3) analyze the relationships among vision and hazard detection in bioptic drivers. Methods: Visual acuity, contrast sensitivity, and visual field were measured for each participant. All drivers completed the Driving Habits Questionnaire. Hazard perception testing was conducted using commercially available first-person video driving clips. Subjects signaled when they could first identify a traffic hazard requiring a change of speed or direction. Bioptic drivers were tested with and without their bioptic telescopes in alternating blocks. Hazard detection times for each clip were converted to z-scores, converted back to seconds using the average response time across all videos, and then compared among conditions. Results: Twenty-one bioptic drivers and 21 normally sighted controls participated in the study. The hazard response time of bioptic drivers was improved when able to use the telescope (5.4 ± 1.4 seconds vs 6.3 ± 1.8 seconds without telescope); however, it remained significantly longer than for controls (4.0 ± 1.4 seconds). Poorer visual acuity, contrast sensitivity, and superior visual field sensitivity loss were related to longer hazard response times. Conclusions: Drivers with central vision loss had improved hazard response times with the use of bioptic telescopic spectacles, although their responses were still slower than normally sighted control drivers. Translational Relevance: The use of a bioptic telescope by licensed, visually impaired drivers improves their hazard detection speed on a video-based task, lending support to their use on the road.

Peripheral myopic defocus signal affects the efficiency of visual information processing in myopic children.

PURPOSE: Spectacle lenses with peripheral lenslets have shown promise for myopia control by providing peripheral myopic defocus signals. Here, we aimed to investigate the impact of prolonged exposure (>6 months) to peripheral myopic defocus on visual information processing in myopic children. METHODS: The study included 30 myopic children who habitually wore spectacle lenses with highly aspherical lenslets (HAL group) and 34 children who habitually wore single-vision (SV group) spectacles. The quick contrast sensitivity function (qCSF) was used to measure contrast sensitivity (CS) under conditions of no or high noise. Both groups were tested with HAL and SV lenses. The perceptual template model was utilised to fit the contrast sensitivity function (CSF) and determine differences in information processing efficiency through internal additive noise ( N add ) and perceptual template gain (ß). RESULTS: The areas under the log CSF in the SV group were significantly higher than for the HAL group in both zero-noise conditions with the SV test lens (p = 0.03) and high-noise conditions with the HAL test lens (p = 0.02). For 2 cycle per degree (cpd) stimuli, ß was significantly higher in the SV group with the HAL test lens than in the HAL group (p = 0.02), while there was a trend towards a significant difference in ß for 6 cpd stimuli (p = 0.07). However, there were no significant differences in N add between the two groups, with or without noise interference. CONCLUSION: The reduced CS observed in myopic children wearing HAL lenses for 6 months or more may be due to decreased ß. This suggests that prolonged use of spectacle lenses with peripheral myopic defocus signals may compromise the central visual system's ability to process additional external noise, resulting in decreased efficiency in visual information processing.

Primate retina trades single-photon detection for high-fidelity contrast encoding.

How the spike output of the retina enables human visual perception is not fully understood. Here, we address this at the sensitivity limit of vision by correlating human visual perception with the spike outputs of primate ON and OFF parasol (magnocellular) retinal ganglion cells in tightly matching stimulus conditions. We show that human vision at its ultimate sensitivity limit depends on the spike output of the ON but not the OFF retinal pathway. Consequently, nonlinear signal processing in the retinal ON pathway precludes perceptual detection of single photons in darkness but enables quantal-resolution discrimination of differences in light intensity.

Conspicuity of staircase configuration: Effects of markings and contrast.

PURPOSE: To be able to walk safely up or down a staircase, we must be able to judge the configuration and slope of the staircase and our viewing position. Adding markings to the stairs might help form correct perceptions of the staircase geometry. In this study, we examined how visual judgements about staircase configuration are affected by different marking patterns. METHODS: Fifteen normally sighted young participants viewed computer-generated images of staircases as seen from the top landing of the stairs. Marking patterns included contrasting baseboard, transverse edge-stripes, longitudinal side-stripes, longitudinal stripes, diamond patterns, longitudinal stripes extended to landing and diamond patterns extended to landing. For comparison, we included the no-marking condition as a control. We tested several contrast levels of marking patterns (3.2%-50%), pitch lines of the staircases (shallow/medium/steep) and viewing positions (left/centre/right). The effect of the overall shape cue of the staircase on participants' performance was also evaluated. We measured participants' accuracies in judging whether the staircase was shallow, medium or steep, and whether the viewing position was located to the left, centre or right. RESULTS: Transverse edge-stripes markings yielded fewer underestimations of slope (9% [transverse] vs. 18% [others]) when compared with other markers. The presence of an overall shape cue helped both slope (67% [presence] vs. 51% [absence]) and viewing position judgements (79% [presence] vs. 62% [absence]). When the overall shape cue was present, only the transverse edge-stripes markings yielded a significant improvement in performance (compared with no-marking condition). When the cue was absent, performance was significantly better with markings with high and moderate contrasts. CONCLUSIONS: Adding marking patterns such as high-contrast transverse stripes to stairs may help enhance the visibility of the stairs and judgements of staircase geometry. This might be particularly useful for people with visual impairment or normally sighted individuals under compromised environmental conditions.

Assessment of large-diameter and small-diameter SoftK specialty contact lenses for early-stage keratoconus.

INTRODUCTION: Soft contact lenses may be a good alternative for early-stage keratoconus (KC) patients who do not tolerate rigid gas permeable (RGP) lenses due to ocular discomfort or complications. This prospective study compared outcomes obtained after 2 weeks of wearing two types of soft silicone hydrogel contact lenses for keratoconus that varied in their diameter and central thickness (cc). METHODS: Patients with Amsler-Krumeich grades I or II KC were fitted with small-diameter (14.2 or 14.8 mm) SoftK (SD-SoftK, cc = 0.48 mm) and large-diameter (17 mm) SoftK (LD-SoftK, cc = 0.60 mm) lenses, each worn for 2 weeks in a crossover design. Low (10%;10VA) and high (100%;100VA) contrast visual acuity, contrast sensitivity (CS, Pelli-Robson), higher order aberrations (HOAs, Visionix Vx130), the number of trial lens modifications during fitting and the subjectively preferred lens were compared using Friedman tests with post-hoc analysis. RESULTS: Forty eyes (N = 20, 10 males, mean age: 39.0 ± 9.9 years, range: 23-55 years) were examined. Their habitual median (interquartile1, interquartile3) 10VA (LogMAR), 100VA (LogMAR) and CS (LogCS) were 0.52 (0.30, 0.50), 0.14 (0.10, 0.15) and 1.35 (1.35, 1.50), respectively. For the SD-SoftK condition, the values were 0.23 (0.17, 0.30), 0.02 (0.00, 0.05) and 1.50 (1.50, 1.65), respectively. For the LD-SoftK condition, the respective values were 0.36 (0.27, 0.44), 0.09 (0.05, 0.13) and 1.50 (1.50, 1.60). SD-SoftK lenses significantly improved 10VA compared with habitual and LD-SoftK. SD-SoftK also significantly improved CS compared with habitual, but not LD-SoftK. LD-SoftK significantly improved spherical aberration compared with uncorrected (0.03 ± 0.10 µ vs. 0.07 ± 0.13 µ) but not SD-SoftK (0.04 ± 0.07 µ). Both lenses required a mean of 1.5 modifications prior to final lens fitting. Fewer adverse events were seen with SD-SoftK (N = 3) compared with LD-SoftK (N = 8), and 75% of participants preferred SD-SoftK lenses. CONCLUSION: SD-SoftK lenses were preferred by 75% of subjects, were associated with fewer adverse events and significantly improved 10VA compared with LD-SoftK lenses. SD-SoftK lenses also significantly improved CS compared with the habitual correction, but this did not differ significantly from the LD-SoftK lenses.

Safety of repeated low-level red-light therapy for children with myopia.

BACKGROUD: To investigate the safety of repetitive low-level red-light therapy (RLRLT) in children with myopia. METHODS: Children with myopia were assigned to the RLRL and control groups. Axial length (AL) and spherical equivalent refraction (SER) were followed up at 3-, 6-, and 12-month. To evaluate the safety of RLRLT, at 6 and 12 months in the RLRL group, multifocal electroretinography (mfERG) and contrast sensitivity were recorded. Furthermore, optical coherence tomography was used to measure the relative reflectance of the ellipsoid zone (rEZR), photoreceptor outer segment (rPOSR), and retinal pigment epithelium (rRPER). RESULTS: A total of 108 children completed the trial (55 in the RLRL group and 53 in the control group). After 3, 6, and 12 months, AL was shorter and SER less myopic in the RLRL group than in the control group. Regarding the safety of the RLRLT, the response density and amplitude of the P1 wave of the first ring of the mfERG increased significantly at 6 months (P = 0.001 and P = 0.017, respectively). At 6 and 12 months, contrast sensitivity at the high spatial frequency increased. Moreover, the rEZR increased significantly at 6 months (P = 0.029), the rPOSR increased significantly at 6 and 12 months (both P < 0.001), and the increase in rPOSR was greater with greater AL regression. CONCLUSIONS: Based on retinal function and structure follow-up, RLRLT was safe within 12 months. However, rEZR and rPOSR increased, the effects of this phenomenon requires further observation.

An ethologically relevant paradigm to assess defensive response to looming visual contrast stimuli.

In the animal kingdom, threat information is perceived mainly through vision. The subcortical visual pathway plays a critical role in the rapid processing of visual information-induced fear, and triggers a response. Looming-evoked behavior in rodents, mimicking response to aerial predators, allowed identify the neural circuitry underlying instinctive defensive behaviors; however, the influence of disk/background contrast on the looming-induced behavioral response has not been examined, either in rats or mice. We studied the influence of the dark disk/gray background contrast in the type of rat and mouse defensive behavior in the looming arena, and we showed that rat and mouse response as a function of disk/background contrast adjusted to a sigmoid-like relationship. Both sex and age biased the contrast-dependent response, which was dampened in rats submitted to retinal unilateral or bilateral ischemia. Moreover, using genetically manipulated mice, we showed that the three type of photoresponsive retinal cells (i.e., cones, rods, and intrinsically photoresponsive retinal ganglion cells (ipRGCs)), participate in the contrast-dependent response, following this hierarchy: cones > > rods > > > ipRGCs. The cone and rod involvement was confirmed using a mouse model of unilateral non-exudative age-related macular degeneration, which only damages canonical photoreceptors and significantly decreased the contrast sensitivity in the looming arena.

Transparent layer constancy improves with increased naturalness of the scene.

The extent to which hue, saturation, and transmittance of thin light-transmitting layers are perceived as constant when the illumination changes (transparent layer constancy, TLC) has previously been investigated with simple stimuli in asymmetric matching tasks. In this task, a target filter is presented under one illumination and a second filter is matched under a second illumination. Although two different illuminations are applied in the stimulus generation, there is no guarantee that the stimulus will be interpreted appropriately by the visual system. In previous work, we found a higher degree of TLC when both illuminations were presented alternately than when they were presented simultaneously, which could be explained, for example, by an increased plausibility of an illumination change. In this work, we test whether TLC can also be increased in simultaneous presentation when the filter's belonging to a particular illumination context is made more likely by additional cues. To this end, we presented filters in differently lit areas of complex, naturalistically rendered 3D scenes containing different types of cues to the prevailing illumination, such as scene geometry, object shading, and cast shadows. We found higher degrees of TLC in such complex scenes than in colorimetrically similar simple 2D color mosaics, which is consistent with the results of similar studies in the area of color constancy. To test which of the illumination cues available in the scenes are actually used, the different types of cues were successively removed from the naturalistically rendered complex scene. A total of eight levels of scene complexity were examined. As expected, TLC decreased the more cues were removed. Object shading and illumination gradients due to shadow cast were both found to have a positive effect on TLC. A second filter had a small positive effect on TLC when added in strongly reduced scenes, but not in the complex scenes that already provide many cues about the illumination context of the filter.

The color of fruits in photographs and still life paintings.

Still life paintings comprise a wealth of data on visual perception. Prior work has shown that the color statistics of objects show a marked bias for warm colors. Here, we ask about the relative chromatic contrast of these object-associated colors compared with background colors in still life paintings. We reasoned that, owing to the memory color effect, where the color of familiar objects is perceived more saturated, warm colors will be relatively more saturated than cool colors in still life paintings as compared with photographs. We analyzed color in 108 slides of still life paintings of fruit from the teaching slide collection of the Fogg University Art Museum and 41 color-calibrated photographs of fruit from the McGill data set. The results show that the relatively higher chromatic contrast of warm colors was greater for paintings compared with photographs, consistent with the hypothesis.