Showing papers on "Foveal published in 2021"

Optical coherence tomography angiography findings in patients with COVID-19.

Abstract: OBJECTIVE: To examine the changes in choriocapillaris and retina caused by coronavirus disease 2019 (COVID-19) by comparing optical coherence tomography angiography (OCTA) findings of COVID-19 patients and healthy controls. METHODS: The study and control groups consisted of 54 eyes of 27 participants, each. Patients and controls underwent OCTA examination. Foveal zone vessel density and parafoveal zone vessel density (for 4 quadrants: nasal, temporal, superior, inferior) were calculated for both superficial and deep capillary plexuses. Additionally, choriocapillaris flow and foveal avascular zone areas were calculated. RESULTS: For the parafoveal area in the study group, vessel density was significantly lower in the superior and nasal quadrants of the superficial capillary plexus and in all quadrants of the deep capillary plexus compared with controls (p < 0.05 for all). The study group had significantly higher choriocapillaris flow area values compared with controls (p = 0.042). CONCLUSION: Reduced vessel density of the retinal capillary plexus was detected in COVID-19 patients who may be at risk for retinal vascular complications.

Genetic variation affects morphological retinal phenotypes extracted from UK Biobank optical coherence tomography images

Abstract: Optical Coherence Tomography (OCT) enables non-invasive imaging of the retina and is used to diagnose and manage ophthalmic diseases including glaucoma. We present the first large-scale genome-wide association study of inner retinal morphology using phenotypes derived from OCT images of 31,434 UK Biobank participants. We identify 46 loci associated with thickness of the retinal nerve fibre layer or ganglion cell inner plexiform layer. Only one of these loci has been associated with glaucoma, and despite its clear role as a biomarker for the disease, Mendelian randomisation does not support inner retinal thickness being on the same genetic causal pathway as glaucoma. We extracted overall retinal thickness at the fovea, representative of foveal hypoplasia, with which three of the 46 SNPs were associated. We additionally associate these three loci with visual acuity. In contrast to the Mendelian causes of severe foveal hypoplasia, our results suggest a spectrum of foveal hypoplasia, in part genetically determined, with consequences on visual function.

Gaze-Contingent Retinal Speckle Suppression for Perceptually-Matched Foveated Holographic Displays

Abstract: Computer-generated holographic (CGH) displays show great potential and are emerging as the next-generation displays for augmented and virtual reality, and automotive heads-up displays. One of the critical problems harming the wide adoption of such displays is the presence of speckle noise inherent to holography, that compromises its quality by introducing perceptible artifacts. Although speckle noise suppression has been an active research area, the previous works have not considered the perceptual characteristics of the Human Visual System (HVS), which receives the final displayed imagery. However, it is well studied that the sensitivity of the HVS is not uniform across the visual field, which has led to gaze-contingent rendering schemes for maximizing the perceptual quality in various computer-generated imagery. Inspired by this, we present the first method that reduces the “perceived speckle noise” by integrating foveal and peripheral vision characteristics of the HVS, along with the retinal point spread function, into the phase hologram computation. Specifically, we introduce the anatomical and statistical retinal receptor distribution into our computational hologram optimization, which places a higher priority on reducing the perceived foveal speckle noise while being adaptable to any individual's optical aberration on the retina. Our method demonstrates superior perceptual quality on our emulated holographic display. Our evaluations with objective measurements and subjective studies demonstrate a significant reduction of the human perceived noise.

Flexible contextual modulation of naturalistic texture perception in peripheral vision.

Abstract: Peripheral vision comprises most of our visual field, and is essential in guiding visual behavior. Its characteristic capabilities and limitations, which distinguish it from foveal vision, have been explained by the most influential theory of peripheral vision as the product of representing the visual input using summary statistics. Despite its success, this account may provide a limited understanding of peripheral vision, because it neglects processes of perceptual grouping and segmentation. To test this hypothesis, we studied how contextual modulation, namely the modulation of the perception of a stimulus by its surrounds, interacts with segmentation in human peripheral vision. We used naturalistic textures, which are directly related to summary-statistics representations. We show that segmentation cues affect contextual modulation, and that this is not captured by our implementation of the summary-statistics model. We then characterize the effects of different texture statistics on contextual modulation, providing guidance for extending the model, as well as for probing neural mechanisms of peripheral vision.

HPS11 and OCA8: Two new types of albinism associated with mutations in BLOC1S5 and DCT genes.

Abstract: Albinism is a rare genetic condition associated with profound visual alterations and a variable hypopigmentation phenotype. The impairment of the visual system includes diagnostic foveal hypoplasia along with misrouting of retinal axons at the optic chiasm, whose consequences are a reduced visual acuity and altered stereoscopic vision, respectively. It is assumed that between 1:10,000-20,000 newborns can be a person with albinism, with great variations depending on world areas.

Evaluation of early and late COVID-19-induced vascular changes with optical coherence tomography angiography.

Abstract: OBJECTIVE: To evaluate vascular changes in the early period after coronavirus disease 2019 (COVID-19) infection and at 6-month follow-up METHODS: This study included 50 eyes of 25 patients who had been hospitalized for polymerase chain reaction-positive COVID-19 infection and 50 eyes of 25 healthy individuals All subjects underwent optical coherence tomography angiography using a 6 × 6 macular protocol in the early period after hospital discharge and 6 months later Foveal vessel density (VD) and parafoveal VD values were measured from 4 quadrants (superior, inferior, nasal, and temporal) of the superficial capillary plexus (SCP) and the deep capillary plexus (DCP) The choriocapillaris (CC) flow area and the foveal avascular zone area also were measured The OCTA measurements of the patient group were compared both between time points and with the control group at each time point RESULTS: COVID-19 patients showed lower VD values than control subjects in all parafoveal quadrants of both the SCP (superior, p = 001; inferior, p = 0048; nasal, p = 0003; temporal, p = 0048) and the DCP (superior, p = 0001; inferior, p = 0011; nasal, p = 0012; temporal, p = 0018) at the initial checkup and in all parafoveal quadrants of the SCP (superior, p = 00001; inferior, p = 0007; nasal, p = 0001; temporal, p = 0017) and in 2 of the parafoveal quadrants of the DCP (superior, p = 0003; inferior, p = 0016) at 6-month follow-up CC flow area values were significantly lower at the 6-month follow-up than at the initial examination (p = 0044) CONCLUSION: It is important to perform appropriate follow-up for COVID-19 patients because retinal vascular flow changes may persist in the long term

Eye Movements in Macular Degeneration.

Abstract: In healthy vision, the fovea provides high acuity and serves as the locus for fixation achieved through saccadic eye movements. Bilateral loss of the foveal regions in both eyes causes individuals ...

An image-computable model of how endogenous and exogenous attention differentially alter visual perception.

Abstract: Attention alters perception across the visual field. Typically, endogenous (voluntary) and exogenous (involuntary) attention similarly improve performance in many visual tasks, but they have differential effects in some tasks. Extant models of visual attention assume that the effects of these two types of attention are identical and consequently do not explain differences between them. Here, we develop a model of spatial resolution and attention that distinguishes between endogenous and exogenous attention. We focus on texture-based segmentation as a model system because it has revealed a clear dissociation between both attention types. For a texture for which performance peaks at parafoveal locations, endogenous attention improves performance across eccentricity, whereas exogenous attention improves performance where the resolution is low (peripheral locations) but impairs it where the resolution is high (foveal locations) for the scale of the texture. Our model emulates sensory encoding to segment figures from their background and predict behavioral performance. To explain attentional effects, endogenous and exogenous attention require separate operating regimes across visual detail (spatial frequency). Our model reproduces behavioral performance across several experiments and simultaneously resolves three unexplained phenomena: 1) the parafoveal advantage in segmentation, 2) the uniform improvements across eccentricity by endogenous attention, and 3) the peripheral improvements and foveal impairments by exogenous attention. Overall, we unveil a computational dissociation between each attention type and provide a generalizable framework for predicting their effects on perception across the visual field.

Dry Arthroscopy Distal Radioulnar Joint and Foveal Insertion: Surgical Technique

Abstract: Background Arthroscopy of the distal radioulnar joint is considered to be difficult to perform. At this time the integrity of the foveal insertion is indirectly evaluated with a hook test. If a hook test is positive it is inferred that the foveal insertion is torn or incompetent. Description of Technique The ideal way to evaluate the foveal insertion is by direct visualization and probing. In order to do this, arthroscopic examination of the distal radioulnar joint and foveal insertion is required. The article describes how to reliably perform “dry” arthroscopy of the distal radioulnar joint and foveal insertion using a 1.9 mm arthroscope to accurately assess the triangular fibrocartilage complex and foveal insertion. Patient and Methods A total of 169 dry DRUJ arthroscopies were performed by the primary author between January 2018 and February 2021. Results Using this technique, the foveal insertion was successfully visualized in 168 cases (99%). Conclusion Dry arthroscopy of the DRUJ is a reliable technique to evaluate the integrity of the foveal insertion.

Fast and nonuniform dynamics of perisaccadic vision in the central fovea.

Abstract: Humans use rapid eye movements (saccades) to inspect stimuli with the foveola, the region of the retina where receptors are most densely packed. It is well established that visual sensitivity is generally attenuated during these movements, a phenomenon known as saccadic suppression. This effect is commonly studied with large, often peripheral, stimuli presented during instructed saccades. However, little is known about how saccades modulate the foveola and how the resulting dynamics unfold during natural visual exploration. Here we measured the foveal dynamics of saccadic suppression in a naturalistic high-acuity task, a task designed after primates’ social grooming, which—like most explorations of fine patterns—primarily elicits minute saccades (microsaccades). Leveraging on recent advances in gaze-contingent display control, we were able to systematically map the perisaccadic time course of sensitivity across the foveola. We show that contrast sensitivity is not uniform across this region and that both the extent and dynamics of saccadic suppression vary within the foveola. Suppression is stronger and faster in the most central portion, where sensitivity is generally higher and selectively rebounds at the onset of a new fixation. These results shed light on the modulations experienced by foveal vision during the saccade-fixation cycle and explain some of the benefits of microsaccades.

Vision as oculomotor reward: cognitive contributions to the dynamic control of saccadic eye movements

Abstract: Humans and other primates are equipped with a foveated visual system. As a consequence, we reorient our fovea to objects and targets in the visual field that are conspicuous or that we consider relevant or worth looking at. These reorientations are achieved by means of saccadic eye movements. Where we saccade to depends on various low-level factors such as a targets' luminance but also crucially on high-level factors like the expected reward or a targets' relevance for perception and subsequent behavior. Here, we review recent findings how the control of saccadic eye movements is influenced by higher-level cognitive processes. We first describe the pathways by which cognitive contributions can influence the neural oculomotor circuit. Second, we summarize what saccade parameters reveal about cognitive mechanisms, particularly saccade latencies, saccade kinematics and changes in saccade gain. Finally, we review findings on what renders a saccade target valuable, as reflected in oculomotor behavior. We emphasize that foveal vision of the target after the saccade can constitute an internal reward for the visual system and that this is reflected in oculomotor dynamics that serve to quickly and accurately provide detailed foveal vision of relevant targets in the visual field.

Foveal Differentiation and Inner Retinal Displacement Are Arrested in Extremely Premature Infants.

Abstract: Purpose Children with a history of prematurity often have poorly developed foveae but when during development foveal differences arise. We hypothesize that the course of foveal development is altered from the time of preterm birth. Methods Eyes of 102 preterm infants undergoing retinopathy of prematurity screening examinations in the STudy of Eye imaging in Premature infantS (BabySTEPS) (NCT02887157) were serially imaged between 30 and 42 weeks postmenstrual age (PMA) using handheld optical coherence tomography systems. Total retinal thickness, inner retinal layer (IRL) thickness, and outer retinal layer (ORL) thickness were measured at the foveal center and parafovea. Foveal put depth, IRL thickness, and ORL thickness were compared between infants born at different gestational ages using mixed effects models. Results Foveal pit depth and IRL thickness were inversely related to gestational age; on average, the most premature infants had the thickest IRL and shallowest pits at all PMAs. Differences were evident by 30 weeks PMA and persisted through 42 weeks PMA. The foveal pits of the most premature infants did not progressively deepen, and the IRLs did not continue to thin with increasing chronological age. Conclusions Foveation in extremely preterm infants is arrested from the earliest observed ages and fails to progress through term equivalent age. The developmental displacement of the IRL from the foveal center into the parafovea does not occur normally after preterm birth. These observations suggest that foveal hypoplasia seen in children with history of prematurity is due to disturbances in foveal development that manifest within weeks of birth.

The effect of target salience and size in visual search within naturalistic scenes under degraded vision

Abstract: We address two questions concerning eye guidance during visual search in naturalistic scenes. First, search has been described as a task in which visual salience is unimportant. Here, we revisit this question by using a letter-in-scene search task that minimizes any confounding effects that may arise from scene guidance. Second, we investigate how important the different regions of the visual field are for different subprocesses of search (target localization, verification). In Experiment 1, we manipulated both the salience (low vs. high) and the size (small vs. large) of the target letter (a “T”), and we implemented a foveal scotoma (radius: 1°) in half of the trials. In Experiment 2, observers searched for high- and low-salience targets either with full vision or with a central or peripheral scotoma (radius: 2.5°). In both experiments, we found main effects of salience with better performance for high-salience targets. In Experiment 1, search was faster for large than for small targets, and high-salience helped more for small targets. When searching with a foveal scotoma, performance was relatively unimpaired regardless of the target's salience and size. In Experiment 2, both visual-field manipulations led to search time costs, but the peripheral scotoma was much more detrimental than the central scotoma. Peripheral vision proved to be important for target localization, and central vision for target verification. Salience affected eye movement guidance to the target in both central and peripheral vision. Collectively, the results lend support for search models that incorporate salience for predicting eye-movement behavior.

Foveal changes in aquaporin-4 antibody seropositive neuromyelitis optica spectrum disorder are independent of optic neuritis and not overtly progressive.

Abstract: Background and purpose Foveal changes were reported in aquaporin-4 antibody (AQP4-Ab) seropositive neuromyelitis optica spectrum disorder (NMOSD) patients; however, it is unclear whether they are independent of optic neuritis (ON), stem from subclinical ON or crossover from ON in fellow eyes. Fovea morphometry and a statistical classification approach were used to investigate if foveal changes in NMOSD are independent of ON and progressive. Methods This was a retrospective longitudinal study of 27 AQP4-IgG + NMOSD patients (49 eyes; 15 ON eyes and 34 eyes without a history of ON [NON eyes]), follow-up median (first and third quartile) 2.32 (1.33-3.28), and 38 healthy controls (HCs) (76 eyes), follow-up median (first and third quartile) 1.95 (1.83-2.54). The peripapillary retinal nerve fibre layer thickness and the volume of combined ganglion cell and inner plexiform layer as measures of neuroaxonal damage from ON were determined by optical coherence tomography. Nineteen foveal morphometry parameters were extracted from macular optical coherence tomography volume scans. Data were analysed using orthogonal partial least squares discriminant analysis and linear mixed effects models. Results At baseline, foveal shape was significantly altered in ON eyes and NON eyes compared to HCs. Discriminatory analysis showed 81% accuracy distinguishing ON vs. HCs and 68% accuracy in NON vs. HCs. NON eyes were distinguished from HCs by foveal shape parameters indicating widening. Orthogonal partial least squares discriminant analysis discriminated ON vs. NON with 76% accuracy. In a follow-up of 2.4 (20.85) years, no significant time-dependent foveal changes were found. Conclusion The parafoveal area is altered in AQP4-Ab seropositive NMOSD patients suggesting independent neuroaxonal damage from subclinical ON. Longer follow-ups are needed to confirm the stability of the parafoveal structure over time.

Active vision at the foveal scale in the primate superior colliculus.

Abstract: The primate superior colliculus (SC) has recently been shown to possess both a large foveal representation as well as a varied visual processing repertoire This structure is also known to contribu

Misalignment between center of foveal avascular zone and center of foveal photoreceptors in eyes with idiopathic epiretinal membrane.

Abstract: PURPOSE To determine the degree of misalignment between the center of foveal avascular zone and the center of foveal photoreceptors in eyes with an idiopathic epiretinal membrane (ERM). METHODS We reviewed the medical records of 61 eyes with an idiopathic ERM. A 3 × 3 mm area centered on the fovea was scanned with optical coherence tomography angiography before and at 6 months after surgery. The center of foveal avascular zone and the center of foveal photoreceptors were detected by en-face optical coherence tomography angiography images and sequential optical coherence tomography B-sections in the macular region. The presence or absence of ectopic inner foveal layers was also evaluated. RESULTS The mean distance from the center of foveal photoreceptors to the center of foveal avascular zone was 111.7 ± 106.8 µm in eyes with preoperative ERM. This distance was significantly correlated with the preoperative central foveal thickness (r = 0.33, P = 0.0104). Preoperatively, the ectopic inner foveal layers were present in 27 (44.3%) of 61 eyes. The foveal misalignment was greater in eyes with ectopic inner foveal layers than in those without ectopic inner foveal layers (158.6 ± 140.0 vs. 74.4 ± 45.4 µm, P < 0.0003). At 6 months after ERM surgery, the foveal misalignment was significantly reduced to 73.7 ± 48.0 µm (P = 0.0018). CONCLUSION Determining the degree of misalignment between the center of foveal avascular zone and the center of foveal photoreceptors might be a useful way to evaluate the degree of ERM traction.

An image-computable model on how endogenous and exogenous attention differentially alter visual perception

Abstract: Attention alters perception across the visual field. Typically, endogenous (voluntary) and exogenous (involuntary) attention similarly improve performance in many visual tasks, but they have differential effects in some tasks. Extant models of visual attention assume that the effects of these two types of attention are identical and consequently do not explain differences between them. Here, we develop a model of spatial resolution and attention that distinguishes between endogenous and exogenous attention. We focus on texture-based segmentation as a model system because it has revealed a clear dissociation between both attention types. For a texture for which performance peaks at parafoveal locations, endogenous attention improves performance across eccentricity, whereas exogenous attention improves performance where the resolution is low (peripheral locations) but impairs it where the resolution is high (foveal locations) for the scale of the texture. Our model emulates sensory encoding to segment figures from their background and predict behavioral performance. To explain attentional effects, endogenous and exogenous attention require separate operating regimes across visual detail (spatial frequency). Our model reproduces behavioral performance across several experiments and simultaneously resolves three unexplained phenomena: (1) the parafoveal advantage in segmentation, (2) the uniform improvements across eccentricity by endogenous attention and (3) the peripheral improvements and foveal impairments by exogenous attention. Overall, we unveil a computational dissociation between each attention type and provide a generalizable framework for predicting their effects on perception across the visual field.

Beyond Fixation: detailed characterization of neural selectivity in free-viewing primates

Abstract: Virtually all vision studies use a fixation point to stabilize gaze, rendering stimuli on video screens fixed to retinal coordinates. This approach requires trained subjects, is limited by the accuracy of fixational eye movements, and ignores the role of eye movements in shaping visual input. To overcome these limitations, we developed a suite of hardware and software tools to study vision during natural behavior in untrained subjects. We show this approach recovers receptive fields and tuning properties of visual neurons from multiple cortical areas of marmoset monkeys. Combined with high-precision eye-tracking, it achieves sufficient resolution to recover the receptive fields of foveal V1 neurons. These findings demonstrate the power of this approach for characterizing neural response while simultaneously studying the dynamics of natural behavior.

FOVEA PLANA ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY: New Perspectives.

Abstract: PURPOSE To report on the reliability of optical coherence tomography angiography (OCTA) to diagnose fovea plana. METHODS A retrospective, cross-sectional, case-control study included patients with foveal persistence of the inner retinal layers, confirmed by spectral domain OCT, and superficial capillary plexus (SCP) and deep capillary plexus foveal vascularization confirmed by OCTA. A healthy control group was selected. The best-corrected visual acuity was obtained. Spectral-domain OCT was used for measuring the outer nuclear layer thickness, and OCTA determined the foveal avascular zone, SCP, and deep capillary plexus vascular density. RESULTS Optical coherence tomography angiography reliability, based on all parameters, reached 97%, whereas based only on SCP vascular density 91%. The plana group (n = 57) differed significantly from the control group (n = 28) in terms of foveal avascular zone, SCP, and deep capillary plexus foveal vascular density (P 30% or foveal avascular zone <0.1 mm2 had fovea plana. The best-corrected visual acuity of the plana group had no correlation with OCTA quantitative parameters (Pearson |r|<0.18, Spearman |r|<0.44). CONCLUSION Optical coherence tomography angiography has a high accuracy in diagnosing fovea plana, as its characteristics differ significantly from the normal population. The lack of correlation between the best-corrected visual acuity and OCTA parameters implies that reduced the best-corrected visual acuity is likely to result from coexistent diseases rather than from the foveal structure.

What is visible across the visual field

Abstract: It is sometimes claimed that because the resolution and sensitivity of visual perception are better in the fovea than in the periphery, peripheral vision cannot support the same kinds of colour and sharpness percepts as foveal vision. The fact that a scene nevertheless seems colourful and sharp throughout the visual field then poses a puzzle. In this study, I use a detailed model of human spatial vision to estimate the visibility of certain properties of natural scenes, including aspects of colourfulness, sharpness, and blurriness, across the visual field. The model is constructed to reproduce basic aspects of human contrast and colour sensitivity over a range of retinal eccentricities. I apply the model to colourful, complex natural scene images, and estimate the degree to which colour and edge information are present in the model's representation of the scenes. I find that, aside from the intrinsic drift in the spatial scale of the representation, there are not large qualitative differences between foveal and peripheral representations of 'colourfulness' and 'sharpness'.

Foveal structure, function and microvascular morphology in school-age children with laser-treated retinopathy of prematurity.

Abstract: The purpose of this retrospective case-control study was to evaluate the relationship between foveal structure, function, microvascular morphology and visual acuity in school-age children with laser-treated retinopathy of prematurity (ROP). Foveal structural parameters, including the central foveal thickness (CFT), inner retinal thickness (IRT) and outer retinal thickness (ORT), were measured on B-scans using an Optovue XR Avanti optical coherence tomography device. Foveal microvascular parameters, including the foveal avascular zone (FAZ), superficial capillary plexus-vessel density (SCP-VD) and deep capillary plexus-vessel density (DCP-VD), were measured on optical coherence tomography angiography with a scan size of 3 × 3. The P1 amplitudes and P1 implicit times were recorded by a multifocal electroretinogram with 61 elements. Fifty-five eyes (26 eyes of school-age ROP children and 29 eyes of full-term controls) were analysed. The ROP children manifested a significantly smaller FAZ, higher SCP-VD and higher DCP-VD than the controls (p < 0.001). The CFT (p < 0.001), IRT (p < 0.001) and ORT (p = 0.001) were significantly increased in the ROP group. The P1 amplitudes in all five-ring retinal regions were significantly smaller in the ROP group (p < 0.001). Multivariable analysis indicated that best-corrected visual acuity was positively correlated with post-menstrual age (PMA) and negatively correlated with SCP-VD and CFT (R2 = 0.529, p < 0.001, 0.043 and 0.020, respectively). The foveal structure, function and microvascular morphology are affected in school-age children with laser-treated ROP. PMA, foveal structural anomalies and microvascular changes in ROP children were associated with impaired visual function.

Comparison of foveal optical coherence tomography angiography findings between premature children with ROP and non-premature healthy children.

Abstract: Our aim is to compare foveal microvascular structure, foveal retinal thickness, and best-corrected visual acuity (BCVA) in children with a history of premature retinopathy (ROP) and healthy children. It is also evaluated whether microvascular structural changes in the course of ROP had resulted from treatment modalities of ROP or the disease itself. This is a cross-sectional observational comparative study. Seventy-one children were analyzed in four different groups: children treated with bevacizumab (18), or laser (19) for ROP; or spontaneously regressed disease (18) and non-premature healthy children (16). We analyzed foveal avascular zone (FAZ) and vessel densities (VDs) of the superficial capillary plexus (SCP) and deep capillary plexus (DCP) at foveal and parafoveal region with optical coherence tomography angiography (OCT-A). Foveal thickness was measured by cross-sectional OCT. Correlations between FAZ area, foveal VD, central foveal thickness (CFT), BCVA, gestational age (GA), and birth weight (BW) were evaluated. After comparing of OCT-A parameters between all premature children (groups 1–3) and non-premature children (group 4), significant differences were found in VD-SCP (whole), VD-SCP (foveal), VD-SCP (parafoveal), CFT, and VD-DCP (foveal) (all p < 0.001). Significantly smaller FAZ area was also noted in ROP children. Higher foveal VD of SCP, DCP, and smaller FAZ area were significantly associated with lower GA and BW. By using OCT-A, significant foveal microvascular anomalies were identified in children with ROP irrespective of the treatment option or spontaneous regression. There has been a correlation between microvascular anomalies, CFT, and a lower BCVA.

MicroRNA Signatures of the Developing Primate Fovea.

Abstract: Rod and cone photoreceptors differ in their shape, photopigment expression, synaptic connection patterns, light sensitivity, and distribution across the retina. Although rods greatly outnumber cones, human vision is mostly dependent on cone photoreceptors since cones are essential for our sharp visual acuity and color discrimination. In humans and other primates, the fovea centralis (fovea), a specialized region of the central retina, contains the highest density of cones. Despite the vast importance of the fovea for human vision, the molecular mechanisms guiding the development of this region are largely unknown. MicroRNAs (miRNAs) are small post-transcriptional regulators known to orchestrate developmental transitions and cell fate specification in the retina. Here, we have characterized the transcriptional landscape of the developing rhesus monkey retina. Our data indicates that non-human primate fovea development is significantly accelerated compared to the equivalent retinal region at the other side of the optic nerve head, as described previously. Notably, we also identify several miRNAs differentially expressed in the presumptive fovea, including miR-15b-5p, miR-342-5p, miR-30b-5p, miR-103-3p, miR-93-5p as well as the miRNA cluster miR-183/-96/-182. Interestingly, miR-342-5p is enriched in the nasal primate retina and in the peripheral developing mouse retina, while miR-15b is enriched in the temporal primate retina and increases over time in the mouse retina in a central-to-periphery gradient. Together our data constitutes the first characterization of the developing rhesus monkey retinal miRNome and provides novel datasets to attain a more comprehensive understanding of foveal development.

Spectral domain optical coherence tomography findings in a case of whiplash maculopathy with incomplete resolution.

Abstract: PURPOSE To report spectral domain optical coherence tomography (OCT) findings of a patient who experienced bilateral visual loss after a motorcycle accident. METHODS A 51-year-old man presented to the emergency department complaining of bilateral visual loss after a motorcycle falling down. A complete ophthalmologic examination and OCT testing were made on the same day of the accident. Follow-up was made at 2 days, 2 weeks, 5 months, and 12 months adding central visual field assessment using Humphrey automated perimetry. RESULTS At presentation, best-corrected visual acuity was 20/200 in both eyes, anterior segment was normal, and fundus examination showed a bilateral macular edema confirmed by OCT. After 2 days, visual acuity recovered to 20/25. Optical coherence tomography findings showed foveal detachment, hyperreflective clump below external limiting membrane, and hyperreflectivity of Henle layer nasally to the fovea. After 15 days, visual acuity was 20/20, but vision was altered by a paracentral scotoma and some irregularities of OCT findings persisted. At 1 year of follow-up, best-corrected visual acuity was 20/20, and paracentral scotoma was very tiny in the right eye, whereas larger and deeper in the left eye. Optical coherence tomography was normal in the right eye, whereas some fragmentations of interdigitation zone were still evident in the left eye. CONCLUSION We report a case of bilateral whiplash maculopathy from vitreoretinal traction subsequent to road traffic accident. After 1 year of follow-up, visual acuity was restored but paracentral scotoma persisted. Optical coherence tomography appearance of the left eye was still abnormal.