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OBJECTIVE:To estimate the prevalence of ocular disease and obtain normative ocular data for free-living hummingbirds. ANIMALS STUDIED:Two hundred and sixty-three free-living, adult Hummingbirds from coastal and inland central California were studied, including Anna's (Calypte anna, n = 186) and Black-chinned (Archilochus alexandri; n = 77) hummingbirds. PROCEDURES:Slit lamp biomicroscopy and indirect ophthalmoscopy were performed on all individuals. Rebound tonometry, measurement of horizontal palpebral fissure length, and streak retinoscopy were performed on select individuals. Five conscious Anna's Hummingbirds underwent ocular imaging including fundus photography, digital slit lamp photography, and anterior segment and retinal optical coherence tomography. RESULTS:The prevalence of ocular disease in this population was 2.28%. Ocular imaging revealed a thin cornea, shallow anterior chamber, large lens, and a single central, deep convexiclivate fovea. Mean ± SD intraocular pressure was 11.21 ± 2.23 mm Hg. Mean ± SD eyelid length was 2.59 ± 0.19 mm. All eyes were emmetropic or mildly hyperopic with a mean (range) ± SD refractive error of +0.32 (-0.25 to +1) ± 0.33 diopters. CONCLUSIONS:Consistent with previous reports, these data suggest that hummingbirds have visual characteristics found in predatory and prey species, as well as a low prevalence of spontaneous ocular disease. This work provides a set of reference values and clinical findings that can be used in the future research on hummingbird vision and ocular disease. It also provides representative diagnostic images of normal birds and demonstrates that advanced ocular imaging can be performed on manually restrained hummingbirds without pharmacologic dilation.

The issues in the organization of the human retina are analyzed from the point of view of cybernetics. In particular, hypotheses are formed regarding the conditions of the concentric organization of receptive fields, the extraction of informative features, the possibilities of restructuring the receptive fields and their limitations, the transmission of information through ganglion cells with its binding to the location on the retina, as well as regarding the peculiarities of the visual system in different modes. The conditions for the correct operation of on- and off-centers of receptive fields based on bipolars with a cone as the central zone of excitation and the surrounding rods as an inhibition zone, organized with the help of horizontal cells for the on-center, and vice versa for the off-center, are determined. The conditions for the extraction of informative features based on on- and off-centers in the form of point values of brightness differences between neighboring elements are substantiated. The rigid organization of the receptive fields of ganglion cells and the limited possibilities of its reconstruction are substantiated. A hypothesis on the organization of the transmission of information about brightness differences from bipolar cells through ganglion cells under the control of amacrine cells with reference to the location of the retina is proposed. A hypothesis on the continuous perception of the image by the retina receptors and the discrete perception of information by the brain is formulated. The features of the visual system in the modes of contemplation, searching for an object in an image, tracking it, and detailed examination and recognition are considered. [ABSTRACT FROM AUTHOR]

Appropriate patterning of the retina during embryonic development is assumed to underlie the establishment of spatially localised specialisations that mediate the perception of specific visual features. For example, in zebrafish, an area involved in high acuity vision (HAA) is thought to be present in the ventro-temporal retina. Here, we show that the interplay of the transcription factor Rx3 with Fibroblast Growth Factor and Hedgehog signals initiates and restricts foxd1 expression to the prospective temporal retina, initiating naso-temporal regionalisation of the retina. Abrogation of Foxd1 results in the loss of temporal and expansion of nasal retinal character, and consequent absence of the HAA. These structural defects correlate with severe visual defects, as assessed in optokinetic and optomotor response assays. In contrast, optokinetic responses are unaffected in the opposite condition, in which nasal retinal character is lost at the expense of expanded temporal character. Our study indicates that the establishment of temporal retinal character during early retinal development is required for the specification of the HAA, and suggests a prominent role of the temporal retina in controlling specific visual functions. [ABSTRACT FROM AUTHOR]

Aging is the greatest risk factor for chronic human diseases, including many eye diseases. Geroscience aims to understand the effects of the aging process on these diseases, including the genetic, molecular, and cellular mechanisms that underlie the increased risk of disease over the lifetime. Understanding of the aging eye increases general knowledge of the cellular physiology impacted by aging processes at various biological extremes. Two major diseases, age-related cataract and age-related macular degeneration (AMD) are caused by dysfunction of the lens and retina, respectively. Lens transparency and light refraction are mediated by lens fiber cells lacking nuclei and other organelles, which provides a unique opportunity to study a single aging hallmark, i.e., loss of proteostasis, within an environment of limited metabolism. In AMD, local dysfunction of the photoreceptors/retinal pigmented epithelium/Bruch's membrane/choriocapillaris complex in the macula leads to the loss of photoreceptors and eventually loss of central vision, and is driven by nearly all the hallmarks of aging and shares features with Alzheimer's disease, Parkinson's disease, cardiovascular disease, and diabetes. The aging eye can function as a model for studying basic mechanisms of aging and, vice versa, well-defined hallmarks of aging can be used as tools to understand age-related eye disease. • Review of common mechanisms and contrasts between age related cataracts and macular degeneration • Analysis of multitasking functions of the retinal pigment epithelium and general biology of aging • Up-to-date summary of aging compensatory mechanisms in lens and retinal pigmented epithelium • Novel insights into the origin of lens crystallins in the drusen deposits • Summary of recent finding regarding structure and function of individual crystallin proteins [ABSTRACT FROM AUTHOR]

To describe a surgical approach for open repair of the triangular fibrocartilage complex foveal avulsion via ulnar styloid osteotomy, and to assess its clinical results. We reviewed 12 patients with distal radioulnar joint (DRUJ) instability due to isolated foveal avulsion of DRUJ ligaments. Wrist arthroscopy was conducted for all patients to exclude the presence of concomitant tear of the superficial part of the triangular fibrocartilage complex and to corroborate the diagnosis with a positive hook test. Through an ulnar approach between flexor and extensor carpi ulnaris, an ulnar styloid osteotomy was performed under image intensifier control just ulnar to the fovea of the head of the ulna. The avulsed foveal attachment was anchored through transosseous sutures passing from the fovea to the neck of the ulna. The ulnar styloid was fixed by means of screws or tension band wires. Outcome measures included clinical assessment of pain (visual analog scale), grip strength, DRUJ instability, range of motion of the wrist, and modified Mayo wrist score. Radiographic assessment was done to determine union of the ulnar styloid osteotomy, DRUJ subluxation, and any hardware-related problems. Outcome measures were evaluated after a mean follow-up of 21 months. Healing of the osteotomy was obtained in all cases by 11 weeks. The DRUJ laxity, visual analog scale, and modified Mayo wrist score improved, while grip strength and range of motion remained unchanged. One patient had prominent hardware necessitating removal after union of the osteotomy. There were no reported cases of injury or neuropraxia of the dorsal cutaneous branch of the ulnar nerve. Open repair of an avulsed foveal attachment of the triangular fibrocartilage complex using an ulnar styloid osteotomy is an alternative to either open or arthroscopic repair approaches. Therapeutic IV. [ABSTRACT FROM AUTHOR]

A 44-year-old female with a vision of 10/200 in the right eye had double pits in the temporal segment of the optic disc with serous macular detachment. Spectral-domain optical coherence tomography (SD-OCT) confirmed serous retinal detachment, an outer layer hole, and double optic disc pits. The patient underwent pars plana vitrectomy with modified ILM flap surgery involving fovea-sparing internal limiting membrane peeling (FSIP) technique with inverted ILM flap tucking with gas tamponade. Post surgery, the communications between perineural and intraretinal spaces were obliterated with flaps of ILM covering the pits, with reduced serous macular detachment and BCVA of 20/120. FSIP with inverted internal limiting membrane flap tuck can be an effective technique to manage rare cases of double ODP-M.

Psychophysical inferences about the neural mechanisms supporting spatial vision can be undermined by uncertainties introduced by optical aberrations and fixational eye movements, particularly in fovea where the neuronal grain of the visual system is fine. We examined the effect of these preneural factors on photopic spatial summation in the human fovea using a custom adaptive optics scanning light ophthalmoscope that provided control over optical aberrations and retinal stimulus motion. Consistent with previous results, Ricco's area of complete summation encompassed multiple photoreceptors when measured with ordinary amounts of ocular aberrations and retinal stimulus motion. When both factors were minimized experimentally, summation areas were essentially unchanged, suggesting that foveal spatial summation is limited by postreceptoral neural pooling. We compared our behavioral data to predictions generated with a physiologically-inspired front-end model of the visual system, and were able to capture the shape of the summation curves obtained with and without pre-retinal factors using a single postreceptoral summing filter of fixed spatial extent. Given our data and modeling, neurons in the magnocellular visual pathway, such as parasol ganglion cells, provide a candidate neural correlate of Ricco's area in the central fovea.

The macula and fovea comprise a highly sensitive visual detection tissue that is susceptible to common disease processes like age-related macular degeneration (AMD). Our understanding of the molecular determinants of high acuity vision remains unclear, as few model organisms possess a human-like fovea. We explore transcription factor networks and receptor-ligand interactions to elucidate tissue interactions in the macula and peripheral retina and concomitant changes in the underlying retinal pigment epithelium (RPE)/choroid. Poly-A selected, 100 bp paired-end RNA-sequencing (RNA-seq) was performed across the macular/foveal, perimacular, and temporal peripheral regions of the neural retina and RPE/choroid tissues of four adult Rhesus macaque eyes to characterize region- and tissue-specific gene expression. RNA-seq reads were mapped to both the macaque and human genomes for maximum alignment and analyzed for differential expression and Gene Ontology (GO) enrichment. Comparison of the neural retina and RPE/choroid tissues indicated distinct, contiguously changing gene expression profiles from fovea through perimacula to periphery. Top GO enrichment of differentially expressed genes in the RPE/choroid included cell junction organization and epithelial cell development. Expression of transcriptional regulators and various disease-associated genes show distinct location-specific preference and retina-RPE/choroid tissue-tissue interactions. Regional gene expression changes in the macaque retina and RPE/choroid is greater than that found in previously published transcriptome analysis of the human retina and RPE/choroid. Further, conservation of human macula-specific transcription factor profiles and gene expression in macaque tissues suggest a conservation of programs required for retina and RPE/choroid function and disease susceptibility.

To investigate the choroidal vascularity alterations of macula and peripapillary area in eyes with unilateral Fuchs uveitis (FU). This study included 18 eyes with unilateral FU and 18 healthy fellow eyes. The choroidal vascularity index (CVI) was analyzed, and the results were compared between eyes with FU and healthy fellow eyes (control group). The mean subfoveal (s)CVI (%) value was significantly lower in the FU group as compared with the control group: 60.92 ± 2.63 vs. 64.01 ± 2.54, respectively (p =.001). The mean pCVI (%) values of superior and inferior quadrant were significantly lower in the Fuchs group as compared with the control group:58.87 ± 4.48 vs. 61.98 ± 3.32, respectively, in superior quadrant (p =.035); and 57.29 ± 6.65 vs. 61.44 ± 4.76, respectively, in inferior quadrant (p =.014). The chronic continuous inflammation in FU causes inflammation-mediated thinning in the vascular area of the subfoveal and peripapillary choroid. The changes in the peripapillary region are remarkable in terms of the further glaucoma risk of these eyes. [ABSTRACT FROM AUTHOR]

During collective vigilance, it is commonly assumed that individual animals compromise their feeding time to be vigilant against predators, benefiting the entire group. One notable issue with this assumption concerns the unclear nature of predator 'detection', particularly in terms of vision. It remains uncertain how a vigilant individual utilizes its high-acuity vision (such as the fovea) to detect a predator cue and subsequently guide individual and collective escape responses. Using fine-scale motion-capture technologies, we tracked the head and body orientations of pigeons (hence reconstructed their visual fields and foveal projections) foraging in a flock during simulated predator attacks. Pigeons used their fovea to inspect predator cues. Earlier foveation on a predator cue was linked to preceding behaviors related to vigilance and feeding, such as head-up or down positions, head-scanning, and food-pecking. Moreover, earlier foveation predicted earlier evasion flights at both the individual and collective levels. However, we also found that relatively long delay between their foveation and escape responses in individuals obscured the relationship between these two responses. While our results largely support the existing assumptions about vigilance, they also underscore the importance of considering vision and addressing the disparity between detection and escape responses in future research., Competing Interests: MD, FK No competing interests declared, (© 2024, Delacoux and Kano.)

Optic Atrophy (OA) can be associated with the development of microcystic macular edema (MME) in the perifoveal retinal inner nuclear layer (INL). We aimed here to retrospectively determine the prevalence of MME in patients with non-glaucomatous OA in our tertiary ophthalmology department between 2015 and 2020. We then examined how MME affected the thicknesses of the different retinal layers and the differences in demographic and clinical characteristics between those patients who developed MME and those who did not. A total of 643 eyes (429 patients) were included (mean age 45.9 ± 17.8 years, 52% female). MME developed in 95 (15%) eyes and across all etiologies of OA except for toxic/nutritional causes, but the prevalence of MME varied between the different etiologies. The development of MME was associated with thinning of the ganglion cell layer (11.0 vs. 9.6 μm; p = 0.001) and the retinal nerve fiber layer (10.1 vs. 9.15 μm; p = 0.024), with INL thickening in the 3- and 6-mm diameter areas of the central fovea. Patients developing MME had significantly worse distance best-corrected visual acuity than those not developing MME (0.62 vs. 0.38 logMAR; p = 0.002). Overall, the presence of MME in OA cannot be used to guide the diagnostic work-up of OA.

This study's goal is to determine the accuracy of a linear classifier that predicts the prognosis of patients with macular edema (ME) due to a branch retinal vein occlusion during the maintenance phase of antivascular endothelial growth factor (anti-VEGF) therapy. The classifier was created using the clinical information and optical coherence tomographic (OCT) findings obtained up to the time of the first resolution of ME. In total, 66 eyes of 66 patients received an initial intravitreal injection of anti-VEGF followed by repeated injections with the pro re nata (PRN) regimen for 12 months. The patients were divided into two groups: those with and those without good vision during the PRN phase. The mean AUC of the classifier was 0.93, and the coefficients of the explanatory variables were: best-corrected visual acuity (BCVA) at baseline was 0.66, BCVA at first resolution of ME was 0.51, age was 0.21, the average brightness of the ellipsoid zone (EZ) was −0.12, the intactness of the external limiting membrane (ELM) was −0.14, the average brightness of the ELM was −0.17, the brightness value of EZ was −0.17, the area of the outer segments of the photoreceptors was −0.20, and the intactness of the EZ was −0.24. This algorithm predicted the prognosis over time for individual patients during the PRN phase. [ABSTRACT FROM AUTHOR]

Non-human animals tend to solve behavioral tasks using local information. Pigeons are particularly biased toward using the local features of stimuli to guide behavior in small-scale environments. When behavioral tasks are performed in large-scale environments, pigeons are much better global processors of information. The local and global strategies are mediated by two different fovea in the pigeon retina that are associated with the tectofugal and thalamofugal pathways. We discuss the neural mechanisms of pigeons' bias for local information within the tectofugal pathway, which terminates at an intermediate stage of extracting shape complexity. We also review the evidence suggesting that the thalamofugal pathway participates in global processing in pigeons and is primarily engaged in constructing a spatial representation of the environment in conjunction with the hippocampus. [ABSTRACT FROM AUTHOR]

Detection of abnormalities in human eye is one of the well-established research areas of Machine Learning. Deep Learning techniques are widely used for the diagnosis of Retinal Diseases (RD). Fovea is one of the significant parts of retina which would be prevented before the involvement of Perforated Blood Vessels (PBV). Retinopathy Images (RI) contains sufficient information to classify structural changes incurred upon PBV but Macular Features (MF) and Fovea Features (FF) are very difficult to detect because features of MF and FF could be found with Similar Color Movements (SCM) with minor variations. This paper presents novel method for the diagnosis of Irregular Fovea (IF) to assist the doctors in diagnosis of irregular fovea. By considering all above problems this paper proposes a three-layer decision support system to explore the hindsight knowledge of RI and to solve the classification problem of IF. The first layer involves data preparation, the second layer builds the decision model to extract the hidden patterns of fundus images by using Deep Belief Neural Network (DBN) and the third layer visualizes the results by using confusion matrix. This paper contributes a data preparation algorithm for irregular fovea and a highest estimated classification accuracy measured about 96.90%. [ABSTRACT FROM AUTHOR]

Purpose: Markers for the relationships between structural and microvasculature measures given by optical coherence tomography angiography are necessary to increase the diagnostic and prognostic value of this technique. The aim of this study was to investigate relationships between structural and microvasculature measures around the fovea in healthy eyes of healthy children. Methods: Observational cross‐sectional study involving children aged 8–17 years, born at full‐term, with no eye disease. The better of two 3 × 3 mm macular scans obtained with a Cirrus 5000HD‐OCT was analysed. Images were corrected for lateral magnification errors. Vessel density and perfusion were measured with ImageJ/Fiji software for the superficial capillary plexus. Structural measures including foveal and macular thicknesses were performed manually. Results: The sample included 86 participants, 51 (59%) females. Mean age was 12.4 years (SD = 2.5); mean best‐corrected acuity was −0.10 logMAR (SD = 0.09); mean refractive error was +0.59 D (SD = 1.3) and mean axial length was 23.1 mm (SD = 0.86). Mean area of the foveal avascular zone (AFAZ) was 0.20 mm2 (SD = 0.88); median fovea‐to‐macula thickness ratio (FMTR) was 0.63 (IQR = 0.08); mean central vessel density was 12.42 mm−1 (SD = 2.78) and mean central perfusion was 38.66% (SD = 3.83). AFAZ was correlated with central vessel density (p < 0.001), perfusion (p < 0.001), foveal thickness (p < 0.001) and FMTR (p < 0.001). Central vessel density was correlated with foveal thickness (p < 0.001) and FMTR, (p = 0.01). Central perfusion was correlated with foveal thickness (p < 0.001) and FMTR, (p = 0.003). Conclusion: In this study, foveal thickness, FMTR and foveal microvasculature measurements were correlated. Clinicians need to be aware that shallow foveal pits and persistent foveal microvasculature are likely to occur in optical coherence tomography angiography images. In healthy eyes from healthy children, an atypical high FMTR and a small AFAZ may be associated with incomplete foveal development. The mechanism and functional implications of this remain unknown. [ABSTRACT FROM AUTHOR]

Purpose: To identify the eyes with macular edema (ME) due to a branch retinal vein occlusion (BRVO) that have good visual acuity during the continuous anti-vascular endothelial growth factor (anti-VEGF) treatment based on the patients' clinical information and optical coherence tomography (OCT) images by using machine learning. Methods: Sixty-six eyes of 66 patients received 1 anti-VEGF injection followed by repeated injections in the pro re nata (PRN) regimen for 12 months. The patients were divided into two groups: those with and those without good vision during the 1-year experimental period. Handcraft features were defined from the OCT images at the time of the first resolution of the ME. Variables with a significant difference between the groups were used as explanatory variables. A classifier was created with handcrafted features based on a support vector machine (SVM) that adjusted parameters for increasing maximal precision. Results: The age, best-corrected visual acuity (BCVA) at the baseline, BCVA at the first resolution of the ME, integrity and reflectivity of the external limiting membrane (ELM), the ellipsoid zone (EZ), and area of the outer segments of the photoreceptors were selected as explanatory variables. The classification performance was 0.806 for accuracy, 0.768 for precision, 0.772 for recall, and 0.752 for the F-measure. Conclusion: The use of the SVM of the patient's clinical information and OCT images can be helpful for determining the prognosis of the BCVA during continued pro re nata anti-VEGF treatment in eyes with ME associated with BRVO. [ABSTRACT FROM AUTHOR]

AIM: To document with spectral-domain optical coherence tomography the morphological regeneration of the fovea after resolution of cystoid macular edema (CME) without and with internal limiting membrane (ILM) detachment and to discuss the presumed role of the glial scaffold for foveal structure stabilization. METHODS: A retrospective case series of 38 eyes of 35 patients is described. Of these, 17 eyes of 16 patients displayed foveal regeneration after resolution of CME, and 6 eyes of 6 patients displayed CME with ILM detachment. Eleven eyes of 9 patients displayed other kinds of foveal and retinal disorders associated with ILM detachment. RESULTS: The pattern of edematous cyst distribution, with or without a large cyst in the foveola and preferred location of cysts in the inner nuclear layer or Henle fiber layer (HFL), may vary between different eyes with CME or in one eye during different CME episodes. Large cysts in the foveola may be associated with a tractional elevation of the inner foveal layers and the formation of a foveoschisis in the HFL. Edematous cysts are usually not formed in the ganglion cell layer. Eyes with CME and ILM detachment display a schisis between the detached ILM and nerve fiber layer (NFL) which is traversed by Müller cell trunks. ILM detachment was also found in single eyes with myopic traction maculopathy, macular pucker, full-thickness macular holes, outer lamellar holes, and glaucomatous parapapillary retinoschisis, and in 3 eyes with Müller cell sheen dystrophy (MCSD). As observed in eyes with MCSD, cellophane maculopathy, and macular pucker, respectively, fundus light reflections can be caused by different highly reflective membranes or layers: the thickened and tightened ILM which may or may not be detached from the NFL, the NFL, or idiopathic epiretinal membranes. In eyes with short single or multiple CME episodes, the central fovea regenerated either completely, which included the disappearance of irregularities of the photoreceptor layer lines and the reformation of a fovea externa, or with remaining irregularities of the photoreceptor layer lines. CONCLUSION: The examples of a complete regeneration of the foveal morphology after transient CME show that the fovea may withstand even large tractional deformations and has a conspicuous capacity of structural regeneration as long as no cell degeneration occurs. It is suggested that the regenerative capacity depends on the integrity of the threedimensional glial scaffold for foveal structure stabilization composed of Müller cell and astrocyte processes. The glial scaffold may also maintain the retinal structure after loss of most retinal neurons as in late-stage MCSD.

Abstract Purpose To report a patient with impaired vision due to foveal involvement of toxoplasmic retinochoroiditis, who was successfully treated with intravitreal clindamycin and dexamethasone and oral therapy with azithromycin, trimethoprim-sulfamethoxazole, and prednisolone and led to successful visual and anatomic recovery. Case presentation A 32-year-old man presented with three-day history of gradually decreasing visual acuity, redness, pain and photophobia of the right eye. Anterior chamber cellular reaction, vitritis and a white retinochoroiditis patch with adjacent retinal vasculitis in the fovea was suggestive of the toxoplasmic retinochoroiditis. He was treated with intravitreal clindamycin and dexamethasone injection followed by six-week regimen of azithromycin, trimethoprim-sulfamethoxazole, and prednisolone. In serial optical coherence tomography imaging, retinitis patch changed to cavitary foveal destruction. Fovea reorganized gradually, and visual acuity concurrently improved from counting finger 3 m to 20/25. Conclusion In foveal toxoplasmic retinochoroiditis lesions, timely treatment is associated with retinal reorganization and visual improvement.

Non-human animals tend to solve behavioral tasks using local information. Pigeons are particularly biased toward using the local features of stimuli to guide behavior in small-scale environments. When behavioral tasks are performed in large-scale environments, pigeons are much better global processors of information. The local and global strategies are mediated by two different fovea in the pigeon retina that are associated with the tectofugal and thalamofugal pathways. We discuss the neural mechanisms of pigeons’ bias for local information within the tectofugal pathway, which terminates at an intermediate stage of extracting shape complexity. We also review the evidence suggesting that the thalamofugal pathway participates in global processing in pigeons and is primarily engaged in constructing a spatial representation of the environment in conjunction with the hippocampus.

Purpose: To understand consequences of reconstituting cone photoreceptor function in congenital binocular blindness resulting from mutations in the centrosomal protein 290 (CEP290) gene. Design: Phase 1b/2 open-label, multicenter, multiple-dose, dose-escalation trial. Participants: A homogeneous subgroup of 5 participants with light perception (LP) vision at the time of enrollment (age range, 15–41 years) selected for detailed analyses. Medical histories of 4 participants were consistent with congenital binocular blindness, whereas 1 participant showed evidence of spatial vision in early life that was later lost. Intervention: Participants received a single intravitreal injection of sepofarsen (160 or 320 μg) into the study eye. Main Outcome Measures: Full-field stimulus testing (FST), visual acuity (VA), and transient pupillary light reflex (TPLR) were measured at baseline and for 3 months after the injection. Results: All 5 participants with LP vision demonstrated severely abnormal FST and TPLR findings. At baseline, FST threshold estimates were 0.81 and 1.0 log cd/m2 for control and study eyes, respectively. At 3 months, study eyes showed a large mean improvement of –1.75 log versus baseline (P < 0.001), whereas untreated control eyes were comparable with baseline. Blue minus red FST values were not different than 0 (P = 0.59), compatible with cone mediation of remnant vision. At baseline, TPLR response amplitude and latency estimates were 0.39 mm and 0.72 seconds, respectively, for control eyes, and 0.28 mm and 0.78 seconds, respectively, for study eyes. At 3 months, study eyes showed a mean improvement of 0.44 mm in amplitude and a mean acceleration of 0.29 seconds in latency versus baseline (P < 0.001), whereas control eyes showed no significant change versus baseline. Specialized tests performed in 1 participant confirmed and extended the standardized results from all 5 participants. Conclusions: By subjective and objective evidence, intravitreal sepofarsen provides improvement of light sensitivity for individuals with LP vision. However, translation of increased light sensitivity to improved spatial vision may occur preferentially in those with a history of visual experience during early neurodevelopment. Interventions for congenital lack of spatial vision in CEP290-associated Leber congenital amaurosis may lead to better results if performed before visual cortex maturity.

The relationship of macular pigments and foveal anatomy to the perception of Maxwell’s spot (MS) and Haidinger’s brushes (HB) entoptic phenomena were investigated. Dual-wavelength-autofluorescence and OCT were used to define macular pigment density and foveal anatomy in 52 eyes. MS was generated by alternating unpolarized red/blue and red/green uniform field illumination. HB was generated by alternating the linear polarization axis of a uniform blue field. In Experiment 1, horizontal widths of MS and HB were measured using a micrometer system and compared with macular pigment densities and OCT-defined morphometry. MS radius (mean 1.4°) was significantly less than HB radius (mean 1.6°), with the spatial extent of both phenomena falling between the boundaries of the foveola and foveal pit. Multiple regression showed MS and HB radii to be significantly associated with the macular pigment spatial profile radius. HB radius, but not MS radius, was also significantly associated with foveolar morphometry. Experiment 2 compared perceptual profiles of MS with macular pigment distribution patterns and demonstrated close agreement. The size and appearance of MS is a direct indicator of macular pigment density and distribution. Measures of HB radii are less specific, with dependence on both macular pigment density and foveal structure.

A 44-year-old female with a vision of 10/200 in the right eye had double pits in the temporal segment of the optic disc with serous macular detachment. Spectral-domain optical coherence tomography (SD-OCT) confirmed serous retinal detachment, an outer layer hole, and double optic disc pits. The patient underwent pars plana vitrectomy with modified ILM flap surgery involving fovea-sparing internal limiting membrane peeling (FSIP) technique with inverted ILM flap tucking with gas tamponade. Post surgery, the communications between perineural and intraretinal spaces were obliterated with flaps of ILM covering the pits, with reduced serous macular detachment and BCVA of 20/120. FSIP with inverted internal limiting membrane flap tuck can be an effective technique to manage rare cases of double ODP-M. [ABSTRACT FROM AUTHOR]

A Working Group of the Society of Toxicologic Pathology's Scientific and Regulatory Policy Committee conducted a technical and scientific review of current practices relating to the fixation, trimming, and sectioning of the nonrodent eye to identify key points and species-specific anatomical landmarks to consider when preparing and evaluating eyes of rabbits, dogs, minipigs, and nonhuman primates from ocular and general toxicity studies. The topics addressed in this Points to Consider article include determination of situations when more comprehensive evaluation of the globe and/or associated extraocular tissues should be implemented (expanded ocular sampling), and what constitutes expanded ocular sampling. In addition, this manuscript highlights the practical aspects of fixing, trimming, and sectioning the eye to ensure adequate histopathological evaluation of all major ocular structures, including the cone-dense areas (visual streak/macula/fovea) of the retina for rabbits, dogs, minipigs, and nonhuman primates, which is a current regulatory expectation for ocular toxicity studies. This Points to Consider article is a product of a Society of Toxicologic Pathology (STP) Working Group commissioned by the Scientific and Regulatory Policy Committee (SRPC) of the STP. It has been reviewed and approved by the SRPC, Executive Committee of the STP, the European Society of Toxicologic Pathology, and the British Society of Toxicological Pathology, but it does not represent a formal Best Practice recommendation of the Society; rather, it is intended to provide key "points to consider" for the toxicologic pathology community. The points expressed in this document are those of the authors and do not reflect views or policies of the employing institutions. Readers of Toxicologic Pathology are encouraged to send their thoughts on this article or ideas for new topics to the editor. [ABSTRACT FROM AUTHOR]

Ethan Pillay, Thiroshnee Naidoo, Khadija Asmal, Lilitha Maliwa, Sinenhlanhla Mchunua, Diane Beverly van Staden, Nishanee Rampersad Discipline of Optometry, School of Health Sciences, University of KwaZulu-Natal, Durban X54001, South AfricaCorrespondence: Nishanee RampersadDiscipline of Optometry, School of Health Sciences, University of KwaZulu-Natal, Westville Campus, Private Bag, Durban X54001, South AfricaTel +27 31 260 7562Fax +27 31 260 7666Email rampersadn@ukzn.ac.zaIntroduction: The central retina is responsible for several visual functions and continues to develop postnatally. In albinism, which is a genetic disorder characterized by impaired melanin biosynthesis, the development of the central retina is prematurely arrested and results in foveal hypoplasia. Retinal thickness measurements can be determined non-invasively using optical coherence tomography systems. This article reports on the retinal thickness measurements of individuals with albinism in South Africa to aid in the assessment and management of affected individuals.Methods: The study used a comparative research design and included 60 individuals (30 albinism and 30 controls) aged from 10 to 30 years who accessed the eye clinic at a tertiary institution in KwaZulu-Natal, South Africa. The Optovue iVue100 optical coherence tomographer was used to measure retinal thickness in the nine Early Treatment Diabetic Retinopathy Study (ETDRS) sectors including the central foveal, parafoveal and perifoveal regions. Study data were analysed using descriptive and inferential statistics.Results: The mean central foveal thickness was significantly higher in individuals with albinism compared with controls (289 μm versus 239 μm, p < 0.001). In contrast, control participants showed thicker retinal thickness measurements in the other ETDRS sectors (p < 0.001). The nasal and temporal quadrants were thickest and thinnest, respectively, in the parafoveal and perifoveal regions for the albinism and control groups.Conclusion: Individuals with albinism, aged from 10 to 30 years, have higher central foveal thickness but thinner retinal thickness measurements in the parafoveal and perifoveal regions. Optometric personnel should consider these measurements when assessing individuals with albinism with foveal retinal diseases.Keywords: albinism, fovea, foveal hypoplasia, optical coherence tomography, retinal thickness

The localization of the optic disc and fovea is crucial in the automated diagnosis of various retinal diseases. We propose a novel deep learning driven heatmap regression model based on the encoder-decoder architecture for the joint detection of optic disc and fovea centers in color fundus images. To train the regression model, we transform the ground-truth center coordinates of optic disc and fovea of the IDRiD dataset to heatmaps using a 2D-Gaussian equation. The model is capable of pinpointing any single pixel in a vast 2D image space. The model is tested on IDRiD test dataset, Messidor, and G1020 datasets. The model outperforms the state-of-the-art methods on these datasets. The model is very robust and generic, which can be trained and used for the simultaneous localization of multiple landmarks in different medical image datasets. The full implementation code and the trained model with weights (based on Keras) are available for reuse at https://github.com/bhargav-jb/FundusPosNet.

This study quantified and compared phase retardation distribution in the central macula with the thickness of the Henle fiber layer (HFL). A scanning laser polarimeter (SLP) was used to acquire 20° × 40° macular-centered images, either with fixed corneal compensation or with variable corneal compensation, in two cohorts of clinically normal subjects (N = 36). Phase retardation maps from SLP imaging were used to generate a macular cross pattern (fixed compensation) or an annulus pattern (variable compensation) centered on the macula. Intensity profiles in the phase retardation maps were produced using annular regions of interest at eccentricities from 0.25° to 3°. Pixel intensity was averaged at each eccentricity, acting as a surrogate for macular phase retardation. Directional OCT images were acquired in the horizontal and vertical meridians in all subjects, allowing visualization of the HFL thickness. HFL thickness was manually segmented in each meridian and averaged. In both cohorts, phase retardation and HFL thickness were highly correlated in the central 3° assessed, providing further evidence that the source of the phase retardation signal in the central macula is dominated by the HFL and that the center of the macula on cross sectional imaging corresponds closely with the center of the macular cross on SLP imaging.

PurposeCones in diabetic patients are at risk due to metabolic and vascular changes. By imaging retinal vessel modeling at high magnification, we reduced its impact on cone distribution measurements. The retinal vessel images and retinal thickness measurements provided information about cone microenvironment.MethodsWe compared cone data in 10 diabetic subjects (28–78 yr) to our published norms from 36 younger and 10 older controls. All subjects were consented and tested in a manner approved by the Indiana University Institutional Review Board, which adhered to the Declaration of Helsinki. Custom adaptive optics scanning laser ophthalmoscopy (AOSLO) was used to image cones and retinal microcirculation. We counted cones in a montage of foveal and temporal retina, using four non-contiguous samples within 0.9–7 deg that were selected for best visibility of cones and least pathology. The data were fit with a two parameter exponential model: ln(cone density) = a * microns eccentricity + b. These results were compared to retinal thickness measurements from SDOCT.ResultsDiabetic cone maps were more variable than in controls and included patches, or unusually bright and dark cones, centrally and more peripherally. Model parameters and total cones within the central 14 deg of the macula differed across diabetic patients. Total cones fell into two groups: similar to normal for 5 vs. less than normal for 2 of 2 younger diabetic subjects and 3 older subjects, low but not outside the confidence limits. Diabetic subjects had all retinal vascular remodeling to varying degrees: microaneurysms; capillary thickening, thinning, or bends; and vessel elongation including capillary loops, tangles, and collaterals. Yet SD-OCT showed that no diabetic subject had a Total Retinal Thickness in any quadrant that fell outside the confidence limits for controls.ConclusionsAOSLO images pinpointed widespread retinal vascular remodeling in all diabetic eyes, but the SDOCT showed no increased retinal thickness. Cone reflectivity changes were found in all diabetic patients, but significantly low cone density in only some. These results are consistent with early changes to neural, glial, or vascular components of the retinal without significant retinal thickening due to exudation.

Foveal hypoplasia is the absence of a foveal depression and the presence of the ganglion cell layer in the foveola. A spectrum of clinical characteristics, including normal or variably decreased visual acuity, has been described in patients with blunted foveal contours. Multiple systemic and ophthalmologic conditions including albinism, aniridia, nanophthalmos, prematurity, and fovea plana have been associated with this anomaly. This article illustrates select clinical conditions characterized by a blunted foveal contour. Given the heterogeneity of findings, a thorough medical history and detailed physical and ocular examinations are usually sufficient for the clinician to make the correct diagnosis. [ABSTRACT FROM AUTHOR]

Purpose: Choriocapillaris insufficiency may play a role in centripetal retinitis pigmentosa (RP) progression involving the fovea. However, the relationship between choriocapillaris integrity and foveal damage in RP is unclear. We examined the relationship between choriocapillaris flow and the presence of foveal photoreceptor involvement in RP. Methods: We categorized the severity of central involvement in RP by the occurrence of foveal ellipsoid zone (EZ) disruption: present (severe RP) or absent (mild RP). Using optical coherence tomography angiography (OCTA, AngioVue, Optovue) in cases and unaffected age-matched controls, we compared vessel density (VD) between the groups using the generalized linear mixed model, controlling for age, gender, and scan quality. Results: Fifty-seven eyes (20 severe RP, 18 mild RP, and 19 controls) were included. Foveal and parafoveal mean outer retinal thickness (µm) were lower in severe RP (fovea: 101.3 ± 14.5; parafovea: 68.4 ± 11.7) than controls (fovea: 161.2 ± 8.9; parafovea: 142.1 ± 11.8; p ≤ 0.001) and mild RP (fovea: 162.0 ± 14.7; parafovea: 116.8 ± 29.4; p ≤ 0.0001). Foveal choriocapillaris VD (%) was lower in severe RP (56.7 ± 6.8) than controls (69.9 ± 4.6; p = 0.008) and mild RP (65.3 ± 5.3; p = 0.01). The parafoveal choriocapillaris VD was lower in severe RP than controls (64.4 ± 5.9 vs. 68.3 ± 4.1; p = 0.04) but no different than in mild RP (p = 0.4). Conclusion: Choriocapillaris flow loss was associated with fovea-involving photoreceptor damage in RP. Further research is warranted to validate this putative association and clarify causation. Choriocapillaris imaging using OCTA may provide information to supplement structural OCT findings when evaluating subjects with RP in neuroprotective or regenerative clinical trials. [ABSTRACT FROM AUTHOR]

Background: Pronounced asymmetric changes in ocular globe size during eye development have been observed in a number of species ranging from humans to lizards. In contrast, largely symmetric changes in globe size have been described for other species like rodents. We propose that asymmetric changes in the three‐dimensional structure of the developing eye correlate with the types of retinal remodeling needed to produce areas of high photoreceptor density. To test this idea, we systematically examined three‐dimensional aspects of globe size as a function of eye development in the bifoveated brown anole, Anolis sagrei. Results: During embryonic development, the anole eye undergoes dynamic changes in ocular shape. Initially spherical, the eye elongates in the presumptive foveal regions of the retina and then proceeds through a period of retraction that returns the eye to its spherical shape. During this period of retraction, pit formation and photoreceptor cell packing are observed. We found a similar pattern of elongation and retraction associated with the single fovea of the veiled chameleon, Chamaeleo calyptratus. Conclusions: These results, together with those reported for other foveated species, support the idea that areas of high photoreceptor packing occur in regions where the ocular globe asymmetrically elongates and retracts during development. Key Findings: The eyes of the brown anole, Anolis sagrei, and veiled chameleon, Chamaeleo calyptratus undergo dynamic asymmetrical changes in ocular shape during development.In both species, asymmetric elongation and retraction of the ocular globe is associated with fovea morphogenesis.Pit formation and photoreceptor cell packing in the foveal area occur when the corresponding region of the ocular globe is retracting relative to adjacent regions. [ABSTRACT FROM AUTHOR]

Abstract Background The pathogenesis of partial-thickness macular defects and the role of Müller glial cells in the development of such defects are not well understood. We document the morphological characteristics of various types of partial-thickness macular defects using spectral-domain optical coherence tomography, with the focus on tractional and degenerative lamellar holes, and discuss possible pathogenic mechanisms. Methods A retrospective case series of 61 eyes of 61 patients with different types of partial-thickness macular defects is described. Results Partial-thickness macular defects are caused by anteroposterior or tangential traction onto the fovea exerted by the partially detached posterior hyaloid and epiretinal membranes, respectively. Tractional elevation of the inner Müller cell layer of the foveola—without (outer lamellar holes, foveal pseudocysts) or with a disruption of this layer (tractional lamellar holes, macular pseudoholes)—produces an elevation of the inner layers of the foveal walls (nerve fiber layer to outer plexiform layer [OPL]) and a schisis between the OPL and Henle fiber layer (HFL). With the exception of outer lamellar holes, the (outer part of the) central outer nuclear layer and the external limiting membrane remain nondisrupted in the various types of partial-thickness defects. Degenerative lamellar holes are characterized by cavitations between the inner plexiform layer and HFL of the foveal walls; many cases have lamellar hole-associated epiretinal proliferation (LHEP). Proliferating cells of the disrupted Müller cell cone may contribute to the development of LHEP and fill the spaces left by degenerated photoreceptors in the foveal center. Conclusions It is suggested that morphological characteristics of partial-thickness macular defects can be explained by the disruption of the (stalk of the) Müller cell cone in the foveola and the location of tissue layer interfaces with low mechanical stability: the boundary with no cellular connections between both Müller cell populations in the foveola, and the interface between the OPL and HFL in the foveal walls and parafovea. We propose that the development of the cavitations in degenerative lamellar holes is initiated by traction which produces a schisis between the OPL and HFL, and enlarged by a slow and chronic degeneration of Henle fibers and bipolar cells. Trial registration retrospectively registered, #143/20-ek, 04/03/2020

Abstract Purpose Patients with center-involved diabetic macular edema (CI-DME) with good visual acuity (VA) represent a controversial clinical scenario in which a subthreshold laser might be a reasonable approach. We report a case series of patients with CI-DME with VA better than 20/32 who were treated with a subthreshold 577 nm (yellow) laser. Methods The area of retinal thickening on OCT was treated with confluent laser spots at individually titrated power. The fovea was spared from treatment. Effectiveness and safety were evaluated through OCT and autofluorescence (AF) as well as BCVA. Results A total of 23 eyes from 19 patients were treated. VA ranged from 20/20 to 20/30. The follow-up period ranged from 6 to 18 months. Edema in OCT resolved completely at the end of follow-up in 56.5% (13/23) of the cases. Central retinal thickness was reduced at 12 weeks and at the end of follow-up, with a mean reduction of 16.9 μm and 22 μm, respectively (paired t-test p = 0.001 and 0.0003). VA remained stable. The laser was invisible (OCT, AF, Fundoscopy) in 91,3% (21/23) of eyes. Conclusions A fovea-sparing yellow subthreshold laser was safe and effective for treating CI-DME patients with good VA in this case series. This technique is of interest to prevent the progression of mild edema and might avoid or reduce the use of more invasive and expensive therapies. Excluding the fovea from the treated area does not seem to affect the results, which is of interest to novel laser practitioners.

Purpose: To investigate the effects of refraction on retinal thickness measurements at different locations and layers in healthy eyes of Saudi participants. Methods: Thirty-six randomly selected adults aged 27.0 ± 5.7 years who attended a Riyadh hospital from 2016 to 2017 were categorized into three groups: non-myopic (spherical equivalent refraction [SER], +1.00 to –0.50 diopters [D]), low myopic (SER, –0.75 to –3.00D), and moderate to high myopic (SER ≤ –3.25D). Full, inner, and outer retinal thicknesses were measured at nine locations by spectral-domain stratus optical coherence tomography (Optovue Inc., Fremont, CA, USA) and were compared according to refractive group and sex. Results: The mean SERs for the non-myopia, low myopia, and moderate to high myopia groups were 0.2 ± 0.6, –1.5 ± 0.5, and –7.5 ± 1.9 D, respectively. Refractive error, but not sex, had significant effects on the retinal layer thickness measurements at different locations (P < 0.05). The parafoveal and outer retinal layers were significantly thicker than the perifoveal and inner retina layers in all groups (P < 0.05). The full foveal thickness was higher and the full parafoveal and perifoveal regions were thinner in moderate to high myopic eyes than in the non-myopic eyes (P < 0.05), but were similar to those in the low myopic eyes (P > 0.05). The foveal thicknesses measured in the inner and outer layers of the retina were higher but the thicknesses measured at the inner and outer layers of the parafoveal and perifoveal regions were lower in moderate to high myopic eyes. Conclusion: There were regional differences in the retinal layer thicknesses of healthy Saudi eyes, which was dependent on the central refractions. This is important when interpreting retinal nerve fiber layer thicknesses in myopia and disease management in Saudi participants.

AIM: To describe using spectral-domain optical coherence tomography the regeneration of the foveal morphology after pars plana (re)vitrectomy surgery and gas tamponade combined with injection of autologous platelet concentrate to treat full-thickness macular holes, and to describe different anatomical outcome. METHODS: A retrospective case series of 8 eyes of 8 patients was described. RESULTS: In all cases investigated, the platelet-assisted closure of macular holes was associated with a rapid resolution of cystic cavities in the foveal walls. In two patients, there was a regular regeneration of the foveal morphology after hole closure; the regenerated central fovea had a regular structure with a foveola and photoreceptors. In three other patients, there was an irregular regeneration of the fovea; a foveola was not formed, photoreceptor cells were absent from the foveal center, and the center was composed of Müller and retinal pigment epithelial (RPE) cells. The foveal regeneration after hole closure may proceed with or without a temporary detachment of the foveal center from the RPE, and with or without a direct contact between the central outer nuclear layer (ONL) and the RPE. Contacts between the ONL and RPE were observed only in patients with an irregular foveal regeneration after hole closure. CONCLUSION: The data show that there are different modes of foveal regeneration after closure of macular holes with (re)vitrectomy and platelet concentrate. It is suggested that the regular regeneration of the foveal morphology proceeds by Müller cell-mediated tissue movements without cell proliferation, whereas the irregular foveal regeneration proceeds in part by proliferation of Müller and RPE cells.

Diabetic retinopathy affects some parts of the retina, including the fovea, as it progresses to the severe stage. However, the relationship between the fovea and diabetic retinopathy progression remains unknown. Here, a new methodology is proposed to analyze the relationship between the fovea morphology and diabetic retinopathy progression. The procedure is built in four phases. First, data preparation is performed. In the second part, a deep learning model for diabetic retinopathy classification is developed. Subsequently, a score for every pixel in retinal images that map its contribution to the classification result is generated using the Local Interpretable Model-Agnostic Explanation (LIME). Finally, the generated scores are analyzed to obtain the most contributing retinal parts to the diagnosis. Our framework is developed and evaluated on retinal images from the IDRiD dataset. The advantages of our methodology are two-fold. First, our classifier correctly diagnoses diabetic retinopathy with an average accuracy of >75%, better than the state-of-the-art algorithms. Moreover, our framework reveals that the fovea areas have moderate contributions to the classification result through extensive analyses using LIME. Hence, more distinctive features like retinal lesions are probably required to build a robust classification and grading system.

Abstract Background Diabetic retinopathy (DR) is the leading cause of blindness in type 1 Diabetes Mellitus (DM) patients, as a consequence of impaired blood flow in the retina. Optical coherence tomography angiography (OCTA) is a newly developed, non-invasive, retinal imaging technique that permits adequate delineation of the perifoveal vascular network. It allows the detection of paramacular areas of capillary non perfusion and/or enlargement of the foveal avascular zone (FAZ), representing an excellent tool for assessment of DR. The relationship of these microvascular changes with systemic factors such as metabolic control or duration of the disease still needs to be elucidated. Methods Prospective, consecutive, large-scale OCTA study. A complete ocular examination including a comprehensive series of OCTA images of different scan sizes captured with 2 OCT devices (Cirrus HD-OCT, Carl Zeiss Meditec, Dublin, CA, USA, and Triton Deep Range Imaging OCT, Topcon Corp, Topcon, Japan) will be obtained as part of the yearly routine follow up visits in type 1 DM patients seen in the Diabetes Unit of the Endocrinology department which give written informed consent to participate in the project. The aim of this study is to investigate the relationship between OCTA-derived parameters and systemic factors, as metabolic control (Hb1Ac, lipid profile, cholesterol, etc), and other relevant clinical factors as demographics or duration of the disease. Discussion This study is directed to investigate the relationship between the status of the perifoveal vascular network and systemic markers of the disease, and in particular to study whether these changes reflect those occurring elsewhere in the body affected by diabetic microvascular disease, as the kidneys or the brain. If these relationships were demonstrated, early detection of these microvascular changes by OCTA could lead to modifications in the pharmacological management of type 1 diabetic patients, as a way to reduce the risk of future complications in both the eye and other organs. Trial registration ClinicalTrials.gov, trial number NCT03422965.

Background: Prior studies have suggested that subclinical retinal abnormalities may be present in aquaporin-4 immunoglobulin G (AQP4-IgG) seropositive neuromyelitis optica spectrum disorder (NMOSD), in the absence of a clinical history of optic neuritis (ON). Objective: Our aim was to compare retinal layer thicknesses at the fovea and surrounding macula between AQP4-IgG+ NMOSD eyes without a history of ON (AQP4-nonON) and healthy controls (HC). Methods: In this single-center cross-sectional study, 83 AQP4-nonON and 154 HC eyes were studied with spectral-domain optical coherence tomography (OCT). Results: Total foveal thickness did not differ between AQP4-nonON and HC eyes. AQP4-nonON eyes exhibited lower outer nuclear layer (ONL) and inner photoreceptor segment (IS) thickness at the fovea (ONL: −4.01 ± 2.03 μm, p = 0.049; IS: −0.32 ± 0.14 μm, p = 0.029) and surrounding macula (ONL: −1.98 ± 0.95 μm, p = 0.037; IS: −0.16 ± 0.07 μm, p = 0.023), compared to HC. Macular retinal nerve fiber layer (RNFL: −1.34 ± 0.51 μm, p = 0.009) and ganglion cell + inner plexiform layer (GCIPL: −2.44 ± 0.93 μm, p = 0.009) thicknesses were also lower in AQP4-nonON compared to HC eyes. Results were similar in sensitivity analyses restricted to AQP4-IgG+ patients who had never experienced ON in either eye. Conclusions: AQP4-nonON eyes exhibit evidence of subclinical retinal ganglion cell neuronal and axonal loss, as well as structural evidence of photoreceptor layer involvement. These findings support that subclinical anterior visual pathway involvement may occur in AQP4-IgG+ NMOSD. [ABSTRACT FROM AUTHOR]

Purpose: Premature birth, race, and sex are contributing risk factors for retinopathy of prematurity (ROP) and have long-term impact on children's retinal structure. Few studies investigate impact of race and sex on macular structure in children born preterm. This study compared foveal structure in preterm and full-term children. Methods: Children aged 4–18 years were enrolled into three groups: (1) ROP-risk group (n = 81), born at < 32 weeks gestational age with and without history of ROP; (2) preterm group (n = 46), born at 32–36 weeks gestational age; and (3) control group (n = 68) with full-term birth. Using spectral-domain optical coherence tomography volume-scan images, foveal structure within 1-mm and 3-mm early treatment diabetic retinopathy study circular grid was measured and segmented. Total inner and outer retina thickness of the right eye was compared among the three groups. Results: The mean total foveal thickness (in microns) was 287 ± 26 for the ROP-risk group, 276 ± 19 for the preterm group, and 263 ± 20 for the control group (F = 26, p < 0.001). Foveal thickness of the ROP-risk group was significantly higher than that of the preterm group and the control group (all p < 0.05). Foveal thickness was thinner in black children than in white children and thinner in females than in males (all p < 0.001). A similar disparity in race and sex was found in the thickness of the inner and outer layers. Conclusions: The fovea was significantly thicker in the ROP-risk group than the control group. Foveal thickness decreases with increased gestational age. Race and sex are significant factors in foveal structure in children. [ABSTRACT FROM AUTHOR]

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 gazecontingent 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. [ABSTRACT FROM AUTHOR]

Background: To assess the normal retina of the pigeon eye using spectral domain optical coherence tomography (SD-OCT) and establish a normative reference. Methods: Twelve eyes of six ophthalmologically normal pigeons (Columba livia) were included. SD-OCT images were taken with dilated pupils under sedation. Four meridians, including the fovea, optic disc, red field, and yellow field, were obtained in each eye. The layers, including full thickness (FT), ganglion cell complex (GCC), thickness from the retinal pigmented epithelium to the outer nuclear layer (RPE-ONL), and from the retinal pigmented epithelium to the inner nuclear layer (RPE-INL), were manually measured. Results: The average FT values were significantly different among the four meridians (p < 0.05), with the optic disc meridian being the thickest (294.0 ± 13.9 µm). The average GCC was thickest in the optic disc (105.3 ± 27.1 µm) and thinnest in the fovea meridian (42.8 ± 15.3 µm). The average RPE-INL of the fovea meridian (165.5 ± 18.3 µm) was significantly thicker than that of the other meridians (p < 0.05). The average RPE-ONL of the fovea, optic disc, yellow field, and red field were 91.2 ± 5.2 µm, 87.7 ± 5.3 µm, 87.6 ± 6.5 µm, and 91.4 ± 3.9 µm, respectively. RPE-INL and RPE-ONL thickness of the red field meridian did not change significantly with measurement location (p > 0.05). Conclusions: Measured data could be used as normative references for diagnosing pigeon retinopathies and further research on avian fundus structure. [ABSTRACT FROM AUTHOR]

In the vertebrate retina, amacrine and ganglion cells represent the most diverse cell classes. They can be classified into different cell types by several features, such as morphology, light responses, and gene expression profile. Although birds possess high visual acuity (similar to primates that we used here for comparison) and tetrachromatic color vision, data on the expression of transcription factors in retinal ganglion cells of birds are largely missing. In this study, we tested various transcription factors, known to label subpopulations of cells in mammalian retinae, in two avian species: the common buzzard (Buteo buteo), a raptor with exceptional acuity, and the domestic pigeon (Columba livia domestica), a good navigator and widely used model for visual cognition. Staining for the transcription factors Foxp2, Satb1 and Satb2 labeled most ganglion cells in the avian ganglion cell layer. CtBP2 was established as marker for displaced amacrine cells, which allowed us to reliably distinguish ganglion cells from displaced amacrine cells and assess their densities in buzzard and pigeon. When we additionally compared the temporal and central fovea of the buzzard with the fovea of primates, we found that the cellular organization in the pits was different in primates and raptors. In summary, we demonstrate that the expression of transcription factors is a defining feature of cell types not only in the retina of mammals but also in the retina of birds. The markers, which we have established, may provide useful tools for more detailed studies on the retinal circuitry of these highly visual animals. [ABSTRACT FROM AUTHOR]

Purpose: To compare foveal hypoplasia and the appearance of the ellipsoid zone (EZ) at the fovea in patients with genetically confirmed achromatopsia (ACHM) and blue cone monochromacy (BCM). Design: Retrospective, multicenter observational study. Participants: Molecularly confirmed patients with ACHM (n = 89) and BCM (n = 33). Methods: We analyzed high-resolution spectral-domain OCT (SD-OCT) images of the macula from patients with BCM. Three observers independently graded SD-OCT images for foveal hypoplasia (i.e., retention of ≥1 inner retinal layers at the fovea), and 4 observers judged the integrity of the EZ at the fovea, based on an established grading scheme. These measures were compared with previously published data from the patients with ACHM. Main Outcome Measures: Presence of foveal hypoplasia and EZ grade. Results: Foveal hypoplasia was significantly more prevalent in ACHM than in BCM (P < 0.001). In addition, we observed a significant difference in the distribution of EZ grades between ACHM and BCM, with grade II EZ being by far the most common phenotype in BCM (61% of patients). In contrast, patients with ACHM had a relatively equal prevalence of EZ grades I, II, and IV. Grade IV EZ was 2.6 times more prevalent in ACHM compared with BCM, whereas grade V EZ (macular atrophy) was present in 3% of both the ACHM and BCM cohorts. Conclusions: The higher incidence of foveal hypoplasia in ACHM than BCM supports a role for cone activity in foveal development. Although there are differences in EZ grades between these conditions, the degree of overlap suggests EZ grade is not sufficient for definitive diagnosis, in contrast to previous reports. Analysis of additional OCT features in similar cohorts may reveal differences with greater diagnostic value. Finally, the extent to which foveal hypoplasia or EZ grade is prognostic for therapeutic potential in either group remains to be seen, but motivates further study.