Search

Identification of retinal diseases in automated screening methods, such as those used in clinical settings or computer-aided diagnosis, usually depends on the localization and segmentation of the Optic Disc (OD) and fovea. However, this task is difficult since these anatomical features have irregular spatial, texture, and shape characteristics, limited sample sizes, and domain shifts due to different data distributions across datasets. This study proposes a novel Multiresolution Cascaded Attention U-Net (MCAU-Net) model that addresses these problems by optimally balancing receptive field size and computational efficiency. The MCAU-Net utilizes two skip connections to accurately localize and segment the OD and fovea in fundus images. We incorporated a Multiresolution Wavelet Pooling Module (MWPM) into the CNN at each stage of U-Net input to compensate for spatial information loss. Additionally, we integrated a cascaded connection of the spatial and channel attentions as a skip connection in MCAU-Net to concentrate precisely on the target object and improve model convergence for segmenting and localizing OD and fovea centers. The proposed model has a low parameter count of 0.8 million, improving computational efficiency and reducing the risk of overfitting. For OD segmentation, the MCAU-Net achieves high IoU values of 0.9771, 0.945, and 0.946 for the DRISHTI-GS, DRIONS-DB, and IDRiD datasets, respectively, outperforming previous results for all three datasets. For the IDRiD dataset, the MCAU-Net locates the OD center with an Euclidean Distance (ED) of 16.90 pixels and the fovea center with an ED of 33.45 pixels, demonstrating its effectiveness in overcoming the common limitations of state-of-the-art methods. [ABSTRACT FROM AUTHOR]

Abstract Identification of retinal diseases in automated screening methods, such as those used in clinical settings or computer-aided diagnosis, usually depends on the localization and segmentation of the Optic Disc (OD) and fovea. However, this task is difficult since these anatomical features have irregular spatial, texture, and shape characteristics, limited sample sizes, and domain shifts due to different data distributions across datasets. This study proposes a novel Multiresolution Cascaded Attention U-Net (MCAU-Net) model that addresses these problems by optimally balancing receptive field size and computational efficiency. The MCAU-Net utilizes two skip connections to accurately localize and segment the OD and fovea in fundus images. We incorporated a Multiresolution Wavelet Pooling Module (MWPM) into the CNN at each stage of U-Net input to compensate for spatial information loss. Additionally, we integrated a cascaded connection of the spatial and channel attentions as a skip connection in MCAU-Net to concentrate precisely on the target object and improve model convergence for segmenting and localizing OD and fovea centers. The proposed model has a low parameter count of 0.8 million, improving computational efficiency and reducing the risk of overfitting. For OD segmentation, the MCAU-Net achieves high IoU values of 0.9771, 0.945, and 0.946 for the DRISHTI-GS, DRIONS-DB, and IDRiD datasets, respectively, outperforming previous results for all three datasets. For the IDRiD dataset, the MCAU-Net locates the OD center with an Euclidean Distance (ED) of 16.90 pixels and the fovea center with an ED of 33.45 pixels, demonstrating its effectiveness in overcoming the common limitations of state-of-the-art methods.

Abstract Documenting the organization of the retinal capillaries is of importance to understand the visual consequences of vascular diseases which may differentially affect the microvascular layers. Here we detailed the spatial organization of the macular capillaries in ten healthy human subjects using a prototypic adaptive optics-enhanced optical coherence tomography angiography (AO-OCTA) system. Within the central 6° × 6°, the radial peripapillary capillaries and the superficial, intermediate and deep vascular plexuses (SVP, IVP and DVP, respectively) were consistently resolved. In 8 out of the 10 eyes, the capillary segments composing the perifoveal arcade (PFA) were perfused only by the SVP, while drainage of the PFA showed more variability, comprising a case in which the PFA was drained by the DVP. Around the center, a distinct central avascular zone could be documented for each layer in 7 of the 10 cases; in three eyes, the IVP and SVP merged tangentially around the center. In all eyes, the foveal avascular zone was larger in the DVP than in the SVP and IVP. In one eye with incomplete separation of the inner foveal layers, there was continuity of both the SVP and the IVP; a central avascular zone was only present in the DVP. The diversity of perfusion and drainage patterns supported a connectivity scheme combining parallel and serial organizations, the latter being the most commonly observed in perifoveal vessels. Our results thus help to further characterize the diversity of organization patterns of the macular capillaries and to robustly analyze the IVP, which will help to characterize early stages of microvascular diseases.

The fovea of the human retina, a specialization for acute and color vision, features a high concentration of cone photoreceptors. A pit on the inner retinal aspect is created by the centrifugal migration of post-receptoral neurons. Foveal cells are specified early in fetal life, but the fovea reaches its final configuration postnatally. Pre-term birth retards migration resulting in a small pit, a small avascular zone, and nearly continuous inner retinal layers. To explore the involvement of Müller glia, we used serial-section electron microscopic reconstructions to examine the morphology and neural contacts of Müller glia contacting a single foveal cone in a 28-year-old male organ donor born at 28 weeks of gestation. A small nondescript foveal avascular zone contained massed glial processes that included a novel class of 'inner' Müller glia. Similar to classic 'outer' Müller glia that span the retina, inner Müller glia have bodies in the inner nuclear layer (INL). These cells are densely packed with intermediate filaments and insert processes between neurons. Unlike 'outer' Müller glia, 'inner' Müller glia do not reach the external limiting membrane but instead terminate at the outer plexiform layer. One completely reconstructed inner cell ensheathed cone pedicles and a cone-driven circuit of midget bipolar and ganglion cells. Inner Müller glia outnumber foveal cones by 1.8-fold in the outer nuclear layer (221,448 vs. 123,026 cells/mm²). Cell bodies of inner Müller glia outnumber those of outer Müller glia by 1.7-fold in the INL (41,872 vs. 24,631 cells/ mm²). Müller glia account for 95 and 80% of the volume of the foveal floor and Henle fiber layer, respectively. Determining whether inner cells are anomalies solely resulting from retarded lateral migration of inner retinal neurons in pre-term birth requires further research. [ABSTRACT FROM AUTHOR]

Documenting the organization of the retinal capillaries is of importance to understand the visual consequences of vascular diseases which may differentially affect the microvascular layers. Here we detailed the spatial organization of the macular capillaries in ten healthy human subjects using a prototypic adaptive optics-enhanced optical coherence tomography angiography (AO-OCTA) system. Within the central 6° × 6°, the radial peripapillary capillaries and the superficial, intermediate and deep vascular plexuses (SVP, IVP and DVP, respectively) were consistently resolved. In 8 out of the 10 eyes, the capillary segments composing the perifoveal arcade (PFA) were perfused only by the SVP, while drainage of the PFA showed more variability, comprising a case in which the PFA was drained by the DVP. Around the center, a distinct central avascular zone could be documented for each layer in 7 of the 10 cases; in three eyes, the IVP and SVP merged tangentially around the center. In all eyes, the foveal avascular zone was larger in the DVP than in the SVP and IVP. In one eye with incomplete separation of the inner foveal layers, there was continuity of both the SVP and the IVP; a central avascular zone was only present in the DVP. The diversity of perfusion and drainage patterns supported a connectivity scheme combining parallel and serial organizations, the latter being the most commonly observed in perifoveal vessels. Our results thus help to further characterize the diversity of organization patterns of the macular capillaries and to robustly analyze the IVP, which will help to characterize early stages of microvascular diseases. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to investigate the preoperative and postoperative change in retinal sensitivity in relation to the distance to the retinal detachment (RD) in patients with fovea‐on RD. Methods: We prospectively evaluated 13 patients with fovea‐on RD and a healthy control eye. Preoperatively, OCT scans of the RD border and the macula were obtained. The RD border was highlighted on the SLO image. Microperimetry was used to assess the retinal sensitivity at the macula, the RD border and the retina around the RD border. At 6 weeks, 3 and 6 months postoperatively, follow‐up examinations of OCT and microperimetry were performed in the study eye. Microperimetry was performed once in control eyes. Microperimetry data were overlaid on the SLO image. The shortest distance to the RD border was calculated for each sensitivity measurement. The change in retinal sensitivity was calculated as control‐study. The relation between the change in retinal sensitivity and the distance to the RD border was assessed using a locally weighted scatterplot smoothing curve. Results: Preoperatively, the greatest loss in retinal sensitivity was 21 dB at 3° inside the RD which decreased linearly, through the RD border, and reached a plateau of 2 dB at 4°. For 6 weeks and 3 months postoperatively, the greatest retinal sensitivity loss remained at 3° inside the RD but was 4 dB and sensitivity loss decreased linearly to a plateau of 0 dB at 5° outside the RD. At 6 months postoperatively, the greatest sensitivity loss was 2 dB at 3° inside the RD, and decreased linearly to a plateau of 0 dB at 2° outside the RD. Conclusions: Retinal damage extends beyond the detached retina. Retinal sensitivity loss of the attached retina decreased drastically as the distance to the RD increased. Postoperative recovery occurred for both attached and detached retina. [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.

In primates, high-acuity vision is mediated by the fovea, a small specialized central region of the retina. The fovea, unique to the anthropoid lineage among mammals, undergoes notable neuronal morphological changes during postnatal maturation. However, the extent of cellular similarity across anthropoid foveas and the molecular underpinnings of foveal maturation remain unclear. Here, we used high-throughput single-cell RNA sequencing to profile retinal cells of the common marmoset (Callithrix jacchus), an early divergent in anthropoid evolution from humans, apes, and macaques. We generated atlases of the marmoset fovea and peripheral retina for both neonates and adults. Our comparative analysis revealed that marmosets share almost all their foveal types with both humans and macaques, highlighting a conserved cellular structure among primate foveas. Furthermore, by tracing the developmental trajectory of cell types in the foveal and peripheral retina, we found distinct maturation paths for each. In-depth analysis of gene expression differences demonstrated that cone photoreceptors and Müller glia (MG), among others, show the greatest molecular divergence between these two regions. Utilizing single-cell ATAC-seq and gene-regulatory network inference, we uncovered distinct transcriptional regulations differentiating foveal cones from their peripheral counterparts. Further analysis of predicted ligand-receptor interactions suggested a potential role for MG in supporting the maturation of foveal cones. Together, these results provide valuable insights into foveal development, structure, and evolution. [ABSTRACT FROM AUTHOR]

Identification of the optic disc and fovea is crucial for automating the diagnosis and screening of retinal diseases. Based on quantitative calculations, this study presents a decision support system for doctors that automatically detect optic nerve hypoplasia. For disease diagnosis, U-Net architecture is used, which uses a pre-trained ResNet encoder to segment the optic disc and fovea structures. An important aspect of the proposed technique is that pretrained ResNet and U-Net are used together, providing robust performance in the detection of optic nerve hypoplasia. Our proposed architecture was tested on retinal images from Messidor, Diaretdb1, DRIVE, HRF, APTOS, and IDRID. In addition, a special database called ONH-NET was created based on 189 retinal images obtained from Düzce University, Department of Ophthalmology. Messidor database test images showed, 0. 9069 IOU Score, 0.9626 Sensitivity, 0.9411 Precision, 0.9974 Accuracy and 0.9505 dice-coefficient values in optic disc detection, and 0.8282 IOU score, 0.8442 sensitivity, 0.8252 precision, 0.8992 Accuracy, 0.7873 dice coefficient values were obtained in fovea detection. We computed diameter optic disc to macula radius ratios from segmented optic disc and fovea for screening optic nerve hypoplasia and achieved 100% success. [ABSTRACT FROM AUTHOR]

The fovea of the human retina, a specialization for acute and color vision, features a high concentration of cone photoreceptors. A pit on the inner retinal aspect is created by the centrifugal migration of post-receptoral neurons. Foveal cells are specified early in fetal life, but the fovea reaches its final configuration postnatally. Pre-term birth retards migration resulting in a small pit, a small avascular zone, and nearly continuous inner retinal layers. To explore the involvement of Müller glia, we used serial-section electron microscopic reconstructions to examine the morphology and neural contacts of Müller glia contacting a single foveal cone in a 28-year-old male organ donor born at 28 weeks of gestation. A small non-descript foveal avascular zone contained massed glial processes that included a novel class of ‘inner’ Müller glia. Similar to classic ‘outer’ Müller glia that span the retina, inner Müller glia have bodies in the inner nuclear layer (INL). These cells are densely packed with intermediate filaments and insert processes between neurons. Unlike ‘outer’ Müller glia, ‘inner’ Müller glia do not reach the external limiting membrane but instead terminate at the outer plexiform layer. One completely reconstructed inner cell ensheathed cone pedicles and a cone-driven circuit of midget bipolar and ganglion cells. Inner Müller glia outnumber foveal cones by 1.8-fold in the outer nuclear layer (221,448 vs. 123,026 cells/mm2). Cell bodies of inner Müller glia outnumber those of outer Müller glia by 1.7-fold in the INL (41,872 vs. 24,631 cells/ mm2). Müller glia account for 95 and 80% of the volume of the foveal floor and Henle fiber layer, respectively. Determining whether inner cells are anomalies solely resulting from retarded lateral migration of inner retinal neurons in pre-term birth requires further research.

Purpose: To report a case of a refractory foveal microaneurysm (MA) that was successfully treated by use of a new surgical procedure. Observations: This study involved a 79-year-old female with an active foveal MA associated with branch retinal vein occlusion in her left eye. Despite anti-vascular endothelial growth factor treatments, the MA remained active without closure, and best-corrected visual acuity (VA) gradually decreased from 20/20 to 20/200. After our new surgical procedure was explained in detail to the patient, written informed consent was obtained from the patient and the surgery was performed. Briefly, following pars plana vitrectomy, the internal limiting membrane in her left eye was peeled and the retina of the external wall of the MA was then gently incised. The exposed MA was then directly grabbed and pulled up onto the retina using 27-gauge microforceps, and photocoagulation was performed. At 3-months postoperative, closure of the MA and improvement in the retinal findings were observed, and best-corrected VA improved to 20/67. Conclusions and importance: We report a case of a refractory foveal MA that was successfully treated with a novel surgical technique that closed the MA, avoided thermal damage to the surrounding tissue, and resulted in improved postoperative VA.

Aims: To measure the foveal pit morphology parameters and evaluate their correlations with age and sex. Settings and Design: A retrospective cross-sectional matched comparison study in a tertiary center. Methods and Materials: Forty men and 40 age-matched women who had normal macular structures and foveal contours were enrolled. Foveal pit parameters including top width, base width, nasal width, temporal width, minimal thickness, nasal thickness, temporal thickness, nasal height, temporal height, nasal slope, and temporal slope were measured on horizontal B-scan macular optical coherence tomography and compared between men and women. Statistical Analysis Used: Paired t-tests and Pearson's correlation analysis. Results: The average patient age was 51.4 ± 17.5 (21–84) years. Women had a wider base width (313.1 ± 68.0 μm vs 266.8 ± 70.9 μm, P = 0.006), wider temporal width (1043.1 ± 245.6 μm vs 968.9 ± 261.0 μm, P = 0.006), thinner nasal thickness (345.6 ± 36.2 μm vs 359.7 ± 35.8 μm, P = 0.048), and flatter temporal slope (11.60 ± 2.52° vs 12.98 ± 2.68°, P = 0.016) than men. With age, the base width (r = 0.35, P = 0.025) and temporal width (r = 0.54, P = 0.0003) tended to be wider and the temporal slope was flatter (r = -0.45, P = 0.003) in women but not men. The minimal thickness tended to be thinner in the elderly group (r = 0.038, P = 0.015). Conclusions: Women had a significantly wider base width, wider temporal width, thinner nasal thickness, and flatter temporal slope of the foveal pit than age-matched men. The base width and temporal width were wider and the temporal slope was flatter with age in women but not men.

Objectives: This study aimed to examine the choroidal thicknesses (ChT) changes before and after resolution of subretinal fluid in patients with central serous chorioretinopathy (CSR) and in their fellow eyes. Materials and Methods: Patients with acute CSR were studied and followed until subretinal fluid resolved. Sixty-eight eyes from 34 CSR cases (24 men and 10 women, mean age of 37.34±6.2, range 27-50) were examined. Their ChT was measured using enhanced depth imaging optical coherence tomography (EDI-OCT). Imaging repeated after sub-retinal fluid resolution. ChT changes were analyzed before and after the resolution of subretinal fluid in both eyes. Results: Mean ChTs in CSR eyes were 387±97 µm, 414±97 µm, and 384±87 µm in 1 mm temporally away from the center, central sub-fovea, and 1 mm nasally away from the center, respectively; and those in the fellow eyes were 283±55 µm, 303±60 µm, and 282±56 µm in the same order. ChT decreased significantly (P≤0.001) to 305±82 µm, 334±86 µm, and 313±76 µm in CSR eyes and to 242±52 µm, 262±55 µm, and 246±48 µm in contralateral eyes in the temporal, central sub-foveal, and nasal sequences after subretinal fluid resolution, respectively. There was a strong correlation between the ChT in active phase and the ChT in resolved phase in both affected and fellow eyes. There was no detectable correlation between central sub-foveal fluid height and sub-foveal choroidal thickness in the affected and fellow eye (P=0.23). Conclusion: Nasal and temporal comparison of the affected and fellow eyes before and after fluid resolution showed that the nasal choroid was thinner than temporal choroid (as the average population) in active phase. In the resolution phase, however, it was the temporal choroid that was thinner than the nasal choroid, and the resolution pattern was not asymmetric.

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.

The terms fossa and fovea are found in Terminologia Anatomica, however, there is no clear difference between both terms. Therefore, the objective of this study was to determine the coherence between the lexical, morphological and etymological relationship of the term's fossa and fovea with their use in Terminologia Anatomica. The terms fossa and fovea were consulted in Terminologia Anatomica (Federative International Programme for Anatomical Terminology, 2019) and in International Anatomical Terminology (Federative Committee on Anatomical Terminology, 2001). Subsequently, a search for both terms was carried out in Latin-Spanish and English-Latin dictionaries. Finally, the terms fossa and fovea were consulted in the Diccionario de la Real Academia Española and in the Diccionario panhispánico de términos médicos de la Real Academia Nacional de Medicina de España to know the definitions in the medical area. The search reported that the term "fossa" comes from the Latin fossa, which means "excavation, ditch, ditch; hole, hole." For its part, "fovea" comes from the Latin fovea, which means "small hole." Therefore, the difference between fossa and fovea is determined by their size according to their definitions. However, in Terminologia Anatomica, structures have been described with the diminutive of fossa and fovea, which makes the differentiation of the terms according to their size more complex. Furthermore, the lack of unification in the nomenclature between fossa, fovea and their diminutives generates great confusion and inconsistencies in the translations from Latin to English and Spanish in Terminologia Anatomica that reduce the precision of the nomenclature. Therefore, we propose the unification of the terms fossa and fovea based on the size of the anatomical depression and clarify their translation into English and Spanish. [ABSTRACT FROM AUTHOR]

Aims: To measure the foveal pit morphology parameters and evaluate their correlations with age and sex. Settings and Design: A retrospective cross-sectional matched comparison study in a tertiary center. Methods and Materials: Forty men and 40 age-matched women who had normal macular structures and foveal contours were enrolled. Foveal pit parameters including top width, base width, nasal width, temporal width, minimal thickness, nasal thickness, temporal thickness, nasal height, temporal height, nasal slope, and temporal slope were measured on horizontal B-scan macular optical coherence tomography and compared between men and women. Statistical Analysis Used: Paired t-tests and Pearson's correlation analysis. Results: The average patient age was 51.4 ± 17.5 (21–84) years. Women had a wider base width (313.1 ± 68.0 μm vs 266.8 ± 70.9 μm, P = 0.006), wider temporal width (1043.1 ± 245.6 μm vs 968.9 ± 261.0 μm, P = 0.006), thinner nasal thickness (345.6 ± 36.2 μm vs 359.7 ± 35.8 μm, P = 0.048), and flatter temporal slope (11.60 ± 2.52° vs 12.98 ± 2.68°, P = 0.016) than men. With age, the base width (r = 0.35, P = 0.025) and temporal width (r = 0.54, P = 0.0003) tended to be wider and the temporal slope was flatter (r = -0.45, P = 0.003) in women but not men. The minimal thickness tended to be thinner in the elderly group (r = 0.038, P = 0.015). Conclusions: Women had a significantly wider base width, wider temporal width, thinner nasal thickness, and flatter temporal slope of the foveal pit than age-matched men. The base width and temporal width were wider and the temporal slope was flatter with age in women but not men. [ABSTRACT FROM AUTHOR]

PurposeTo characterize the effect of sampling window size on maps of foveal cone density derived from adaptive optics scanning light ophthalmoscope (AOSLO) images of the cone mosaic.MethodsForty-four AOSLO-derived montages of the foveal cone mosaic (300 x 300µm) were used for this study (from 44 individuals with normal vision). Cone photoreceptor coordinates were semi-automatically identified by one experienced grader. From these coordinates, cone density matrices across each foveal montage were derived using 10 different sampling window sizes containing 5, 10, 15, 20, 40, 60, 80, 100, 150, or 200 cones. For all 440 density matrices, we extracted the location and value of peak cone density (PCD), the cone density centroid (CDC) location, and cone density at the CDC.ResultsAcross all window sizes, PCD values were larger than those extracted at the CDC location, though the difference between these density values decreased as the sampling window size increased (p

Purpose: To describe the mechanisms of postoperative foveal restoration in three patients with bacillary layer detachment (BALAD) associated with macula-off rhegmatogenous retinal detachment. Observations: BALAD associated with macula-off rhegmatogenous retinal detachment presented with two different morphologies: with an intact foveal roof (case 1) and lamellar, with an open foveal roof (cases 2 and 3). In case 1 visual acuity significantly improved and foveal morphology completely restored at postoperative month 6, with a marked increase in foveal thickness. Case 2 presented with a lamellar BALAD in a long-standing retinal detachment, and it was treated with scleral buckling with an unfavourable evolution into a full-thickness hole in the early postoperative period. It was then addressed with internal limiting membrane peeling and inverted flap, which resulted in the resolution of the lesion, but with limited postoperative visual and anatomical recovery. Case 3 lamellar BALAD was directly addressed with pars plana vitrectomy, ILM peeling and inverted flap, with a remarkable foveal anatomical restoration and visual acuity improvement over the follow-up period. Conclusions and importance: The process of foveation may play a key role in the healing process of BALAD associated with rhegmatogenous retinal detachment. Lamellar BALAD should be considered and treated as a FTMH associated with retinal detachment. The two BALAD subtypes may represent different clinical stages of the BALAD spectrum.

The increase of brain neuron number in relation with brain size is currently considered to be the major evolutionary path to high cognitive power in amniotes. However, how changes in neuron density did contribute to the evolution of the information-processing capacity of the brain remains unanswered. High neuron densities are seen as the main reason why the fovea located at the visual center of the retina is responsible for sharp vision in birds and primates. The emergence of foveal vision is considered as a breakthrough innovation in visual system evolution. We found that neuron densities in the largest visual center of the midbrain – i.e., the optic tectum – are two to four times higher in modern birds with one or two foveae compared to birds deprived of this specialty. Interspecies comparisons enabled us to identify elements of a hitherto unknown developmental process set up by foveate birds for increasing neuron density in the upper layers of their optic tectum. The late progenitor cells that generate these neurons proliferate in a ventricular zone that can expand only radially. In this particular context, the number of cells in ontogenetic columns increases, thereby setting the conditions for higher cell densities in the upper layers once neurons did migrate. [Display omitted] • The advent of the fovea was a breakthrough innovation in bird evolution. • Foveal vision requires increased neuron densities in the optic tectum. • Neuron densities are different when the foveae are deep or shallow. • Ganglion cell densities are higher in the shallow foveae than in the deep ones. [ABSTRACT FROM AUTHOR]

The maintenance of stable visual perception across eye movements is hypothesized to be aided by extraretinal information (e.g., corollary discharge [CD]). Previous studies have focused on the benefits of this information for perception at the fovea. However, there is little information on the extent that CD benefits peripheral visual perception. Here we systematically examined the extent that CD supports the ability to perceive transsaccadic changes at the fovea compared to peripheral changes. Human subjects made saccades to targets positioned at different amplitudes (4° or 8°) and directions (rightward or upward). On each trial there was a reference point located either at (fovea) or 4° away (periphery) from the target. During the saccade the target and reference disappeared and, after a blank period, the reference reappeared at a shifted location. Subjects reported the perceived shift direction, and we determined the perceptual threshold for detection and estimate of the reference location. We also simulated the detection and location if subjects solely relied on the visual error of the shifted reference experienced after the saccade. The comparison of the reference location under these two conditions showed that overall the perceptual estimate was approximately 53% more accurate and 30% less variable than estimates based solely on visual information at the fovea. These values for peripheral shifts were consistently lower than that at the fovea: 34% more accurate and 9% less variable. Overall, the results suggest that CD information does support stable visual perception in the periphery, but is consistently less beneficial compared to the fovea.

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.

Diabetic macular edema (DME) is a condition of retinal swelling due to the accumulation of leaked plasma in the extracellular space in the retina, known as the macula. DME is a chronic progressive retinal disorder that likely results in permanent complete blindness. The early signs of DME are not discernible by merely suspecting the fundus picture with the naked eye. Therefore, a computer-assisted diagnostic system could aid ophthalmologists in screening, diagnosing, and treating DME. This study proposes an efficient and complete model for early diagnosis and staging of DME. To overcome the challenges in precise localization of fovea, blood vessel network extraction, and accurate lesion segmentation, improved image relative subtraction, Gabor wavelet filter, and novel advanced fuzzy c-means clustering algorithms are introduced, respectively. Finally, the Bayesian classifier using the Gaussian function with expectation maximization is used for DME grading. The accurate optic disc and fovea localization, exudates’ segmentation, and classification improved the overall system’s performance. The proposed model achieves an average accuracy of 96.17%, 98.60%, 97.85%, and 98.80% for optic disc detection, fovea localization, exudates segmentation, and DME classification, respectively. The performance of the proposed model compared to the competitive studies illustrates the superiority of the suggested methodology.

Background: RS3PE (remitting seronegative symmetrical synovitis with edema and pitting) is a rare entity of unknown etiology that has been related to genetic predisposition due to the presence of HLA-A2 in 50% of cases and less frequently HLA-B7. Its pathogenesis is unknown, but it has been related to growth factors, and some mediators (TNF, IL-6). It is common in elderly people and the course of this illness presents with acute symmetrical polyarthritis, accompanied by edema in hands and feet. The diagnosis requires a high index of suspicion and to differentiate it from other entities such as rheumatoid arthritis, complex regional pain syndrome, rheumatic polymyalgia, in addition to ruling out malignant neoplasms, since there are many reports of its association with both solid and hematological neoplasms, being of bad prognosis when there is association. When there is no association with cancer, it responds well to the use of low doses of steroids and its prognosis is usually favorable. Clinical case: 80-year-old woman with an acute onset with polyarthralgia, functional limitation associated with pitting edema in hands and feet. After approaching the patient and ruling out associated neoplasms, it was diagnosed RS3PE. It was managed with prednisone, observing a good response, with remission of the manifestations at 6 weeks and subsequent suspension of the steroid. Conclusions: RS3PE is a rare entity, and a high index of suspicion is required for the diagnosis. A complete approach is important to rule out cancer in patients affected with this syndrome. Prednisone continues to be the best therapeutic option. [ABSTRACT FROM AUTHOR]

We have used recent measurements of mammalian cone light responses and voltage-gated currents to calculate cone ATP utilization and compare it to that of rods. The largest expenditure of ATP results from ion transport, particularly from removal of Na+ entering outer segment light-dependent channels and inner segment hyperpolarization-activated cyclic nucleotide-gated channels, and from ATP-dependent pumping of Ca2+ entering voltage-gated channels at the synaptic terminal. Single cones expend nearly twice as much energy as single rods in darkness, largely because they make more synapses with second-order retinal cells and thus must extrude more Ca2+ In daylight, cone ATP utilization per cell remains high because cones never remain saturated and must continue to export Na+ and synaptic Ca2+ even in bright illumination. In mouse and human retina, rods greatly outnumber cones and consume more energy overall even in background light. In primates, however, the high density of cones in the fovea produces a pronounced peak of ATP utilization, which becomes particularly prominent in daylight and may make this part of the retina especially sensitive to changes in energy availability.

The development of single-cell RNA sequencing (scRNA-seq) has allowed high-resolution analysis of cell-type diversity and transcriptional networks controlling cell-fate specification. To identify the transcriptional networks governing human retinal development, we performed scRNA-seq analysis on 16 time points from developing retina as well as four early stages of retinal organoid differentiation. We identified evolutionarily conserved patterns of gene expression during retinal progenitor maturation and specification of all seven major retinal cell types. Furthermore, we identified gene-expression differences between developing macula and periphery and between distinct populations of horizontal cells. We also identified species-specific patterns of gene expression during human and mouse retinal development. Finally, we identified an unexpected role for ATOH7 expression in regulation of photoreceptor specification during late retinogenesis. These results provide a roadmap to future studies of human retinal development and may help guide the design of cell-based therapies for treating retinal dystrophies.

A 28-year-old young Caucasian female patient without a history of trauma or vascular disease presented with blurred vision and paracentral scotoma in her left eye. Fundus examination showed a small foveal hemorrhage in the superficial retinal layers. Initial visual acuity was 20/50 in the LE. After 2 weeks, visual acuity increased to 20/20, and hemorrhage was resolved in optical coherence tomography angiography (OCT-A) spontaneously. No vascular lesion was seen in any layer of the retina in OCT-A analysis. [ABSTRACT FROM AUTHOR]

The macula, as the central part of the retina, plays an important role in the reading process. However, its morphology has not been previously studied in the context of dyslexia. In this research, we compared the thickness of the fovea, parafovea and perifovea between dyslexic subjects and normal controls, in 11 retinal segmentations obtained by optical coherence tomography (OCT). With this aim, we considered the nine sectors of the Early Treatment Diabetic Retinopathy Study (ETDRS) grid and also summarized data from sectors into inner ring subfield (parafovea) and outer ring subfield (perifovea). The thickness in all the four parafoveal sectors was significantly thicker in the complete retina, inner retina and middle retina of both eyes in the dyslexic group, as well as other macular sectors (fovea and perifovea) in the inner nuclear layer (INL), inner plexiform layer (IPL), IPL + INL and outer plexiform layer + outer nuclear layer (OPL + ONL). Additionally, the inner ring subfield (parafovea), but not the outer ring subfield (perifovea), was thicker in the complete retina, inner retina, middle retina (INL + OPL + ONL), OPL + ONL, IPL + INL and INL in the dyslexic group for both eyes. In contrast, no differences were found between the groups in any of the sectors or subfields of the outer retina, retinal nerve fiber layer, ganglion cell layer or ganglion cell complex in any eye. Thus, we conclude from this exploratory research that the macular morphology differs between dyslexic and normal control subjects, as measured by OCT, especially in the parafovea at middle retinal segmentations. [ABSTRACT FROM AUTHOR]

We provide the first measures of foveal cone density as a function of axial length in living eyes and discuss the physical and visual implications of our findings. We used a new generation Adaptive Optics Scanning Laser Ophthalmoscope to image cones at and near the fovea in 28 eyes of 16 subjects. Cone density and other metrics were computed in units of visual angle and linear retinal units. The foveal cone mosaic in longer eyes is expanded at the fovea, but not in proportion to eye length. Despite retinal stretching (decrease in cones/mm2), myopes generally have a higher angular sampling density (increase in cones/deg2) in and around the fovea compared to emmetropes, offering the potential for better visual acuity. Reports of deficits in best-corrected foveal vision in myopes compared to emmetropes cannot be explained by increased spacing between photoreceptors caused by retinal stretching during myopic progression.

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.

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]

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.

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]

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