Retinal development and visual sensitivity of young Pacific sockeye salmon (Oncorhynchus nerka)

1996 ◽  
Vol 199 (4) ◽  
pp. 869-882 ◽  
Author(s):  
I N Flamarique ◽  
C W Hawryshyn
Keyword(s):  
Rainbow Trout ◽  
Sockeye Salmon ◽  
Cell Layer ◽  
Retinal Development ◽  
Pigment Epithelium ◽  
Outer Nuclear Layer ◽  
Retinal Pigment ◽  
Visual Sensitivity ◽  
Polarization Sensitivity ◽  
Visual Cell

The development of photoreceptor cell types and the visual sensitivity of young sockeye salmon were examined. In contrast to previous findings from rainbow trout, rod outer segments were observed in the embryo 1.5 weeks before hatching. At this stage, a full square mosaic with accessory corner cones was visible in the central retina. Post-hatching retinal development is similar to that of other fish species. During the first 11 months of development, the fibrous and interplexiform layers, the outer nuclear layer, the visual cell layer and the retinal pigment epithelium thicken. The ganglion cell layer and the inner nuclear layer regress. In addition, the mean diameter of the cones increases, with that of double cones increasing faster than that of either of the single cone types. As is the case for other salmonids, the density of accessory corner cones diminishes after smoltification (a developmental stage in salmonids). The retina of smolts exhibits a full square mosaic pattern in some peripheral areas and near the central embryonic fissure. However, unlike findings from rainbow trout, compound action potential recordings from the optic nerve of smolt sockeye reveal the presence of four cone mechanisms with sensitivity maxima at 380 (ultraviolet), 425 (short), 520 (middle) and 635 nm (long wavelength). There is also a rod mechanism with maximum sensitivity around 530 nm. Smolts also exhibit polarization sensitivity to 380 nm light under a white crepuscular background.

scholarly journals The Impact of Glycemic Control on Retinal Photoreceptor Layers and Retinal Pigment Epithelium in Patients With Type 2 Diabetes Without Diabetic Retinopathy: A Follow-Up Study

2021 ◽  
Vol 12 ◽  
Author(s):  
Fukashi Ishibashi ◽  
Aiko Kosaka ◽  
Mitra Tavakoli
Keyword(s):  
Type 2 Diabetes ◽  
Diabetic Retinopathy ◽  
Retinal Pigment Epithelium ◽  
Glycemic Control ◽  
Pigment Epithelium ◽  
Outer Nuclear Layer ◽  
Retinal Pigment ◽  
Glycemic Variability ◽  
Hba1c Levels

AimsTo establish the sequential changes by glycemic control in the mean thickness, volume and reflectance of the macular photoreceptor layers (MPRLs) and retinal pigment epithelium in patients with type 2 diabetes without diabetic retinopathy.MethodsThirty-one poorly controlled (HbA1c > 8.0%) patients with type 2 diabetes without diabetic retinopathy undergoing glycemic control and 39 control subjects with normal HbA1c levels (< 5.9%) underwent periodical full medical, neurological and ophthalmological examinations over 2 years. Glycemic variability was evaluated by standard deviation and coefficient of variation of monthly measured HbA1c levels and casual plasma glucose. 3D swept source-optical coherence tomography (OCT) and OCT-Explorer-generated enface thickness, volume and reflectance images for 9 subfields defined by Early Treatment Diabetic Retinopathy Study of 4 MPRLs {outer nuclear layer, ellipsoid zone, photoreceptor outer segment (PROS) and interdigitation zone} and retinal pigment epithelium were acquired every 3 months.ResultsGlycemic control sequentially restored the thickness and volume at 6, 4 and 5 subfields of outer nuclear layer, ellipsoid zone and PROS, respectively. The thickness and volume of outer nuclear layer were restored related to the decrease in HbA1c and casual plasma glucose levels, but not related to glycemic variability and neurological tests. The reflectance of MPRLs and retinal pigment epithelium in patients was marginally weaker than controls, and further decreased at 6 or 15 months during glycemic control. The reduction at 6 months coincided with high HbA1c levels.ConclusionGlycemic control sequentially restored the some MPRL thickness, especially of outer nuclear layer. In contrast, high glucose during glycemic control decreased reflectance and may lead to the development of diabetic retinopathy induced by glycemic control. The repeated OCT examinations can clarify the benefit and hazard of glycemic control to the diabetic retinopathy.

Comparative analysis of cell distribution in the pigment epithelium and the visual cell layer of chimaeric mice

Development ◽  
1976 ◽  
Vol 36 (2) ◽  
pp. 425-430
Author(s):  
S. Sanyal ◽  
G. H. Zeilmaker
Keyword(s):  
Comparative Analysis ◽  
Cell Layer ◽  
Pigment Epithelium ◽  
Spatial Relation ◽  
Visual Cell ◽  
Cell Distribution ◽  
Retinal Layers

In chimaeras of both rdrdCC↔ + + cc and rdrdcc↔ + + CC combinations two types of distribution were observed. In a majority of the chimaeras both retinal layers were chimaeric; whereas in a few cases the pigment epithelium was chimaeric but the visual cell layer was made of + + cells only. No spatial relation was observed in the distribution of the cells in the two layers. The two eyes of the individuals were nearly always identical with regard to occurrence of chimaerism in the two layers. The findings are discussed in the light of the possible site and mode of expression of the rd gene.

Impaired visual thresholds in hypopigmented animals

1991 ◽  
Vol 6 (6) ◽  
pp. 577-585 ◽  
Author(s):  
Grant W. Balkema ◽  
Ursula C. Dräger
Keyword(s):  
Pigment Epithelium ◽  
Retinal Pigment ◽  
Visual Sensitivity ◽  
The Body ◽  
Melanin Pigmentation ◽  
Similar Threshold ◽  
The Mean ◽  
Single Unit Recordings ◽  
The Difference ◽  
And Function

AbstractOcular hypopigmentation is associated with neurological defects in structure and function. This paper investigates the ab/Fute visual thresholds in dark-adapted hypopigmented animals compared to their normally pigmented controls. Here we asked (1) whether the threshold elevation found in hypopigmented animals is a general consequence of the reduction in melanin content; (2) if so, which melanin components in the eye are likely to influence visual thresholds; and (3) whether similar threshold defects can be detected in orders other than rodents. By single-unit recordings from the superior colliculus, we compared incremental thresholds of normal black mice of the C57BL/6J strain to hypopigmented mutants: beige (bg/bg), pale ear (ep/ep), and albino (c2J/c2J) mice, three mutants in which melanin pigment throughout the body is affected; and Steel (Sl/Sld) and dorninant-spotting/W-mice (W/Wν), two mutants with normal pigmentation in the retinal pigment epithelium (RPE) but without any melanin in the choroid or the rest of the body. We found that all mutants had elevated thresholds that varied with the reduction in melanin. The albinos were 25 times less sensitive than black mice, pale ear mice 20 times, beige mice 11 times, and Steel and W-mice 5 times. The mean thresholds of dark-adapted black mice were 0.008 cd/m2. Recordings from rabbits showed a similar impairment of visual sensitivity: incremental thresholds were elevated 40 times in New Zealand-White albino rabbits (0.0008 cd/m2) compared to Dutch-Belted pigmented controls (0.00002 cd/m2). Previously, it has been shown that hypopigmented rats have elevated dark-adapted thresholds compared to pigmented controls (Balkema, 1988); here we show that the difference between hypopigmented rats and pigmented controls is not caused by insufficient dark adaptation or excessive variability in the results from albino mutant compared to its control.Mutations that cause a reduction of ocular melanin pigmentation, regardless of the gene mutated or the mechanism underlying the hypopigmentation, are accompanied by an elevation in visual thresholds which is roughly proportional to the reduction in melanin. Melanin both in the RPE and choroid exert an effect on visual thresholds. Like the defects in optic nerve crossing and eye movements, the effect of melanin on visual thresholds is not restricted to rodents, but is seen in other orders. The threshold impairment in hypopigmented animals cannot be explained by impaired photoprotection, but it points to another physiological action of melanin.

Outer nuclear layer relevance in visual function correlated to quantitative enface OCT parameters in Stargardt disease

2021 ◽  
pp. 112067212199057
Author(s):  
Dario Pasquale Mucciolo ◽  
Myrta Lippera ◽  
Dario Giorgio ◽  
Andrea Sodi ◽  
Ilaria Passerini ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Pigment Epithelium ◽  
Outer Nuclear Layer ◽  
Retinal Pigment ◽  
Ophthalmological Examination ◽  
Stargardt Disease ◽  
Rpe Atrophy ◽  
The Mean ◽  
Fundus Photographs ◽  
Auto Fluorescence

Purpose: To evaluate the correlation between Best Corrected Visual Acuity (BCVA) and the following parameters in Stargardt Disease (STGD): Central Retinal Thickness (CR-T), Central Outer Nuclear Layer Thickness (C-ONL-T), Areas of macular Photoreceptor loss (PHRa), and Retinal Pigment Epithelium (RPE) loss (RPEa). Methods: A total of 64 eyes of 32 STGD patients were included in the study. All patients received a comprehensive ophthalmological examination, color fundus photographs, fundus auto-fluorescence imaging, and Optical Coherence Tomography (OCT). The CR-T and C-ONL-T were evaluated from standard SD-OCT scans. The PHRa and RPEa were calculated from enface OCT scans (sub RPE slab and photoreceptor slab). The collected OCT parameters were evaluated for possible association with BCVA. Results: The mean macular PHRa and RPEa was 16.16 ± 13.36 and 12.05 ± 12.57 mm2 respectively. The mean CR-T measured 120.78 ± 41.49 μm while the mean C-ONL-T was assessed at 4.60 ± 13.73 μm. BCVA showed the highest correlation with the C-ONL-T ( r = −0.72; p < 0.001) while there was no correlation with the CR-T ( r = −0.17; p = 1.00). Conclusions: Enface OCT permits a rapid and precise quantitative evaluation of the macular PHR and RPE atrophy area in STGD. Nonetheless, the OCT parameter that showed the highest correlation with visual acuity in STGD was the ONL thickness.

scholarly journals Expression and protein sequence analyses of zebrafish impg2a and impg2b, two proteoglycans of the interphotoreceptor matrix

2021 ◽  
Author(s):  
M.E. Castellini ◽  
G. Spagnolli ◽  
E. Biasini ◽  
S. Casarosa ◽  
A. Messina
Keyword(s):  
Protein Sequence ◽  
Sequence Similarity ◽  
Pigment Epithelium ◽  
Outer Nuclear Layer ◽  
Retinal Pigment ◽  
Macular Dystrophy ◽  
Significant Similarity ◽  
Inherited Retinal Dystrophies ◽  
Extracellular Compartment ◽  
Interphotoreceptor Matrix

AbstractPhotoreceptor outer segments projecting from the surface of the neural retina toward the retinal pigment epithelium (RPE) are surrounded by a carbohydrate-rich matrix, the interphotoreceptor matrix (IPM) [1,2]. This extracellular compartment is necessary for physiological retinal function. However, specific roles for molecules characterizing the IPM have not been clearly defined [3]. Recent studies have found the presence of nonsense mutations in the interphotoreceptor matrix proteoglycan 2 (IMPG2) gene in patients affected by autosomal recessive Retinitis Pigmentosa (arRP) [4,5] and autosomal dominant and recessive vitelliform macular dystrophy (VMD) [6,7]. The gene encodes for a proteoglycan synthesized by photoreceptors and secreted in the IPM. However, little is known about the function and structure of this protein. We used the teleost zebrafish (D.rerio) as a model to study IMPG2 expression both during development and in adulthood, as its retina is very similar in humans [8]. In zebrafish, there are two IMPG2 proteins, IMPG2a and IMPG2b. We generated a phylogenetic tree based on IMPG2 protein sequence similarity among different vertebrate species, showing a significant similarity despite the evolutionary distance between humans and teleosts. In fact, human IMPG2 and D.rerio IMPG2a and IMPG2b share conserved SEA and EGF-like domains. Homology models of these domains were obtained by using the iTasser server. Finally, expression analyses of impg2a and impg2b during development and in the adult fish showed expression of both mRNAs starting from 3 days post fertilization (dpf) in the outer nuclear layer of zebrafish retina that continues throughout adulthood. This data lays the groundwork for the generation of novel and most needed animal models for the study of IMPG2-related inherited retinal dystrophies.

scholarly journals Association between Visual Acuity and Retinal Layer Metrics in Diabetics with and without Macular Edema

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
LakshmiPriya Rangaraju ◽  
Xuejuan Jiang ◽  
J. Jason McAnany ◽  
Michael R. Tan ◽  
Justin Wanek ◽  
...  
Keyword(s):  
Visual Acuity ◽  
Macular Edema ◽  
Layer Thickness ◽  
Pigment Epithelium ◽  
Outer Nuclear Layer ◽  
Retinal Pigment ◽  
Plexiform Layer ◽  
Retinal Layer ◽  
Inner Plexiform Layer ◽  
Retinal Microvasculature

Purpose. Diabetes is known to cause alterations in retinal microvasculature and tissue that progressively lead to visual impairment. Optical coherence tomography (OCT) is useful for assessment of total retinal thickening due to diabetic macular edema (DME). In the current study, we determined associations between visual acuity (VA) and retinal layer thickness, reflectance, and interface disruption derived from enface OCT images in subjects with and without DME. Materials and Methods. Best corrected VA was measured and high-density OCT volume scans were acquired in 149 diabetic subjects. A previously established image segmentation method identified retinal layer interfaces and locations of visually indiscernible (disrupted) interfaces. Enface thickness maps and reflectance images of the nerve fiber layer (NFL), combined ganglion cell and inner plexiform layer (GCLIPL), inner nuclear layer (INL), outer plexiform layer (OPL), outer nuclear layer (ONL), photoreceptor outer segment layer (OSL), and retinal pigment epithelium (RPE) were generated in the central macular subfield. The associations among VA and retinal layer metrics were determined by multivariate linear regressions after adjusting for covariates (age, sex, race, HbA1c, diabetes type, and duration) and correcting for multiple comparisons. Results. In DME subjects, increased GCLIPL and OPL thickness and decreased OSL thickness were associated with reduced VA. Furthermore, increased NFL reflectance and decreased OSL reflectance were associated with reduced VA. Additionally, increased areas of INL and ONL interface disruptions were associated with reduced VA. In subjects without DME, increased INL thickness was associated with reduced VA, whereas in subjects without DME but with previous antivascular endothelium growth factor treatment, thickening of OPL was associated with reduced VA. Conclusions. Alterations in retinal layer thickness and reflectance metrics derived from enface OCT images were associated with reduced VA with and without presence of DME, suggestive of their potential for monitoring development, progression, and treatment of DME.

scholarly journals Analysis of retinal sublayer thicknesses and rates of change in ABCA4-associated Stargardt disease

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
S. Scott Whitmore ◽  
Christopher R. Fortenbach ◽  
Justine L. Cheng ◽  
Adam P. DeLuca ◽  
D. Brice Critser ◽  
...  
Keyword(s):  
Vision Loss ◽  
Pigment Epithelium ◽  
Outer Nuclear Layer ◽  
Retinal Pigment ◽  
Macular Dystrophy ◽  
Stargardt Disease ◽  
Fiber Layer ◽  
Thickness Change ◽  
Photoreceptor Outer Segments ◽  
Sublayer Thickness

Abstract Stargardt disease, the most common inherited macular dystrophy, is characterized by vision loss due to central retinal atrophy. Although clinical trials for Stargardt are currently underway, the disease is typically slowly progressive, and objective, imaging-based biomarkers are critically needed. In this retrospective, observational study, we characterize the thicknesses of individual retinal sublayers by macular optical coherence tomography (OCT) in a large cohort of patients with molecularly-confirmed, ABCA4-associated Stargardt disease (STGD1) relative to normal controls. Automated segmentation of retinal sublayers was performed with manual correction as needed, and thicknesses in various macular regions were compared using mixed effects models. Relative to controls (42 eyes, 40 patients), STGD1 patients (107 eyes, 63 patients) had slight thickening of the nerve fiber layer and retinal pigment epithelium-Bruch’s membrane, with thinning in other sublayers, especially the outer nuclear layer (ONL) (p < 0.0015). When comparing the rate of retinal sublayer thickness change over time (mean follow-up 3.9 years for STGD1, 2.5 years for controls), STGD1 retinas thinned faster than controls in the outer retina (ONL to photoreceptor outer segments). OCT-based retinal sublayer thickness measurements are feasible in STGD1 patients and may provide objective measures of disease progression or treatment response.

scholarly journals Acute Retinal Pigment Epitheliitis: Spectral Domain Optical Coherence Tomography, Fluorescein Angiography, and Autofluorescence Findings

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Tuğba Aydoğan ◽  
Esra Güney ◽  
Betül İlkay Sezgin Akçay ◽  
Tahir Kansu Bozkurt ◽  
Cihan Ünlü ◽  
...  
Keyword(s):  
Optical Coherence Tomography ◽  
Fluorescein Angiography ◽  
Pigment Epithelium ◽  
Outer Nuclear Layer ◽  
Fundus Autofluorescence ◽  
Retinal Pigment ◽  
Spectral Domain ◽  
Fundus Examination ◽  
Optical Coherence ◽  
Sd Oct

A 17-year-old presented with central and paracentral scotomas in his right eye for one week. There was no remarkable medical or ocular history. Blood analyses were within normal range. At presentation both eyes’ best-corrected visual acuities were 20/20. Slit-lamp examination result was normal. Fundus examination revealed yellow-white hypopigmented areas in the macula. Fluorescein angiography (FA) showed hypofluorescence surrounded by ring of hyperfluorescence. Fundus autofluorescence (FAF) was slightly increased. Spectral domain optical coherence tomography (SD-OCT) showed disruption of IS/OS junction with expansion of abnormal hyperreflectivity from retinal pigment epithelium to the outer nuclear layer (ONL). One month later fundus examination showed disappearance of the lesions. FA revealed transmission hyperfluorescence. FAF showed increased autofluorescence and pigment clumping. Hyperreflective band in SD-OCT disappeared. Loss of photoreceptor segment layers was observed in some of the macular lesions. The diagnosis of acute retinal pigment epitheliitis can be challenging after disappearance of fundus findings. FA, FAF, and SD-OCT are important tests for diagnosis after resolution of the disease.

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