ASSOCIATION OF LATTICE DEGENERATION IN PATIENTS WITH CHRONIC SEROUS CHORIO-RETINOPATHY

Objective: To establish the association of lattice degeneration in patients with chronic serous chorio-retinopathy at tertiary care ophthalmology hospital. Study Design: Comparative cross-sectional study. Place and Duration of Study: Armed Forces Institute of Ophthalmology, Rawalpindi, from Sep 2019 to Dec 2020. Methodology: The sample population comprised of 80 subjects which included 40 cases of chronic serous chorio-retinopathy and 40 controls. Chronic serous chorio-retinopathy was diagnosed by consultant ophthalmologist on basis of fluorescein angiography and spectral-domain optical coherence tomography. Peripheral retinal examination was done among all the study participants to look for lattice degeneration. Pearson chi-square test was applied to look for the relationship of various factors with lattice degeneration including the presence of chronic serous chorio-retinopathy. Results: Two groups with equal number of subjects were included in the study. Mean age of the study participants was 49.14 ± 2.93 years. 60 (75.0%) participants were male while 20 (25%) were female. Fifty four (67.5%) had no lattice degeneration while 26 (32.5%) showed the presence of lattice degeneration on detailed ophthalmic examination. Chi-square test showed that having chronic serous chorio-retinopathy and use of steroids were statistically significantly associated with presence of lattice degeneration among the study participants. Conclusion: Chronic serous chorio-retinopathy emerged as a condition strongly associated with lattice degeneration of peripheral retina. Use of topical or systemic steroids also increased the chances of developing lattice degeneration in our study population.

Retinoic acid signaling mediates peripheral cone photoreceptor survival in a mouse model of retina degeneration

Retinitis Pigmentosa (RP) is a wide array of progressive, debilitating visual disorders caused by mutations in a diverse set of genes. In both human patients and mouse models of RP, rod photoreceptor dysfunction leads to loss of night vision, and is followed by secondary cone photoreceptor dysfunction and degeneration, leading to loss of daylight color vision. A strategy to prevent secondary cone death could provide a generalized RP therapy to preserve daylight color vision regardless of the underlying mutation. In mouse models of RP, cones in the far peripheral retina survive long-term, despite complete rod loss. The mechanism for such peripheral cone survival had not been explored. Here, we found that active retinoic acid (RA) signaling in peripheral Muller glia is both sufficient and necessary for the extended cone survival. RA depletion by conditional knockout of RA synthesis enzymes, or overexpression of an RA degradation enzyme, abrogated peripheral cone survival. Conversely, constitutive activation of RA signaling in the central retina promoted long-term cone survival. These results indicate that RA signaling mediates the prolonged peripheral cone survival in the rd1 mouse model of retinal degeneration, and provide a basis for a generic strategy for cone survival in the many diseases that lead to loss of cone-mediated vision.

Bilateral Adie’s Pupil following Laser Treatment of the Ischemic Peripheral Retina for Uveitis: A Case Report

Adie’s pupil is a neurological condition of unknown origin with unusual, asymmetric presentation known as anisocoria with the enlarged pupil failing to react to light. It is believed that this pupillary abnormality results from damage to the ciliary ganglion or postganglionic short ciliary nerves. Affected individuals (usually female) may be symptomatic with photophobia or difficulty reading in the diseased eye. Although most Adie’s pupil cases are idiopathic, previous studies have associated photocoagulation and uveitis with symptom onset. To the best of our knowledge, there have been no reports of specific means of preventing Adie’s pupil. We describe a patient who experienced varying severities of Adie’s pupil after separate laser treatments of the ischemic peripheral retina for uveitis. Fluorescein angiography revealed peripheral retinal nonperfusion in the bilateral eyes of a 37-year-old Japanese female who had been suffering from posterior uveitis. To avoid proliferative changes, 360° laser photocoagulation of the retinal nonperfusion region located in the far periphery was first delivered to the left eye over 2 sessions. Soon after treatment, the patient complained of acute photophobia and blurred vision in the treated eye. Ocular examination revealed left pupil dilation and poor light sensitivity, although the pupil was reactive to a close stimulus. The left pupil also displayed positive denervation sensitivity based on the dilute pilocarpine (0.125%) test. Adie’s pupil was diagnosed based on these observations. Three months later, similar, albeit milder, findings were observed in her right eye after 360° peripheral laser photocoagulation that was more conservatively performed over 4 sessions. Four months after the first treatment, her subjective visual function had improved, and the pupil diameter had decreased to a normal size in both eyes without additional treatment. We encountered a patient whose severity of Adie’s pupil was apparently reduced by more conservative laser photocoagulation of the ischemic peripheral retina.

MRI-based 3D retinal shape determination

ObjectiveTo establish a good method to determine the retinal shape from MRI using three-dimensional (3D) ellipsoids as well as evaluate its reproducibility.Methods and analysisThe left eyes of 31 volunteers were imaged using high-resolution ocular MRI. The 3D MR-images were segmented and ellipsoids were fitted to the resulting contours. The dependency of the resulting ellipsoid parameters on the evaluated fraction of the retinal contour was assessed by fitting ellipsoids to 41 different fractions. Furthermore, the reproducibility of the complete procedure was evaluated in four subjects. Finally, a comparison with conventional two-dimensional (2D) methods was made.ResultsThe mean distance between the fitted ellipsoids and the segmented retinal contour was 0.03±0.01 mm (mean±SD) for the central retina and 0.13±0.03 mm for the peripheral retina. For the central retina, the resulting ellipsoid radii were 12.9±0.9, 13.7±1.5 and 12.2±1.2 mm along the horizontal, vertical and central axes. For the peripheral retina, these radii decreased to 11.9±0.6, 11.6±0.4 and 10.4±0.7 mm, which was accompanied by a mean 1.8 mm posterior shift of the ellipsoid centre. The reproducibility of the ellipsoid fitting was 0.3±1.2 mm for the central retina and 0.0±0.1 mm for the peripheral retina. When 2D methods were used to fit the peripheral retina, the fitted radii differed a mean 0.1±0.1 mm from the 3D method.ConclusionAn accurate and reproducible determination of the 3D retinal shape based on MRI is provided together with 2D alternatives, enabling wider use of this method in the field of ophthalmology.

Cerebral Artery Stenosis in a Young Stroke Patient with Eales’ Disease

Eales’ disease is an idiopathic disorder induced by ischemic retinal vasculitis, usually affecting the peripheral retina. We encountered a young patient diagnosed as cerebral infarction with a history of Eales’ disease. The patient’s middle cerebral artery showed multifocal stenosis with contrast enhancement, suggesting vasculitis. These findings might give clues to a rare cause of cerebral artery stenosis.

Evans blue staining to detect deep blood vessels in peripheral retina for observing retinal pathology in early-stage diabetic rats

AIM: To observe and compare the statistical significance of superficial and deep vascular leakage in the pathological changes of the diabetic rats retina after the Evans blue (EB) perfusion, and utilize the modified whole-retina spreading method to make the slides while protecting the periphery of the retina. METHODS: The Sprague-Dawley (SD) rats were randomly divided into 6 groups. Each group named as the normal groups for 4, 8, and 12wk and the diabetic groups for 4, 8, and 12wk. The EB was injected into the cardiovascular system of the rats at the different time points. The retina of each group was obtained for observation. RESULTS: The superficial vascular leakage was found in all 6 groups. The size of leakage area of superficial retinal blood vessels was (0.54±0.23)%, (0.65±0.11)%, and (0.58±0.10)% in normal group. No notable leakage was found in the deep blood vessels [(0.03±0.04)%, (0.03±0.05)%, and (0.03±0.05)%]. The deep retinal vascular leakage was found in the peripheral retina of diabetic rats. The size of leakage area of superficial retinal blood vessels in diabetic group were (0.53±0.22)%, (0.69±0.16)%, and (0.52±0.11)%. The leakage areas of deep blood vessels were (0.54±0.50)%, (1.42±0.16)%, and (1.80±0.07)% at 4, 8, and 12wk, respectively. There was a statistically difference of the leakage area between the 8th week and the 4th week of diabetes group (P=0.003). The statistically significant difference between the diabetes and the control groups was noted at 4wk and 8wk (P<0.001). CONCLUSION: The main retinal pathological changes of early-stage diabetic rats are the vascular leakage of the periphery of deep retina. Diabetic rats modeled after 8wk have semi-quantitative statistical difference compared with the normal rats, thus early intervention treatment research can start at this time point.

Peripheral optical coherence tomography assisted by scleral depression in retinopathy of prematurity

Objective: To determine whether handheld widefield optical coherence tomography (OCT) can be used to document retinopathy of prematurity (ROP) stage while using scleral depression to improve peripheral views. Design: Prospective observational study. Participants: Consecutive neonates admitted to the neonatal intensive care unit (NICU) in a single academic medical center who also met criteria for ROP screening and consented for research imaging. Methods: Scleral depression was combined with widefield OCT using an investigational 400-kHz, 55-degree field of view handheld OCT during ROP screening from October 28, 2020 to March 03, 2021. Main Outcome Measures: Acquisition of en face and B-scan imaging of the peripheral retina to objectively assess early vitreoretinal pathology, including the demarcation between vascularized and anterior avascular retina, the presence of early ridge formation, and small neovascular tufts. Results: Various stages of ROP were detected using a rapid acquisition OCT system. In one neonate, serial OCT imaging over a five-week period demonstrated accumulation of neovascular tufts with progression to stage 3 ROP with extraretinal fibrovascular proliferation along the ridge. Videography of this technique is included in this report for instructional purposes. Conclusions: Serial examinations using widefield OCT and scleral depression may improve detection and documentation of ROP disease progression. Earlier detection of ROP-related proliferation may prevent vitreoretinal traction, retinal detachment, and blindness.

Clinical and genetic features of retinoschisis in 120 families with RS1 mutations

Background/aimsX-linked retinoschisis (XLRS), associated with RS1, is the most common type of X-linked retinopathy in children. This study aimed to identify clinical and genetic features of retinoschisis in 120 families with RS1 variants in China.MethodsRS1 variants were collected from our in-house exome data and were predicted by multiple-step bioinformatics analysis. Clinical data of 122 patients from 120 families with potential pathogenic RS1 variants were analysed and summarised, respectively.ResultTotally, 79 hemizygous variants (53 missense, 25 truncation and 1 indel), were detected. All except one (78/79, 98.7%), including 22 novels, were classified as potential pathogenic and detected exclusively in 120 families with retinoschisis. Clinical data demonstrated an average age of presentation at 5 years (1 month–41 years). Macular changes were classified as macular schisis (87.5%), macular atrophy (10.7%), normal (0.9%) and unclassified (0.9%). Patients with macular atrophy had older age but similar visual acuity compared with macular schisis. Peripheral retinal changes included flat retinoschisis (52.4%), bullous retinoschisis (BRS) (10.7%) and normal-like (36.9%) patients. Spontaneous regression was observed in two patients with BRS on follow-up examination. Visual acuity in the peripheral retinoschisis group was worse than that without peripheral retinoschisis.ConclusionAlmost all rare RS1 variants were potential pathogenic. All patients with RS1 pathogenic variants showed detectable characteristics in the macula and/or peripheral retina. Our data on RS1 variants and associated clinical phenotypes may be of value for clinical diagnosis and genetic test of retinoschisis.

Effect of Axial Length on Full-Field and Multifocal Electroretinogram

Background The Electroretinogram is a mass potential, which reflects the summed electrical activity of the retina. Full-field ERG measures the electrical signals from the whole retina in response to a light stimulus. The weakness of the full-field ERG is that it cannot provide topographical information regarding the functional integrity of the retina and cannot detect subtle functional defects. The response is dominated by the peripheral retina due to its predominance of retinal cells. Aim of the Work to investigate the effect of axial length on fullfield (ffERG)and multifocal ERG (mfERG). Subjects and Methods Forty-four eyes of 44 healthy subjects were included in this case series study which has been conducted at Ain shams university hospitals after the approval of the research ethical committee in the faculty of medicine, Ain Shams University between July 2018 and September 2019. Full ophthalmologic examination was performed for all participants, including visual acuity assessment (Best corrected visual acuity) using Snellen chart, calculation of spherical equivalent (SE), slit Lamp biomicroscopy examination with IOP measurement via Goldmann applanation tonometry (GAT), and fundus examination by indirect ophthalmoscope or via 90 D VOLK lens to assess macular area. Axial length measurement, ffERG & mf-ERG. Results; We found that in the absence of fundus changes, mfERG parameters showed decreased amplitudes with increase in axial length. The Six- Rings Response Densities showed negative correlation with AL while there is no significant correlation between Six- Rings Response Densities and SE. The Six- Rings P1 Amplitude showed negative correlation with AL while there is no significant correlation between P1 Amplitude and SE. The Six- Rings N1 Amplitude showed negative correlation with AL while there is no significant correlation between P1 Amplitude and SE. The four- quadrant Response Densities showed negative correlation with AL while there is no significant correlation between four- quadrant Response Densities and SE. The four- quadrant P1 Amplitude showed negative correlation with AL while there is no significant correlation between P1 Amplitude and SE. The four- quadrant N1 Amplitude showed negative correlation with AL while there is no significant correlation between P1 Amplitude and SE. There is no significant correlation between full-field clinical ERG parameters and both AL and SE. Conclusion In the absence of fundus changes, mfERG parameters showed decreased amplitudes with increase in axial length. For correct interpretation of ERG responses in clinical practice, we recommend consideration of axial length measurement when evaluating mfERG responses.

Optical Coherence Tomography Angiography Features of Macular Epiretinal Neovascularization In Eales’ Disease: A Case Rreport

Background: Eales disease primarily affects the peripheral retina. However, posterior involvement can be seen. Macular epiretinal neovascularization is not commonly seen in Eales disease. This report highlights the morphology and origin of macular epiretinal neovascularization (ERN) using multimodal retinal imaging, including optical coherence tomography angiography (OCTA). Results: A 35-year-old man with no history of systemic disorders presented with gradual decrease of vision in his left eye. Fundus examination of his right eye showed peripheral sclerosed blood vessels, neovascularization of the optic disc and elsewhere, and macular ERN. The view of the left fundus was limited by vitreous haemorrhage. Fluorescein angiography (FA), of the right eye showed widespread peripheral capillary nonperfusion and leakage of dye from the retinal neovascularization and macular ERN. Macular Spectral domain optical coherence tomography (SD-OCT) of the right eye showed an epiretinal membrane and the presence of epiretinal neovascular lesions extending above the internal limiting membrane towards the vitreous. Optical coherence tomography angiography (OCTA) showed multiple tiny blood vessels at the macula that arose from the superficial retinal capillary plexuses and extended toward the vitreous. The corresponding B-scan showed flow signal through these vessels and the signal extend above the internal limiting membrane. Systemic work-up was negative except for strongly positive tuberculin skin testing giving the classic diagnosis of Eales disease. Patient was started on empirical anti-tubercular therapy and oral corticosteroids. Scatter laser photocoagulation was applied to nonperfused retinal zones. Despite adequate scatter laser ablation, the ERN failed to regress fully. Conclusions: Macular ERN can be seen in cases of classic Eales disease. The origin of macular ERN in our case was shown to be from the superficial retinal capillary plexuses. We also noted the slower regression rate of macular ERN as compared to the major neovascularizations of the optic disc and peripheral retina. Further research is needed to establish the pathogenesis of ERN and its optimal management.