Integrating Machine Learning and Traditional Survival Analysis to Identify Key Predictors of Foveal Involvement in Geographic Atrophy.

Purpose: The purpose of this study was to investigate the incidence of foveal involvement in geographic atrophy (GA) secondary to age-related macular degeneration (AMD), using machine learning to assess the importance of risk factors. Methods: Retrospective, longitudinal cohort study. Patients diagnosed with foveal-sparing GA, having GA size ≥ 0.049 mm² and follow-up ≥ 6 months, were included. Baseline GA area, distance from the fovea, and perilesional patterns were measured using fundus autofluorescence. Optical coherence tomography assessed foveal involvement, structural biomarkers, and outer retinal layers thickness. Onset of foveal involvement was recorded. Foveal survival rates were estimated using Kaplan-Meier curves. Hazard ratios (HRs) were assessed with mixed model Cox regression. Variable Importance (VIMP) was ranked with Random Survival Forests (RSF), with higher scores indicating greater predictive significance. Results: One hundred sixty-seven eyes (115 patients, average age = 75.8 ± 9.47 years) with mean follow-up of 50 ± 29 months, were included in this study. Median foveal survival time was 45 months (95% confidence interval [CI] = 38-55). Incidences of foveal involvement were 26% at 24 months and 67% at 60 months. Risk factors were GA proximity to the fovea (HR = 0.97 per 10-µm increase, 95% CI = 0.96-0.98), worse baseline visual acuity (HR = 1.37 per 0.1 LogMAR increase, 95% CI = 1.21-1.53), and thinner outer nuclear layer (HR = 0.59 per 10-µm increase, 95% CI = 0.46-0.74). RSF analysis confirmed these as main predictors (VIMP = 16.7, P = 0.002; VIMP = 6.2, P = 0.003; and VIMP = 3.4, P = 0.01). Lesser baseline GA area (HR = 1.09 per 1-mm2 increase, 95% CI = 1.01-1.16) and presence of a double layer sign (HR = 0.42, 95% CI = 0.20-0.88) were protective but less influential. Conclusions: This study identifies anatomic and functional factors impacting the risk of foveal involvement in GA. These findings may help identify at-risk patients, enabling tailored preventive strategies.

Optical coherence tomography biomarkers DROL, PROS, SND, hyperreflective walls of foveal cystoid spaces as predictors of central macular thickness and visual acuity in diabetic macular edema treated with intravitreal ranibizumab.

PURPOSE: This study aims to establish DROL (disruption of retinal outer layers), PROS (photoreceptor outer segment length), SND (subfoveal neuroretinal detachment), and hyperreflective walls of foveal cystoid spaces (HRW) as optical coherence tomography (OCT) biomarkers and predictors of central macular thickness (CMT) and visual acuity in diabetic macular edema (DME) treated with intravitreal ranibizumab (IVR). METHODS: In this prospective, interventional study performed at a tertiary care center over a span of 1 year from December 2021 to December 2022, 50 eyes of 46 patients of DME were included. Visual acuity and spectral domain OCT imaging were performed at baseline. Using inbuilt calipers on SD-OCT, the horizontal extent of DROL and the vertical extent of PROS were measured manually. SND and HRW were assessed qualitatively. IVR was administered and patients were followed up at 4, 8, and 12 weeks. RESULTS: The eyes without DROL had statistically significant (P < 0.05) lesser CMT and better BCVA (best-corrected visual acuity) (P < 0.05) after pro re nata injection of IVR. There was a positive correlation between the extent of baseline DROL with final CMT (P < 0.05) and final logMAR BCVA (P > 0.05), whereas negative correlation with the extent of baseline PROS with final CMT (P < 0.05) and final logMAR BCVA (P > 0.05). The presence of HRW and SND predicted non-resolution of CMT and worse visual acuity after treatment with IVR in DME. CONCLUSION: DROL, PROS, SND, and hyperreflective walls of foveal cystoid spaces may be utilized as qualitative as well as quantitative biomarkers to predict the post-treatment CMT and visual acuity in DME.

POSTOPERATIVE PHOTORECEPTOR INTEGRITY AND ANATOMICAL OUTCOMES BASED ON PRESENTING MORPHOLOGIC STAGE OF RHEGMATOGENOUS RETINAL DETACHMENT.

PURPOSE: To evaluate outer retinal recovery on postoperative optical coherence tomography (OCT) based on presenting morphologic stage of rhegmatogenous retinal detachment (RRD). METHODS: Retrospective cohort of consecutive primary fovea-involving RRDs, referred from January 2012 to September 2022. Baseline OCTs were assessed for morphologic stage of RRD. Postoperative OCT scans were graded at 3, 6, and 12 months for external limiting membrane, ellipsoid zone and interdigitation zone discontinuity, epiretinal membrane formation and severity, and residual subfoveal fluid. RESULTS: Three hundred and fifty-one patients were included. Increasing baseline morphologic stage of RRD was significantly associated with external limiting membrane, ellipsoid zone, and interdigitation zone discontinuity at all time points postoperatively ( P < 0.001) and was shown to be an independent predictor of foveal photoreceptor integrity after adjusting for height of detachment, time to surgery, and duration of fovea involvement ( P < 0.001). Earlier stages were associated with residual subfoveal fluid ( P < 0.001). There was no association between the stages of RRD and epiretinal membrane severity. However, late stages presented with earlier development of epiretinal membrane ( P = 0.012). CONCLUSION: Increasing morphologic stage of RRD is associated with delayed recovery of outer retinal bands in the first year and faster development of epiretinal membrane after RRD repair. The results of this study suggest that the stages may serve as a prognostic biomarker for postoperative photoreceptor recovery.

Foveal Microstructure and Visual Outcomes after Pars Plana Vitrectomy in Patients with Different Types of Epiretinal Membrane Foveoschisis.

INTRODUCTION: The aim of this study was to evaluate the clinical characteristics and surgical outcomes of the epiretinal membrane foveoschisis (ERM-FS) with different morphological types. METHODS: This retrospective observational study reviewed 44 consecutive ERM-FS patients who underwent ERM surgery. According to the optical coherence tomography images, ERM-FS was classified into three groups: group A, FS crossed the fovea with the foveola elevated; group B, FS located at the foveal edges with a near-normal central foveal point thickness; and group C, FS with undermined foveal edges with a near-normal central foveal point thickness. RESULTS: There were 10 eyes in group A, 20 eyes in group B, and 14 eyes in group C. Preoperatively, eyes in group A had the best best-corrected visual acuity (BCVA), the thickest central foveal point thickness, and the highest ellipsoid zone (EZ) intact rate among the three groups. After surgery, a resolution of foveoschisis was observed in 40.0%, 45.0%, and 50.0% of the eyes in group A, group B, and group C (p = 0.928), respectively. BCVA was significantly improved postoperatively. Although there was no significant difference in BCVA among the three groups at 1 month postoperatively, BCVA of group A was the best at 4 and 10 months. Correlation analysis indicated that the type of ERM-FS, baseline BCVA, central foveal point thickness, and postoperative EZ continuity (all p < 0.05) were important factors for the final BCVA. CONCLUSIONS: The damage to the retinal structure and visual function was milder in group A ERM-FS. Our study emphasized the necessity of OCT-based subtyping in patients with ERM-FS.

Genetic, morphological and electrophysiological findings in a patient with a rare pathogenic variant in the RS1 gene.

PURPOSE: In this study, we report a case of a young adult with X-linked juvenile retinoschisis (XLRS) with a rare pathogenic variant in the RS1 gene (c.522 + 2 T > A). METHODS: Ophthalmological evaluation, optical coherence tomography, full-field and multifocal electroretinograms and extensive genetic screening of genes related to visual loss were carried out in the participant. RESULTS: Clinical ophthalmological exams revealed a mild to moderate impairment of visual acuity. Retinal imaging showed bilateral foveal schisis, as well as normal a-wave, reduction in the b-wave amplitudes in dark- and light- adapted full-field electroretinograms, and abnormal oscillatory potentials. We found also diffuse amplitude reduction in multifocal electroretinogram arrays. A canonical splice variant was identified in the RS1 gene (c.522 + 2 T > A). CONCLUSION: A rare pathogenic variant of the RS1 gene was associated with diffuse retinal involvement (central and peripheral retina), probably in inner retina, and mild to moderate visual acuity impairment. The phenotypical characterization of rare mutations is relevant to provide information about the disease.

Foveal Pseudoduplication in a Young Male Patient.

This case report describes a diagnosis of pseudofovea found on examination in an otherwise asymptomatic young male patient.

Treatment Strategy With Gene Editing for Late-Onset Retinal Degeneration Caused by a Founder Variant in C1QTNF5.

Purpose: Genome editing is an emerging group of technologies with the potential to ameliorate dominant, monogenic human diseases such as late-onset retinal degeneration (L-ORD). The goal of this study was to identify disease stages and retinal locations optimal for evaluating the efficacy of a future genome editing trial. Methods: Twenty five L-ORD patients (age range, 33-77 years; median age, 59 years) harboring the founder variant S163R in C1QTNF5 were enrolled from three centers in the United Kingdom and United States. Patients were examined with widefield optical coherence tomography (OCT) and chromatic perimetry under dark-adapted and light-adapted conditions to derive phenomaps of retinal disease. Results were analyzed with a model of a shared natural history of a single delayed exponential across all subjects and all retinal locations. Results: Critical age for the initiation of photoreceptor loss ranged from 48 years at the temporal paramacular retina to 74 years at the inferior midperipheral retina. Subretinal deposits (sRET-Ds) became more prevalent as critical age was approached. Subretinal pigment epithelial deposits (sRPE-Ds) were detectable in the youngest patients showing no other structural or functional abnormalities at the retina. The sRPE-D thickness continuously increased, reaching 25 µm in the extrafoveal retina and 19 µm in the fovea at critical age. Loss of light sensitivity preceded shortening of outer segments and loss of photoreceptors by more than a decade. Conclusions: Retinal regions providing an ideal treatment window exist across all severity stages of L-ORD.

Photoreceptor Outer Segment Loss at the Macular Hole Border: Clinical Characteristics and Surgical Prognosis.

INTRODUCTION: During macular hole (MH) formation, the vitreofoveal traction may lead to foveal neural tissue avulsion and consequent photoreceptor loss. However, the clinical significance of the photoreceptor outer segment disruption at the MH border remains unclear. This study aims to investigate the clinical features and surgical outcomes of MHs with photoreceptor outer segment disruption at the MH border. METHODS: This study retrospectively reviewed 86 eyes from 85 patients who underwent vitrectomy combined with internal limiting membrane peeling for idiopathic MHs. Baseline and postoperative best-corrected visual acuity (BCVA) and foveal microstructure on optical coherence tomography images were compared between eyes with smooth and bumpy morphology, the latter of which was defined as those with an uneven and irregular surface with evident lumps and indentations at the MH border. RESULTS: The bumpy morphology was identified in 59 of 86 eyes (68.9%). At baseline, eyes with a bumpy MH morphology had a significantly larger minimum linear diameter (p = 0.043), a longer external limiting membrane defect (p = 0.013), and a worse baseline BCVA (p = 0.017) than those with a smooth morphology. Postoperatively, in a multivariate regression model adjusting preoperative confounding effects, eyes with bumpy borders were associated with a longer ellipsoid zone defect (p = 0.006) and a thinner central fovea (p = 0.002) at 1 month, and a thinner central fovea (p = 0.005) and a worse BCVA (p = 0.015) at 10 months. CONCLUSION: A severe photoreceptor outer segment loss is common at the MH border, which represents a chronic pathogenic process and may be an independent predictor for an incomplete photoreceptor recovery and worse long-term visual outcomes after surgery.

360-degree pedicled inverted internal limiting membrane flap technique without face-down posturing for large idiopathic macular holes: a retrospective case series.

PURPOSE: This study aimed to determine closure rates of large idiopathic macular holes treated with pars plana vitrectomy and 360-degree pedicled inverted internal limiting membrane flap without face-down posturing and define visual improvement, types of macular hole closure, and external retina integrity as secondary outcomes. METHODS: This retrospective case series analyzed all patients who were treated by vitrectomy, 360-degree pedicled inverted internal limiting membrane flap, and gas tamponade, without face-down posturing postoperatively. Age, sex, time of visual acuity reduction, other ocular pathologies, and lens status were collected. The best-corrected visual acuity and optical coherence tomography results were recorded during pre- and postoperative follow-up examinations (15 days and 2 months after surgery). RESULTS: This study enrolled 20 eyes of 19 patients, and the mean age was 66 years. Optical coherence tomography performed 2 months after surgery revealed hole closure in 19 (95%) eyes. The median best-corrected visual acuity improved from +1.08 preoperatively to +0.66 LogMAR 2 months postoperatively (p<0.001), with a median of 20 letters of visual improvement (0.4 LogMAR) on the Early Treatment Diabetic Retinopathy Study chart. V (47.36%)- and U (52.63%)-types of closure were observed. CONCLUSION: The 360-degree pedicled inverted internal limiting membrane flap technique, without face-down posturing, provided a high closure rate (95%), external layer recovery, and V- and U-type foveal closure contours, in addition to visual improvement in most cases of large macular holes (even macular holes >650 µm). This technique may be a viable alternative to patients in whom traditional postoperative face-down positioning for large macular hole treatment is not possible.

Concurrent Foveoschisis and Atrophy in a Patient With X-Linked Retinoschisis and Type 1 Diabetes Mellitus.

We report the case of a 28-year-old man with X-linked retinoschisis (XLRS) and type I diabetes mellitus. The patient had bilateral foveoschisis with a tractional retinal fold in the right eye. Optical coherence tomography (OCT) revealed hyperreflective material within the inner nuclear and outer plexiform layers, photoreceptor atrophy, and retinal pigment epithelium irregularities in both eyes. Fluorescein angiography showed hyperfluorescent foveal spots corresponding to the hyperreflective material observed on OCT. This is a unique presentation of XLRS, with concurrent foveoschisis and photoreceptor atrophy in both eyes. The hyperreflective material on OCT serves as a distinctive feature of XLRS. [Ophthalmic Surg Lasers Imaging Retina 2023;54:603-606.].

Effects of COVID-19 infection on retinal vascular density and choroidal thickness measured by optical coherence tomography angiography.

AIM: The present study evaluates the possible effects of COVID-19 on choroid thickness, the Foveal Avascular Zone (FAZ) and retinal vascular indices in the same individuals who had Optical Coherence Tomography (OCT) and Optical Coherence Tomography Angiography (OCTA) data prior to the COVID-19 pandemic. METHODS: The OCT and OCTA images of the same individuals with no known ophthalmic pathology who developed a COVID-19 infection were obtained were retrieved retrospectively from the database and compared with the repeated images of OCT and OCTA images 1-2 months after COVID-19 infection. RESULTS: Eighty eyes of 40 patients (26 female [65%], 14 male [35%]) who had developed a prior Covid-19 infection were included in the study. When comparing the measurements of the same participants before and after Covid-19 infection, no significant difference was detected in the mean average choroidal thicknesses (p=0.998), average superficial (p=0.425) and deep (p=0.333) retinal vascular densities, and superficial (p=0.991) and deep (p=0.075) FAZ measurements. CONCLUSIONS: No significant effect of COVID-19 on choroid thickness, FAZ or retinal vascular densities was noted in the present study, although there are some studies in literature with equivocal results.

Foveal photoreceptor disruption in ocular diseases: An optical coherence tomography-based differential diagnosis.

Fovea centralis, located at the center of the macula, is packed with cone photoreceptors and is responsible for central visual acuity. Isolated foveal photoreceptor disruption may occur in a variety of hereditary, degenerative, traumatic, and toxic chorioretinal diseases. These have been known previously by multiple synonyms including macular microhole, foveal spot, and outer foveal microdefects. A common clinical feature underlying these conditions is the presence of apparently normal fovea or subtle hypopigmented lesion at the foveal or juxtafoveal area. A detailed history along with high-resolution optical coherence tomography is often helpful to derive a conclusive diagnosis in majority of these cases. Focal photoreceptor disruption usually involves loss or rarefaction of ellipsoid/interdigitation zone, either in isolation or associated with external limiting membrane or retinal pigment epithelium disruption in the fovea. Vitreomacular interface (VMI) disorders including vitreomacular traction, posterior vitreous detachment, epiretinal membrane, and impending macular hole possibly remain the most common cause. Retinal dystrophies such as cone dystrophy, occult macular dystrophy, and achromatopsia may present with diminution of vision and normal appearing fundus in a younger age group. Other causes include photic retinopathy (e.g., from a history of sun gazing or laser pointer exposure), blunt trauma, drug exposure (e.g., poppers maculopathy or tamoxifen retinopathy), and acute retinal pigment epitheliopathy (ARPE). Visual prognosis depends on the underlying etiology with complete recovery common in the subset of patients with VMI, and ARPE, whereas persistent outer retinal defects are the rule in other conditions. We discuss the differential diagnoses that lead to isolated foveal photoreceptor defects. Identifying and understanding the underlying disease processes that cause foveal photoreceptor disruption may help predict visual prognosis.

Future perspectives for treating patients with geographic atrophy.

PURPOSE: Geographic atrophy (GA) is a late-stage form of age-related macular degeneration (AMD) characterized by the expansion of atrophic lesions in the outer retina. There are currently no approved pharmacological treatments to prevent or slow the progression of GA. This review describes the progression and assessment of GA, predictive imaging features, and complement-targeting investigational drugs for GA. METHODS: A literature search on GA was conducted. RESULTS: Expansion of atrophic lesions in patients with GA is associated with a decline in several measures of visual function. GA lesion size has been moderately associated with measures obtained through microperimetry, whereas GA lesion size in the 1-mm diameter area centered on the fovea has been associated with visual acuity. Optical coherence tomography (OCT) can provide 3-dimensional quantitative assessment of atrophy and is useful for identifying early atrophy in GA. Features that have been found to predict the development of GA include certain drusen characteristics and pigmentary abnormalities. Specific OCT features, including hyper-reflective foci and OCT-reflective drusen substructures, have been associated with AMD disease progression. Lesion characteristics, including focality, regularity of shape, location, and perilesional fundus autofluorescence patterns, have been identified as predictors of faster GA lesion growth. Certain investigational complement-targeting drugs have shown efficacy in slowing the progression of GA. CONCLUSION: GA is a progressive disease associated with irreversible vision loss. Therefore, the lack of treatment options presents a significant unmet need. OCT and drugs under investigation for GA are promising future tools for disease management.

Morphologic Stages of Rhegmatogenous Retinal Detachment Assessed Using Swept-Source OCT.

PURPOSE: To describe the sequential morphologic changes after rhegmatogenous retinal detachment (RRD) utilizing a novel, objective, and clinically relevant staging system based on swept-source OCT (SS-OCT) and determine its association with the duration of fovea-off and postoperative visual acuity (VA). DESIGN: Prospective cohort study. SUBJECTS: Consecutive patients with primary fovea-involving RRD referred to St. Michael's Hospital, Toronto, Canada, from January 2020 to April 2022. METHODS: All patients underwent SS-OCT and ultrawide-field SS-OCT at baseline. Primary RRDs with breaks above the 8- and 4-o'clock meridians were included. Patients with vision loss for ≥ 3 months, proliferative vitreoretinopathy grade C or worse, a demarcation line, previous vitrectomy, or other retinal pathology were excluded. The staging was based on an assessment of outer retinal morphology on successive SS-OCT scans from the peripheral break to the most posterior aspect of the RRD, following its direction of progression. MAIN OUTCOME MEASURES: Sequential outer retinal morphologic changes observed using SS-OCT and associated VA at 3 months after surgery. RESULTS: Forty-nine eyes were included. The mean age (standard deviation [SD]) was 61.2 (15.2) years. The mean presenting logarithm of the minimum angle of resolution (SD) acuity was 1.09 (0.75). All stages observed on a high-definition horizontal 51-line scan were reported. Outer retinal changes occurred in 5 stages: (1) separation of the neurosensory retina from the retinal pigment epithelium (42/49, 85.7%); (2) thickening of inner and outer segments of photoreceptors (45/49, 91.8%); (3) outer retinal corrugation formation: (3a) low-frequency (44/49, 93.6%) and (3b) high-frequency outer retinal corrugations (42/49, 85.7%); (4) loss of the definition of outer retinal corrugations, with concurrent thickening of inner and outer segments (26/49, 53.1%); and (5) patchy (moth-eaten) or complete loss of inner and outer segments (17/49, 34.7%). The mean duration of fovea-off by stage in the parafovea (SD) was 2 (1.4), 2.3 (1.2), 11.4 (8.1), and 12 (13.3) days for stages 3a, 3b, 4, and 5, respectively. There was a statistically significant association between increasing stage of RRD and longer duration of foveal involvement (P = 0.001) and, most importantly, between increasing stage and worse VA at 3 months after surgery (P = 0.011). CONCLUSIONS: This novel staging system describes the sequential morphologic changes in RRD using SS-OCT. Increasing stage of RRD was associated with worse VA at 3 months after surgery. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Retinal arcades in posterior microphthalmos: biometric correlation.

CLINICAL RELEVANCE: Posterior microphthalmos (PM) is a rare developmental disorder characterised by high hyperopia, short axial length, presence of retinal papillomacular fold and relatively normal anterior segment findings. BACKGROUND: The purpose of the study was to compare the retinal arcade distance from fovea between PM cases and to correlate axial shortening in PM eyes with imaging findings. METHODS: This retrospective, comparative case series included 24 eyes of 12 patients with PM as cases and an equal number of age- and sex-matched controls. Retinal findings on optical coherence tomography (OCT), OCT-angiography, Multicolour® image, axial length and corneal biometry were computed, compared and correlated between two groups. RESULTS: Retinal papillomacular fold was noted in all 24 PM eyes. Retinal arcade narrowing was noted in PM (p < 0.001). The central retina (p < 0.001) and choroid (p = 0.003) was thick in PM. Corneal biometry showed shorter axial length (p < 0.001), high keratometry readings (p < 0.001) and small corneal diameters (p = 0.011) in PM. Vessel density (p = 0.031) on OCTA was denser and foveal avascular zone area (p = 0.033) reduced in PM. Strong negative correlation of axial length with spherical equivalent (r = > -0.804;p < 0.001), vessel density (r = > -0.803; p = <0.001) and K1 (r = > -0.76; p < 0.001) and K2 (r = > -0.67; p = 0.001) keratometry readings was noted in PM. Significant positive correlation was noted between axial length and anterior chamber depth (r = 0.75; p < 0.001), foveal avascular zone area (r = 0.56; p = 0.033) and corneal diameter (r = 0.65; p = 0.001). Vessel density on OCT-angiography correlated positively with central corneal thickness (r = 0.552;p = 0.005) and corneal powers K1 (r = 0.709; p = 0.001) and K2 (r = 0.56; p = 0.004) and negatively with corneal diameter (r = > -0.521; p = 0.033). CONCLUSION: Increased choroidal thickening and retinal vascular arcade narrowing were two important, interesting observations noted with PM. Intercorrelation between the axial length, OCT, OCT-angiography and corneal biometry helped in understanding the pathogenesis and the structural and vascular changes in PM eyes.

Abnormal foveal morphology in carriers of oculocutaneous albinism.

BACKGROUND/AIMS: To investigate the foveal morphology in carriers of oculocutaneous albinism (OCA) using spectral domain optical coherence tomography (SD-OCT). A cross-sectional, observational study. METHODS: Handheld SD-OCT (Envisu C2300) was used to acquire horizontal scans through the centre of the fovea in biological parents of patients with OCA (n=28; mean age±SD=40.43±8.07 years) and age-matched and ethnicity-matched controls (n=28; mean age±SD=38.04±10.27 years). Sequence analysis was performed for variants in known genes associated with OCA. Best-corrected visual acuity (BCVA), presence of foveal hypoplasia and grade, foveal, parafoveal and perifoveal thickness measurements of total retinal layers (TRL), inner retinal layers (IRL) and outer retinal layers (ORL) thickness were measured. RESULTS: Foveal hypoplasia was identified in 32.14% of OCA carriers; grade 1 in all cases. OCA carriers demonstrated significant thicker TRL thickness (median difference: 13.46 µm, p=0.009) and IRL thickness (mean difference: 8.98 µm, p<0.001) at the central fovea compared with controls. BCVA of carriers was between -0.16 and 0.18 logMAR (mean: 0.0 logMAR). No significant differences in BCVA was noted between OCA carriers or controls (p=0.83). In the OCA carriers, we identified previously reported pathogenic variants in TYR, OCA2 and SLC45A2, novel OCA2 variants (n=3) and heterozygosity of the pathogenic TYR haplotype. CONCLUSION: We have, for the first time, identified foveal abnormalities in OCA carriers. This provides clinical value, particularly in cases where limited phenotype data are available. Our findings raise the possibility that previously reported mild cases of foveal hypoplasia or isolated foveal hypoplasia could correspond to OCA carrier status.

[The role of optical coherence tomography angiography in the assessment of retinal microcirculation in thrombotic microangiopathy associated with malignant arterial hypertension]. / Rol' opticheskoi kogerentnoi tomografii s funktsiei angiografii v otsenke retinal'noi mikrotsirkulyatsii pri tromboticheskoi mikroangiopatii, assotsiirovannoi so zlokachestvennoi arterial'noi gipertenziei.

Optical coherence tomography angiography (OCT-A) allows detailed assessment of the state of local blood flow in various systemic ischemic diseases, which include thrombotic microangiopathy (TMA) associated with malignant arterial hypertension (MAH). PURPOSE: To evaluate retinal microcirculation using OCT-A imaging data in the group of patients with TMA associated with MAH. MATERIAL AND METHODS: The study consisted of a qualitative and quantitative analysis of OCT-A data from 7 patients (14 eyes) with TMA associated with MAH and verified by renal biopsy. The control group included 7 healthy individuals (14 eyes). The following parameters were analyzed: area size of the foveal avascular zone FAZ, mm, vessel density (VD, %) and vessel skeleton density (VSD, %). The indicators were measured separately in the deep and superficial vascular plexuses and divided by localization into: the total density of the entire measured area, central density, density by quadrants (superior, inferior, nasal and temporal). All quadrants were subdivided into inner (corresponding to parafovea) and outer (corresponding to perifovea). RESULTS: Local foci of vascular attenuation of the deep retinal capillary plexus, pathological tortuosity of blood vessels in the deep and superficial retinal capillary plexuses were found in 100% of study group patients. Per-quadrant analysis of OCT-A finding in the macular zone revealed a statistically significant decrease in VD of the deep retinal capillary plexus (p<0.05). A direct correlation was found between glomerular filtration rate and the VD index in the outer inferior (r=0.567; p=0.034) and inner temporal quadrants (r=0.613; p=0.020) of the deep retinal capillary plexus, as well as the level of hemoglobin in blood serum and VD in inner temporal quadrant of the deep vascular plexus (r=0.596; p=0.025). CONCLUSION: Changes revealed with OCT-A are the symptoms of TMA in MAH patients spreading to the retinal microvasculature, mainly at the level of the deep retinal capillary plexus.

Evaluation of choroidal thickness with OCT in COVID-19 patients with high D-dimer levels.

To evaluate retinal and choroidal thickness with optical coherence tomography (OCT) to detect retinal and choroidal pathologies in coronavirus disease 2019 (COVID-19) patients with high D-dimer levels. Thirty patients who were hospitalized in the intensive care unit due to severe acute respiratory syndrome coronavirus 2 and whose D-dimer levels were high during this period, who applied to the internal medicine outpatient clinic between 15 and 30 days after discharge, and 30 healthy volunteers with similar age and gender as the control group was included in the study. After full ophthalmological examination, central foveal and choroidal thicknesses were evaluated using optical coherence tomography. Statistical analysis of the study data demonstrated that there was no significant difference between the groups in terms of age or gender (p > 0.05). There was also no statistically significant difference between the groups in terms of central foveal thickness, central choroidal thickness, or nasal 500, nasal 1500, temporal 500, or temporal 500 micron distances (p > 0.05 for all parameters). Choroidal and retinal vascular thicknesses were not affected in the short term in COVID-19 patients hospitalized in the intensive care unit.

Foveal Cone Structure in Patients With Blue Cone Monochromacy.

Purpose: Blue cone monochromacy (BCM) is a rare inherited cone disorder in which both long- (L-) and middle- (M-) wavelength sensitive cone classes are either impaired or nonfunctional. Assessing genotype-phenotype relationships in BCM can improve our understanding of retinal development in the absence of functional L- and M-cones. Here we examined foveal cone structure in patients with genetically-confirmed BCM, using adaptive optics scanning light ophthalmoscopy (AOSLO). Methods: Twenty-three male patients (aged 6-75 years) with genetically-confirmed BCM were recruited for high-resolution imaging. Eight patients had a deletion of the locus control region (LCR), and 15 had a missense mutation-Cys203Arg-affecting the first two genes in the opsin gene array. Foveal cone structure was assessed using confocal and non-confocal split-detection AOSLO across a 300 × 300 µm area, centered on the location of peak cell density. Results: Only one of eight patients with LCR deletions and 10 of 15 patients with Cys203Arg mutations had analyzable images. Mean total cone density for Cys203Arg patients was 16,664 ± 11,513 cones/mm2 (n = 10), which is, on average, around 40% of normal. Waveguiding cone density was 2073 ± 963 cones/mm2 (n = 9), which was consistent with published histological estimates of S-cone density in the normal eye. The one patient with an LCR deletion had a total cone density of 10,246 cones/mm2 and waveguiding density of 1535 cones/mm2. Conclusions: Our results show that BCM patients with LCR deletions and Cys203Arg mutations have a population of non-waveguiding photoreceptors, although the spectral identity and level of function remain unknown.