CHOROIDAL VASCULARITY INDEX IN HYDROXYCHLOROQUINE TOXIC RETINOPATHY: A Quantitative Comparative Analysis Using Enhanced Depth Imaging In Spectral Domain Optical Coherence Tomography.

PURPOSE: To investigate choroidal involvement in eyes of patients treated with hydroxychloroquine (HCQ), by quantifying the choroidal vascularity index (CVI) and other choroidal biomarkers. METHODS: Vertical enhanced depth imaging spectral domain optical coherence tomography (SD-OCT) scans were performed in eyes with either advanced-stage or mild HCQ toxic retinopathy, as well as in healthy age-matched and sex-matched controls. Based on SD-OCT scans, the subfoveal and mean choroidal thickness (ChT) was measured. The CVI, total choroidal area (TCA), luminal choroidal area (LCA), and stromal choroidal area (SCA) were calculated based on a binarization image process. These variables were computed and compared between the three groups (i.e., advanced stage, mild toxicity, and healthy controls). RESULTS: Forty-eight eyes of 47 patients under HCQ (26 eyes presented with advanced stage HCQ toxicity and 22 eyes with mild toxicity) and 34 eyes of 31 healthy controls were included. Both CVI and ChT were significantly different between the three groups ( P < 0.001, P < 0.001). When comparing the advanced stage toxicity group to healthy controls, both the subfoveal and the mean ChT were diminished ( P < 0.001). The CVI, TCA, LCA, and SCA were significantly lower in the advanced stage of toxicity group when compared with controls ( P < 0.001, <0.00001, <0.0001, and P = 0.0094, respectively). CONCLUSION: Our study suggests that eyes with HCQ toxic retinopathy, especially at advanced stages, present with choroidal impairment, giving further pathophysiological insights into the unfolding of this retinal toxicity.

Choriocapillaris Flow Deficits Quantification in Hydroxychloroquine Retinopathy Using Swept-Source Optical Coherence Tomography Angiography.

This study aims to quantitatively analyze choriocapillaris (CC) alterations using swept-source optical coherence tomography angiography (SS-OCTA) in eyes presenting with hydroxychloroquine (HCQ) toxic retinopathy and to compare it to patients under HCQ without toxic retinopathy and to healthy controls. For image analysis, CC en-face slabs were extracted from macular 6 × 6 mm SS-OCTA scans and a compensation method followed by the Phansalkar local thresholding was performed. Percentage of flow deficits (FD%) and other related biomarkers were computed for comparison. Fourteen eyes (7 patients) presenting with HCQ toxic retinopathy, sixty-two eyes (31 patients) under HCQ without signs of toxicity, and sixty eyes of 34 healthy controls were included. With regards to FD%, FD average size, and FD number there was a significant difference between the three groups (p < 0.05 with radius 4 and radius 8 pixels). Eyes presenting with HCQ toxicity had significantly higher FD% and average size, and a significantly lower number of FDs, with both radius 4 and 8 pixels. In conclusion, FD quantification demonstrates that CC involvement is present in HCQ toxic retinopathy, therefore giving pathophysiological insights with regards to the CC as being either the primary or secondary target of HCQ toxicity.

Quantitative Analysis of Choriocapillaris Using Swept-Source Optical Coherence Tomography Angiography in Eyes with Angioid Streaks.

Purpose: to quantitatively analyze choriocapillaris perfusion using swept-source optical coherence tomography angiography (SS-OCTA) in eyes presenting with angioid streaks in comparison with control eyes. Methods: Macular 6 × 6 mm SS-OCTA scans were retrospectively analyzed in eyes with angioid streaks and in control eyes. En face choriocapillaris flow images were compensated with en face choriocapillaris structure images, followed by the Phansalkar local thresholding method (with a window radius of four and eight pixels). Quantitative analysis was performed in the four peripheral 1 × 1 mm corners of the 6 × 6 mm SS-OCTA image to include equidistant and comparable regions. The percentage of flow deficits (FD%), the number and size of the flow deficits (FDs) and the total area of FDs were then calculated. Results: 54 eyes of 31 patients were included in the study: 27 eyes diagnosed with angioid streaks and 27 controls. Analysis of the four 1 × 1 mm peripheral corners of the 6 × 6 mm SS-OCTA image showed that eyes with angioid streaks had a higher FD% compared to the control group (47.62 ± 8.06 versus 38.90 ± 6.38 using a radius of four pixels (p < 0.001); 48.37 ± 7.65 versus 39.66 ± 6.51 using a radius of eight pixels (p < 0.001). The average size of FDs as well as the total area size of the FDs were significantly higher in eyes with angioid streaks compared to control eyes (p < 0.001). Eyes with angioid streaks present reduced choriocapillaris flow compared to control eyes. Decreased choriocapillaris perfusion may contribute, among other factors, to the development of neovascularization and atrophy in patients with angioid streaks.

OCT-angiography assessing quiescent and active choroidal neovascularization in retinitis pigmentosa associated with PRPH2 pathogenic variant.

PURPOSE: To report multimodal imaging findings including optical coherence tomography angiography (OCT-A) of a patient presenting with a quiescent choroidal neovascularization (CNV) in one eye and an active CNV in the fellow eye, complicating retinitis pigmentosa (RP) linked to PRPH2 pathogenic variant, with follow-up and management of both eyes. METHODS: Observational case report. RESULTS: A 40-year-old female with history of autosomal dominant RP consulted for acute visual loss in her right eye (RE). Multimodal imaging including OCT-A confirmed the diagnosis of active type 2 CNV in the RE and highlighted an incidental asymptomatic non-exudative "quiescent" CNV in the left eye (LE). This complication was managed by intra-vitreal Bevacizumab injections in the RE and regular monitoring of the LE. Frequent follow-up could detect early CNV activation signs in LE allowing early treatment. Mutation analysis of PRPH2 exons identified a known heterozygous pathogenic missense variation c.646C>T, p.P216S in exon 2. CONCLUSION: Multimodal imaging and especially OCT-A can be of a great help in the diagnosis and the management of CNV complicating RP, even at the stage of quiescent CNV. In presence of neovascular complication, PRPH2 gene should be investigated because of its frequent macular involvement despite high phenotypic variability.

E-learning for Ophthalmology Training Continuity During COVID-19 Pandemic: Satisfaction of residents of Hédi Raies Institut of Ophthalmology of Tunis.

INTRODUCTION: COVID-19 pandemic created great challenges for the continuity of medical education. At the Hédi Raies Institut of Ophthalmology of Tunis (HRIO), the need to ensure continuity in the teaching of ophthalmology has stimulated the development of a new e-learning resource based on clinical case studies. AIM:   To evaluate level of satisfaction of HRIO residents in regard to clinical case-study-based e-learning of ophthalmology. METHODS: Cross-sectional survey including 40 ophthalmology residents doing their internship at the ROHI during the first half of 2020. Learners were tutored in e-learning via the Moodle online learning platform and using a problem-solving format based on clinical case studies describing various ophthalmologic conditions. Data collection was carried out through an online survey after four months of training, designed to assess learners' satisfaction with the e-learning. RESULTS: Mean age of participants was 29.95 ± 1.73 years. The majority had found the navigation easy, the content relevant to their training objectives, and were satisfied with the discussion forums as a method of communication. All respondents were satisfied with clinical cases presented through the platform and felt that they helped them to better understand the content. Among them, 97.5% considered that this teaching method corresponded to their training needs. There was a statically significant difference in the level of knowledge before and after e-learning teaching, taking into account the residents' appreciation (p<0.001). CONCLUSIONS: This study highlights the importance of virtual learning in ophthalmology in the era of the COVID-19 pandemic. E-learning is well appreciated by ophthalmology residents, relatively easy to integrate to their training program, and reduces issues of time, patient availability and case exposure.