Progressive Retinal Thinning in Sickle Cell Retinopathy

Retinal Sublayer Analysis in Autoimmune Retinopathy and Identification of New Optical Coherence Tomography Phenotypes

PURPOSE

Autoimmune retinopathy (AIR) is a poorly characterized disease with a wide phenotypic spectrum, complicating investigations of its underlying pathophysiology. We sought to analyze optical coherence tomography (OCT) retinal thickness changes in AIR patients.

METHODS

A retrospective chart review from 2007 to 2017 was performed evaluating AIR patients at a single academic, tertiary referral center. OCT retinal sublayer analysis was performed, and paradoxical thickening phenotypes were reviewed.

RESULTS

Twenty-nine AIR patients with positive anti-retinal antibodies and OCT imaging were identified. Overall, AIR patients had thinner retinal sublayers compared to controls; however, 12 patients (41.4%) had paradoxical thickening of the outer plexiform layer (OPL). This revealed two distinct OCT phenotypes. No association was found between retinal sublayer thickness and specific antiretinal antibodies.

CONCLUSIONS

While the pathogenicity of antiretinal antibodies remains unclear, the OCT phenotypes observed underscore the potential for identifying clues in the underlying disease processes and clinical diagnosis.

LONGITUDINAL ANALYSIS OF MICROVASCULAR CHANGES IN SICKLE CELL DISEASE USING SWEPT-SOURCE OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

PURPOSE

To analyze the changes in macular vascular densities (VDs) and foveal avascular zone (FAZ) over a 6-year period using swept-source optical coherence tomography angiography in patients with sickle cell disease compared with unaffected control subjects.

METHODS

Thirty eyes of patients with sickle cell disease and 12 eyes of unaffected control subjects matched for age and ethnicity were examined at a 6-year interval using the same imaging protocol, including ultra-wide-field angiography, swept-source OCT, and 3 × 3-mm optical coherence tomography angiography. The macular VD and FAZ were measured on ImageJ software according to previously reported algorithms.

RESULTS

In sickle cell eyes, the mean FAZ significantly increased ( P < 0.01), and the VD decreased in the foveal (within a circle of 1.5 mm in diameter around the foveal center) and temporal areas in both the superficial and the deep capillary plexuses ( P < 0.01). The VD did not change over time in the parafoveal area (annulus between two circles of 1.5 and 3 mm in diameter) and in the superior, inferior, and nasal sectors. No worsening of peripheral retinopathy was observed in the cohort during the follow-up, except for one eye that developed sea-fan. In the control eyes, no microvascular change was observed over time in FAZ size and VD.

CONCLUSION

These longitudinal optical coherence tomography angiography findings in patients with sickle cell disease showed an enlargement of the FAZ and a decrease in VD in the temporal and perifoveal regions despite the absence of progression of peripheral retinopathy, suggesting a worsening of the macular nonperfusion over time in sickle cell disease.

Longitudinal Assessment of Macular Thickness and Microvascular Changes in Children with Sickle Cell Disease

PURPOSE

To longitudinally assess macular thickness and microvascular changes in children with sickle cell disease (SCD).

DESIGN

A retrospective consecutive series.

SUBJECTS

Children with SCD aged ≤ 18 years who had an ophthalmic examination at Boston Children's Hospital between January 1998 and August 2022.

METHODS

Qualitative and quantitative analyses of both OCT and OCT angiography (OCTA) images were performed.

MAIN OUTCOME MEASURES

Total retinal thickness measured on macular OCT, superficial capillary plexus and deep capillary plexus (DCP) vessel density (VD), and foveal avascular zone (FAZ) area measured on 6- × 6-mm OCTA scans.

RESULTS

International Classification of Diseases, 10th Revision, code search identified 303 pediatric SCD patients who underwent ophthalmic examination during the study period. OCT and OCTA images were acquired on 104 (17.2%) and 60 (9.9%) eyes at presentation and on 159 (26.2%) and 100 (16.5%) eyes at final visit, respectively. Overall, temporal retinal thinning was noted qualitatively in 35.6% of SCD patients at presentation and 39.6% at final visit. Of those patients with macular thinning, 94.6% and 90.5% had peripheral sickle cell retinopathy (SCR) at presentation and final visit. On quantitative OCT analysis, HbSS eyes had a lower retinal thickness in the fovea and temporal parafovea compared with HbSC (P < 0.05). Eyes with peripheral SCR had a larger FAZ at presentation compared with eyes without peripheral SCR (P = 0.004), a lower DCP VD at final visit in the inferior temporal macula (P = 0.03), and a higher DCP VD at final visit in the superior nasal macula (P = 0.01). Eighty eyes of 40 patients had OCT, and 34 eyes of 20 patients had both OCT and OCTA images acquired at both initial and final visits. At final visit, retinal thickness decreased at the fovea, inferior perifovea, and temporal perifovea compared with presentation (P < 0.05). In parallel, VD DCP in the superonasal quadrant increased at final visit (P = 0.03).

CONCLUSIONS

Macular retinal thinning was progressive and observed in eyes with and without peripheral SCR. Over time, there was a compensatory increase in DCP VD in the nasal macula on OCTA.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Retinal atrophy and markers of systemic and cerebrovascular severity in homozygous sickle cell disease

Introduction

While paramacular retinal atrophy (PRA) is known to be found in 48% of eyes of adults and 42% of eyes of children with homozygous SCD (SS-SCD), the aim of this study is to assess the association between PRA and red blood cell (RBC) deformability, hematological markers and brain imaging abnormalities in SS-SCD.

Methods

This study is a subset of DREAM2, a prospective observational study performed between August 2015 and August 2016. Children (5–17 years) with SS-SCD and no history of large vessel vasculopathy, were included. Ophthalmological characteristics including visual acuity, fundus examination, OCT of central and temporal retina (with several retinal thickness measurements) were explored in relation with RBC deformability (ektacytometry), hematological and biochemical (hemolysis parameters), and neurological (cerebral oxygenation estimated by Near Infrared Spectroscopy, brain magnetic resonance imaging) investigations.

Results

17 children (5 boys; mean age: 13 years) with complete ophthalmological investigations were included in the analysis; 8 exhibited PRA. RBC deformability was found to be significantly lower in children with PRA for measurements made at 1.69 Pa (0.16 a.u ± 0.02 vs 0.21 a.u ± 0.03, p = 0.02) and above, as well as cerebral oxygenation (59.25% ± 9.9 vs 71.53% ± 4.9, p = 0.02). A significant positive correlation was found between temporal retinal thickness and hemoglobin level (ρ = 0.65, p = 0.007), hematocrit (ρ = 0.53, p = 0.04) and RBC deformability at 3 Pa (ρ = 0.75, p = 0.005) and above.

Conclusions

These results suggest that PRA could be an early marker of systemic severity and cerebral oxygenation in SCD. Whether it could help predicting cerebral vasculopathy requires further investigations.

Artificial intelligence for improving sickle cell retinopathy diagnosis and management

Sickle cell retinopathy is often initially asymptomatic even in proliferative stages, but can progress to cause vision loss due to vitreous haemorrhages or tractional retinal detachments. Challenges with access and adherence to screening dilated fundus examinations, particularly in medically underserved areas where the burden of sickle cell disease is highest, highlight the need for novel approaches to screening for patients with vision-threatening sickle cell retinopathy. This article reviews the existing literature on and suggests future research directions for coupling artificial intelligence with multimodal retinal imaging to expand access to automated, accurate, imaging-based screening for sickle cell retinopathy. Given the variability in retinal specialist practice patterns with regards to monitoring and treatment of sickle cell retinopathy, we also discuss recent progress toward development of machine learning models that can quantitatively track disease progression over time. These artificial intelligence-based applications have great potential for informing evidence-based and resource-efficient clinical diagnosis and management of sickle cell retinopathy.

Longitudinal Assessment of Retinal Thinning in Adults With and Without Sickle Cell Retinopathy Using Spectral-Domain Optical Coherence Tomography

Importance

Determination of retinal thinning rates may help to identify patients who are at risk of progression of sickle cell retinopathy.

Objective

To assess the rates of macular thinning in adults with and without sickle cell retinopathy using spectral-domain optical coherence tomography (OCT) and to identify ocular and systemic risk factors associated with retinal thinning.

Design, Setting, and Participants

This longitudinal prospective case-control study enrolled adult participants from a university-based retina subspecialty clinic between February 11, 2009, and July 3, 2019. The study was designed in autumn 2008 and conducted from February 2, 2009, to July 3, 2020. Participants with sickle cell retinopathy (sickle cell group) were matched by age and race with participants without sickle cell retinopathy (control group). Participants received annual spectral-domain OCT and clinical examinations. Those with at least 1 year of follow-up by July 3, 2020, were included in the analysis. Data were analyzed from February 2, 2009, to July 3, 2020.

Main Outcomes and Measures

The primary outcome was comparison of spectral-domain OCT measurements from early-treatment diabetic retinopathy study subfield rates of retinal thinning between eyes with and without sickle cell retinopathy and between different sickle cell hemoglobin subtypes. The secondary outcome was identification of ocular and systemic risk factors associated with rates of retinal thinning.

Results

Among 370 adults (711 eyes) enrolled in the study, 310 participants (606 eyes) had sickle cell retinopathy, and 60 participants (105 eyes) did not. Of those, 175 of 310 participants (56.5%; 344 of 606 eyes [56.8%]; mean [SD] age, 37.8 [12.8] years; 126 women [72.0%]) in the sickle cell group and 31 of 60 participants (51.7%; 46 of 105 eyes [43.8%]; mean [SD] age, 59 [15.4] years; 22 women [71.0%]) in the control group had at least 1 year of clinical and spectral-domain OCT follow-up data from baseline. The mean (SD) follow-up was 53.7 (32.6) months for the sickle cell group and 54.6 (34.9) months for the control group. Rates of macular thinning in the sickle cell group were significantly higher than those in the control group for the inner nasal (difference, -1.18 μm per year; 95% CI, -1.71 to -0.65 μm per year), inner superior (difference, -1.03 μm per year; 95% CI, -1.78 to -0.29 μm per year), inner temporal (difference, -0.61 μm per year; 95% CI, -1.16 to -0.07 μm per year), and outer nasal (difference, -0.41 μm per year; 95% CI, -0.80 to -0.03 μm per year) quadrants. Patients with sickle cell hemoglobin SC and sickle cell hemoglobin β-thalassemia subtypes had higher rates of retinal thinning than those with the sickle cell hemoglobin SS subtype. Risk factors associated with greater rates of retinal thinning included participant age, stage of retinopathy, previous stroke, and presence of hypertension, acute chest syndrome, or diabetes. Hydroxyurea therapy was associated with decreased rates of retinal thinning and may be a protective factor.

Conclusions and Relevance

In this study, rates of retinal thinning were higher among participants with sickle cell retinopathy compared with those without sickle cell retinopathy, and thinning rates increased with participant age and stage of retinopathy. These findings suggest that identifying anatomic worsening of sickle cell maculopathy through spectral-domain OCT may be a useful parameter to evaluate the progression of sickle cell retinopathy.

Deep Learning Detection of Sea Fan Neovascularization From Ultra-Widefield Color Fundus Photographs of Patients With Sickle Cell Hemoglobinopathy

Importance

Adherence to screening for vision-threatening proliferative sickle cell retinopathy is limited among patients with sickle cell hemoglobinopathy despite guidelines recommending dilated fundus examinations beginning in childhood. An automated algorithm for detecting sea fan neovascularization from ultra-widefield color fundus photographs could expand access to rapid retinal evaluations to identify patients at risk of vision loss from proliferative sickle cell retinopathy.

Objective

To develop a deep learning system for detecting sea fan neovascularization from ultra-widefield color fundus photographs from patients with sickle cell hemoglobinopathy.

Design, Setting, and Participants

In a cross-sectional study conducted at a single-institution, tertiary academic referral center, deidentified, retrospectively collected, ultra-widefield color fundus photographs from 190 adults with sickle cell hemoglobinopathy were independently graded by 2 masked retinal specialists for presence or absence of sea fan neovascularization. A third masked retinal specialist regraded images with discordant or indeterminate grades. Consensus retinal specialist reference standard grades were used to train a convolutional neural network to classify images for presence or absence of sea fan neovascularization. Participants included nondiabetic adults with sickle cell hemoglobinopathy receiving care from a Wilmer Eye Institute retinal specialist; the patients had received no previous laser or surgical treatment for sickle cell retinopathy and underwent imaging with ultra-widefield color fundus photographs between January 1, 2012, and January 30, 2019.

Interventions

Deidentified ultra-widefield color fundus photographs were retrospectively collected.

Main Outcomes and Measures

Sensitivity, specificity, and area under the receiver operating characteristic curve of the convolutional neural network for sea fan detection.

Results

A total of 1182 images from 190 patients were included. Of the 190 patients, 101 were women (53.2%), and the mean (SD) age at baseline was 36.2 (12.3) years; 119 patients (62.6%) had hemoglobin SS disease and 46 (24.2%) had hemoglobin SC disease. One hundred seventy-nine patients (94.2%) were of Black or African descent. Images with sea fan neovascularization were obtained in 57 patients (30.0%). The convolutional neural network had an area under the curve of 0.988 (95% CI, 0.969-0.999), with sensitivity of 97.4% (95% CI, 86.5%-99.9%) and specificity of 97.0% (95% CI, 93.5%-98.9%) for detecting sea fan neovascularization from ultra-widefield color fundus photographs.

Conclusions and Relevance

This study reports an automated system with high sensitivity and specificity for detecting sea fan neovascularization from ultra-widefield color fundus photographs from patients with sickle cell hemoglobinopathy, with potential applications for improving screening for vision-threatening proliferative sickle cell retinopathy.

Retinal Thickness and Microvascular Changes in Children With Sickle Cell Disease Evaluated by Optical Coherence Tomography (OCT) and OCT Angiography

PURPOSE

To compare the severity of macular vascular changes in children with sickle cell disease (SCD) vs age- and race-matched controls.

DESIGN

Cross-sectional study.

METHODS

Children (<18 years old) with HbSS and HbS variant (HbSC and HbS thalassemia) genotypes, and their age- and race-matched controls, were recruited between January 2017 and December 2018. All subjects underwent optical coherence tomography angiography (OCTA) scans centered on the fovea and temporal macula. Retinal thickness, superficial capillary plexus (SCP) and deep capillary plexus (DCP) vessel density (VD), and foveal avascular zone (FAZ) size were measured and compared between HbSS and HbS variant vs controls.

RESULTS

Thirty-four HbSS, 34 HbS variant (Goldberg staging 0-3 for SCD eyes), and 24 control eyes (total 48 children, aged 5-17 years) were included. Total VD (3-mm ETDRS circle) was lower in HbS variant eyes than in controls for both the SCP (42.9% vs 47.7%, P = .02) and DCP (47.4% vs 52.6%, P = .01). In HbSS eyes, VD was lower in the DCP (47.7%, P = .008) but not in the SCP (45.5%, P = .5), compared to controls. A higher proportion of HbSS (n = 18, 55%) than HbS variant eyes (n = 9, 26%) had pathologic areas of retinal thinning associated with SCP and DCP flow loss (P = .03). However, retinal thickness measurements and FAZ size did not differ between either HbSS or HbS variant group vs controls.

CONCLUSIONS

Children with SCD have similar retinal thickness but less dense vasculature on OCTA compared to age and race-matched controls, suggesting that microvascular insult may precede structural thinning.