SPECTRAL DOMAIN OPTICAL COHERENCE TOMOGRAPHY FINDINGS IN COATS DISEASE

Multimodal imaging diagnosis and analysis of prognostic factors in patients with adult-onset Coats disease

AIM

To describe the multimodal imaging features, treatment, and outcomes of patients diagnosed with adult-onset Coats disease.

METHODS

This retrospective study included patients first diagnosed with Coats disease at ≥18 years of age between September 2017 and September 2021. Some patients received anti-vascular endothelial growth factor (VEGF) therapy (conbercept, 0.5 mg) as the initial treatment, which was combined with laser photocoagulation as needed. All the patients underwent best corrected visual acuity (BCVA) and intraocular pressure examinations, fundus color photography, spontaneous fluorescence tests, fundus fluorescein angiography, optical coherence tomography (OCT), OCT angiography, and other examinations. BCVA alterations and multimodal image findings in the affected eyes following treatment were compared and the prognostic factors were analyzed.

RESULTS

The study included 15 patients who were aged 24-72 (57.33±12.61)y at presentation. Systemic hypertension was the most common associated systemic condition, occurring in 13 (86.7%) patients. Baseline BCVA ranged from 2.0 to 5.0 (4.0±1.1), which showed improvement following treatment (4.2±1.0). Multimodal imaging revealed retinal telangiectasis in 13 patients (86.7%), patchy hemorrhage in 5 patients (33.3%), and stage 2B disease (Shield's staging criteria) in 11 patients (73.3%). OCT revealed that the baseline central macular thickness (CMT) ranged from 129 to 964 µm (473.0±230.1 µm), with 13 patients (86.7%) exhibiting a baseline CMT exceeding 250 µm. Furthermore, 8 patients (53.3%) presented with an epiretinal membrane at baseline or during follow-up. Hyper-reflective scars were observed on OCT in five patients (33.3%) with poor visual prognosis. Vision deteriorated in one patient who did not receive treatment. Final vision was stable in three patients who received laser treatment, whereas improvement was observed in one of two patients who received anti-VEGF therapy alone. In addition, 8 of 9 patients (88.9%) who received laser treatment and conbercept exhibited stable or improved BCVA.

CONCLUSION

Multimodal imaging can help diagnose adult-onset Coats disease. Anti-VEGF treatment combined with laser therapy can be an option for improving or maintaining BCVA and resolving macular edema. The final visual outcome depends on macular involvement and the disease stage.

ABNORMALITIES IN THE RETINAL CAPILLARY PLEXUSES IN COATS DISEASE IN ADULTHOOD ON OPTICAL COHERENCE TOMOGRAPHY ANGIOGRAPHY

PURPOSE

To describe and quantify the abnormalities of the retinal capillary plexuses using optical coherence tomography angiography in Coats disease.

METHODS

Retrospective study. Eleven eyes of 11 patients with Coats disease (9 men and two women aged 32-80 years) compared with nine fellow eyes and 11 healthy control eyes. Horizontal bands of contiguous 3 × 3 mm optical coherence tomography angiograms of the superficial vascular plexus and deep capillary complex were acquired from the optic disk to 6 mm temporal to the fovea, through areas with telangiectasia visible on fluorescein angiography in 9 cases.

RESULTS

The vascular density was significantly decreased in both plexuses in eyes with Coats disease compared with normal and fellow eyes within the 6 mm temporal to the fovea (superficial vascular plexus: 21.5 vs. 29.4%, P = 0.00004 and vs. 30.3%, P = 0.00008; deep capillary complex, 16.5 vs. 23.9%, P = 0.00004 and vs. 24.7%, P = 0.00008, respectively). The fractal dimension was also significantly decreased in eyes with Coats disease (superficial vascular plexus: 1.796 vs. 1.848 P = 0.001 and vs. 1.833, P = 0.003; deep capillary complex: 1.762 vs. 1.853, P = 0.003 and vs. 1.838, P = 0.004, respectively).

CONCLUSION

Retinal plexuses' vascular density was decreased in Coats disease, including in areas with no visible telangiectasia.

Optical Coherence Tomography and Optical Coherence Tomography Angiography in Pediatric Retinal Diseases

Indirect ophthalmoscopy and handheld retinal imaging are the most common and traditional modalities for the evaluation and documentation of the pediatric fundus, especially for pre-verbal children. Optical coherence tomography (OCT) allows for in vivo visualization that resembles histology, and optical coherence tomography angiography (OCTA) allows for non-invasive depth-resolved imaging of the retinal vasculature. Both OCT and OCTA were extensively used and studied in adults, but not in children. The advent of prototype handheld OCT and OCTA have allowed for detailed imaging in younger infants and even neonates in the neonatal care intensive unit with retinopathy of prematurity (ROP). In this review, we discuss the use of OCTA and OCTA in various pediatric retinal diseases, including ROP, familial exudative vitreoretinopathy (FEVR), Coats disease and other less common diseases. For example, handheld portable OCT was shown to detect subclinical macular edema and incomplete foveal development in ROP, as well as subretinal exudation and fibrosis in Coats disease. Some challenges in the pediatric age group include the lack of a normative database and the difficulty in image registration for longitudinal comparison. We believe that technological improvements in the use of OCT and OCTA will improve our understanding and care of pediatric retina patients in the future.

Adult-onset Coats' disease

Coats disease is an idiopathic retinal vasculopathy characterized by telangiectasia and aneurysm of retinal vessels along with intra and subretinal exudation and fluid. While Coats disease is classically described in young male population, there is an adult variant of Coats disease presenting in adulthood. Adult onset Coats disease have a similar presentation but a slower progression, localised lipid deposition, both peripheral and juxta-macular involvement. In this review article, we have attempted to describe in detail the characteristic clinical features, pathogenesis, investigation modalities and treatment in adult-onset Coats disease.

Multilayer subwavelength gratings or sandwiches with periodic structure shape light reflection in the tapetum lucidum of taxonomically diverse vertebrate animals

Eye shine in the dark has attracted many researchers to the field of eye optics, but the initial studies of subwavelength arrangements in tapetum began only with the development of electronic microscopy at the end of the 20th century. As a result of a number of studies, it was shown that the reflective properties of the tapetum are due to their specialized cellular subwavelength microstructure (photonic crystals). These properties, together with the mutual orientation of the crystals, lead to a significant increase in reflection, which, in turn, enhances the sensitivity of the eye. In addition, research confirmed that optical mechanisms of reflection in the tapetum are very similar even for widely separated species. Due to progress in the field of nano-optics, researchers now have a better understanding of the main principles of this phenomenon. In this review, we summarize electron microscopic and functional studies of tapetal structures in the main vertebrate classes. This allows data on the microstructure of the tapetum to be used to improve our understanding of the visual system.

Optical coherence tomography imaging of the pediatric retina

Optical coherence tomography is an increasingly important part of the retinal specialist's and general ophthalmologist's toolkit for diagnosing and managing retinal disease. This review summarizes the unique considerations and available imaging systems with which pediatric ophthalmologists should be familiar when attempting optical coherence tomography in children. Normal developmental changes in foveal and extrafoveal structure and the need for an established pediatric normative database of retinal thicknesses are reviewed. Finally, applications of optical coherence tomography imaging to selected representative pediatric retinal diseases are introduced as examples of how optical coherence tomography in children is furthering the diagnosis and management of vision-threatening retinal diseases.

Comparison of Optical Coherence Tomography With Fundus Photographs, Fluorescein Angiography, and Histopathologic Analysis in Assessing Coats Disease

Importance

Coats disease is a rare pediatric vitreoretinopathy that can cause devastating visual and anatomic outcomes.

Objective

To compare optical coherence tomography (OCT) with fundus photographs, fluorescein angiography (FA), and histopathologic findings in Coats disease.

Design, Setting, and Participants

This retrospective cohort study was conducted in a single tertiary institution (Duke Eye Center) and identified 28 children with Coats disease through a review of medical records from December 2002 to January 2018. Four eyes were obtained from a biorepository for histopathologic analysis.

Main Outcomes and Measures

Macular OCT, fundus photographs, and FA results were reviewed and compared for morphological changes. These were compared with retinal histopathological findings.

Results

The mean (SD) age was 9.5 (5.5) years for the 28 children (and 29 eyes) with clinical imaging results, and 24 (86%) were boys. A comparison between imaging modalities revealed OCT features that were not visible in photographs or FA, including exudates in multiple retinal layers (23 [82.1%]), small pockets of subretinal fluid (4 [14.3%]), an outer retinal atrophy overlying fibrotic nodules (7 [25.0%]), and small preretinal hyperreflective OCT dots (25 [89.3%]). Next, a comparison with light micrographs introduced an association of OCT findings with possible pathological features, including hyperreflective linear structures on OCT that appeared consistent with cholesterol crystals, small hyperreflective dots with macrophages, outer retinal tubulations with rosettes, and analogous OCT histopathology features such as intraretinal vessels entering fibrotic nodules and retinal pigment epithelium excrescences under the subretinal fluid. An OCT analysis revealed intraretinal cystoid spaces in 19 eyes, but in 9 of 19 (47.4) this was not associated with cystoid macular leakage; rather, fluorescein leakage was observed from peripheral telangiectatic vessels. Additionally, exudates were intraretinal only (6 [21.4%]) or both intraretinal and subretinal (17 [60.7%]); none were subretinal only. In eyes with follow-up results, new fibrosis developed in 8 of 17 eyes (47.1%). Fibrosis developed in 5 of 5 eyes (100%) with baseline subretinal fluid vs 3 of 12 without (25%; 95% CI, 22%-92%) and in 7 of 9 eyes (77.8%) with subretinal exudates vs 1 of 8 (12.5%) without (95% CI, 16%-89%).

Conclusions and Relevance

Optical coherence tomography may show the transient and permanent effects of Coats disease on the retina. These results suggest that exudates and fluid in the macular subretinal space appear later in the disease and may result in fibrosis formation. Further studies are needed to confirm if early treatment could prevent vision-threatening macular fibrosis.

Factors Predictive of Subretinal Fluid Resolution in Coats Disease: Analysis of 177 Eyes in 177 Patients at a Single Center

PURPOSE

The aim of this study was to investigate factors predictive of subretinal fluid (SRF) resolution in Coats disease.

DESIGN

Retrospective cohort study.

METHODS

Institutional review board-approved review of patients diagnosed with Coats disease demonstrating SRF (stage 3-5) at a single center from November 1973 to July 2018 with comparison of eyes that had resolution of SRF to those in which SRF persisted.

RESULTS

There were 177 cases (154 males, 87%) of Coats disease diagnosed at a mean age of 8 years. After a mean follow-up of 62 months, SRF resolved in 110 (62%) and persisted in 67 (38%) eyes. Comparison (resolved SRF vs persistent SRF) revealed classification as stage 3A [63 (57%) vs 20 (29%)], stage 3B [47 (43%) vs 40 (60%)], or stage 4 [0 (0%) vs 7 (11%)] (P < 0.001). Eyes with resolved SRF presented with fewer clock hours of telangiectasia (mean: 5 vs 7 clock hours, P < 0.001), light bulb aneurysms (mean: 5 vs 7 clock hours, P < 0.001), exudation (mean: 7 vs 10 clock hours, P < 0.001), and extent of SRF (mean: 7 vs 10 clock hours, P < 0.001). Factors predictive of SRF resolution included absence of iris neovascularization on fluorescein angiography [odds ratio 0.05 (95% confidence interval 0.01-0.60), P = 0.02], and less elevated SRF by ultrasonography [odds ratio 0.84 (95% confidence interval 0.76-0.95), P = 0.004). For every 1-mm decrease in SRF, likelihood of SRF resolution increased by 16%.

CONCLUSIONS

Resolution of SRF was achieved in the majority of eyes (62%) with stage 3 to 5 Coats disease. Predictors of SRF resolution included lack of neovascularization on fluorescein angiography and less elevation of SRF by ultrasonography.