Assessment of Hypofluorescent Foci on Late-Phase Indocyanine Green Angiography in Central Serous Chorioretinopathy

Association of Fundus Autofluorescence Abnormalities and Pachydrusen in Central Serous Chorioretinopathy and Polypoidal Choroidal Vasculopathy

A specific form of drusen, known as pachydrusen, has been demonstrated to be associated with pachychoroid eye diseases, such as central serous chorioretinopathy (CSC) and polypoidal choroidal vasculopathy (PCV). These pachydrusen have been found in up to 50% of eyes with CSC and PCV and may affect the disease progression and treatment response. This study aims to investigate the association between pachydrusen and changes in fundus autofluorescence (FAF) in eyes with CSC and PCV. A total of 65 CSC patients and 32 PCV patients were evaluated. Pachydrusen were detected using both color fundus photography and spectral-domain optical coherence tomography. The relationships between pachydrusen and FAF changes were then investigated. The prevalence of pachydrusen in CSC and PCV eyes was 16.7% and 61.8%, respectively. The mean age of patients with pachydrusen was significantly older than those without pachydrusen (CSC: 56.3 vs. 45.0 years, p < 0.001; PCV: 68.8 vs. 59.5 years, p < 0.001). No significant difference was found in the mean subfoveal choroidal thickness between eyes with or without pachydrusen. Eyes with pachydrusen were significantly associated with more extensive FAF changes in both CSC and PCV (p < 0.001 and p = 0.037, respectively). The study demonstrated that pachydrusen are more prevalent in PCV than CSC. Increasing age and more extensive abnormalities in FAF are associated with the presence of pachydrusen, suggesting that dysfunction of retinal pigment epithelial cells is associated with pachydrusen.

Choriocapillaris Flow Imbalance in Fellow Eyes in Age-Related Macular Degeneration

Purpose

The purpose of this study was to identify early changes in choriocapillaris flow in patients with age-related macular degeneration (AMD) with no history of macular neovascularization (MNV).

Methods

Clinical records of fellow eyes of patients with unilateral neovascular AMD without fundus findings and control eyes of otherwise healthy individuals, except for mild cataract, diagnosed at St. Luke's International Hospital from April 2020 to March 2021, were retrospectively analyzed. Optical coherence tomography (OCT) angiography images of the choriocapillaris slab were binarized using the Phansalkar local thresholding methods to evaluate the choriocapillaris flow area (CCFA) and its coefficient of variation (CV).

Results

The data of 24 AMD fellow eyes (17 for men, 71.7 ± 1.9 years old) and 21 control eyes (11 for men, 69.1 ± 2.0 years old) were analyzed. The mean CCFA ratio was lower in the AMD fellow eyes (58.6 ± 1.2%) than in the control eyes (62.4 ± 1.3%, P = 0.032), and the mean CV of CCFA ratio was greater in the AMD fellow eyes (0.174 ± 0.007) than in the control eyes (0.154 ± 0.007, P = 0.032). Eyes with CCFA ratio <60% and CV of CCFA ratio ≥0.154 had a 4.371-fold higher risk of being AMD fellow eyes (95% confidence interval = 1.029–18.56, P = 0.046). Differences in CV of CCFA ratio between AMD fellow eyes and control eyes were particularly clear in eyes with thick choroids (mean CV of CCFA in control versus AMD fellow eyes with central choroidal thickness ≥220 µm: 0.144 ± 0.005 vs. 0.173 ± 0.007, P = 0.009**).

Conclusions

Neovascular AMD fellow eyes without MNV had reduced, heterogeneous, and imbalanced choriocapillaris flow, which may constitute early changes in neovascular AMD, although further studies are required.

Retinal Diseases Regulated by Hypoxia-Basic and Clinical Perspectives: A Comprehensive Review

In recent years, the number of patients with age-related macular degeneration (AMD) is increasing worldwide along with increased life expectancy. Currently, the standard treatment for wet-AMD is intravitreal injection of anti-vascular endothelial growth factor (VEGF) drugs. The upstream of VEGF is hypoxia-inducible factor (HIF), a master regulator of hypoxia-responsive genes responsive to acute and chronic hypoxia. HIF activation induces various pathological pro-angiogenic gene expressions including VEGF under retinal hypoxia, ultimately leading to the development of ocular ischemic neovascular diseases. In this regard, HIF is considered as a promising therapeutic target in ocular ischemic diseases. In clinical ophthalmology, abnormal hypofluorescent areas have been detected in the late-phase of indocyanine green angiography, which are thought to be lipid deposits at the level of Bruch’s membrane to choriocapillaris in vitreoretinal diseases. These deposits may interfere with the oxygen and nutrients that should be supplied to the retinal pigment epithelium, and that HIF/VEGF is highly suspected to be expressed in the hypoxic retinal pigment epithelium, leading to neovascularization. In this review, we comprehensively summarize pathophysiology of AMD-related ocular diseases with the HIF/VEGF pathway from basic and clinic researches with recent findings.