Choroidal vascularity index in eyes with central macular atrophy secondary to age-related macular degeneration and Stargardt disease

Clinical Characteristics and Progression of Geographic Atrophy in a Japanese Population

PURPOSE

To elucidate the clinical characteristics and progression rate of geographic atrophy (GA) associated with age-related macular degeneration (AMD) in a Japanese population.

DESIGN

Retrospective, multicenter, observational study.

PARTICIPANTS

A total of 173 eyes from 173 patients from 6 university hospitals in Japan were included. Of 173 study eyes, 101 eyes from 101 patients were included in the follow-up group. All patients were Japanese, aged ≥ 50 years and had definite GA associated with AMD in at least 1 eye.

METHODS

The GA area was measured semiautomatically using fundus autofluorescence (FAF) images. In the follow-up group followed for > 6 months with FAF images, the GA progression rate was calculated by 2 methods: mm2 per year and mm per year using the square-root transformation (SQRT) strategy. Simple and multiple linear regression analyses were used to identify the baseline factors associated with the GA progression rate.

MAIN OUTCOME MEASURES

Clinical characteristics of GA and the GA progression rate.

RESULTS

The mean age was 76.8 ± 8.8 years, and 109 (63.0%) were males. Sixty-two (35.8%) patients had bilateral GA. The mean GA area was 3.06 ± 4.00 mm2 (1.44 ± 1.00 mm [SQRT]). Thirty-eight eyes (22.0%) were classified as having pachychoroid GA. Drusen and reticular pseudodrusen were detected in 115 (66.5%) and 73 (42.2%) eyes, respectively. The mean subfoveal choroidal thickness was 194.7 ± 105.5 μm. In the follow-up group (follow-up period: 46.2 ± 28.9 months), the mean GA progression rate was 1.01 ± 1.09 mm2 per year (0.23 ± 0.18 mm/year [SQRT]). In the multivariable analysis, the baseline GA area (SQRT; P = 0.002) and the presence of reticular pseudodrusen (P < 0.001) were significantly associated with a greater GA progression rate (SQRT).

CONCLUSIONS

Certain clinical characteristics of GA in Asian populations may differ from those in White populations. Asian patients with GA showed male dominance and relatively thicker choroid than White patients. There was a group with GA without drusen but with features of pachychoroid. The GA progression rate in this Asian population was relatively lower than that in White populations. Large GA and reticular pseudodrusen were associated with a greater GA progression rate.

FINANCIAL DISCLOSURE(S)

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

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.

Vessel density and choroidal vascularity index in patients with Bietti crystalline dystrophy and retinitis pigmentosa

OBJECTIVE

To evaluate and compare the vessel density (VD) using swept-source optical coherence tomography angiography (OCT-A) and the choroidal vascularity index (CVI) using spectral-domain optical coherence tomography (SD-OCT) in patients with Bietti crystalline dystrophy (BCD) and retinitis pigmentosa (RP).

MATERIALS AND METHODS

A cross-sectional retrospective study was conducted on 26 eyes of 13 BCD patients, 26 eyes of 13 RP patients, and 26 eyes of 13 age- and gender-matched healthy individuals. BCD patients were further staged as having early, intermediate, and advanced disease. VD was assessed in five quadrants of the macula (superior, temporal, inferior, nasal, and center) using a modified ETDRS technique with OCT-A. SD-OCT scans were binarized using Niblack's autolocal threshold, and CVI was determined as the ratio of the luminal area to the total choroidal area.

RESULTS

A significant difference was found in VD in all quadrants of the superficial capillary plexus (SCP) and the deep capillary plexus (DCP) slabs among the three groups (p < 0.001). A statistically significant difference was noted in the mean VD of temporal and inferior quadrants of the SCP and between the BCD and RP groups (p = 0.005, p = 0.015, respectively). A statistically significant difference was observed in the mean VD of the temporal, inferior, and nasal quadrants between the BCD and RP groups on DCP slabs (p = 0.002, p = 0.003, p = 0.003, respectively). The mean central choroidal thickness was 214.65±87.10 μm in the BCD group, 351.69±67.94 μm in the RP group, and 320.92±59.26 μm in the control group (p < 0.001). We found that CVI was significantly higher in the control group than BCD group (p < 0.001), and it was significantly lower in the BCD group when compared to the RP group (p < 0.001).There was no difference in CVI between RP and control groups (p = 0.948). Furthermore, the CVI was significantly lower in the intermediate and advanced disease stages than the early disease stage in the subgroup analysis of BCD patients (p < 0.001, p < 0.001, respectively).

CONCLUSION

CVI is a novel investigative tool to monitor disease progression. The CVI value was lower in BCD and RP patients than in the healthy subjects, and lower CVI values seem to be related to the disease severity in BCD patients. VD was also significantly lower in BCD patients when compared to RP patients, and VD analysis may help clinicians better understand the disease pathophysiology.

Interplay between aging and other factors of the pathogenesis of age-related macular degeneration

Age-related macular degeneration (AMD) is a complex eye disease with the retina as the target tissue and aging as per definition the most serious risk factor. However, the retina contains over 60 kinds of cells that form different structures, including the neuroretina and retinal pigment epithelium (RPE) which can age at different rates. Other established or putative AMD risk factors can differentially affect the neuroretina and RPE and can differently interplay with aging of these structures. The occurrence of β-amyloid plaques and increased levels of cholesterol in AMD retinas suggest that AMD may be a syndrome of accelerated brain aging. Therefore, the question about the real meaning of age in AMD is justified. In this review we present and update information on how aging may interplay with some aspects of AMD pathogenesis, such as oxidative stress, amyloid beta formation, circadian rhythm, metabolic aging and cellular senescence. Also, we show how this interplay can be specific for photoreceptors, microglia cells and RPE cells as well as in Bruch's membrane and the choroid. Therefore, the process of aging may differentially affect different retinal structures. As an accurate quantification of biological aging is important for risk stratification and early intervention for age-related diseases, the determination how photoreceptors, microglial and RPE cells age in AMD may be helpful for a precise diagnosis and treatment of this largely untreatable disease.