Integrity of Foveal Cones in Early Age-related Macular Degeneration

In this article, we highlight a method that probes the directional sensitivity of cones, in particular those in the fovea. Directional sensitivity is a unique property of cones, i.e. it is not shared by any other retinal element, and can be taken as a measure of the health of cones. In a group of healthy subjects, the directional reflection was 1.78%. In early age-related macular degeneration (AMD), despite a healthy-looking fovea, the mean directional reflection was 0.92%; in late AMD, the figure decreased further to 0.86%. These findings point to a malfunctioning of the outer segments. In addition, the method yields an estimate of the optical density of macular pigment. In early AMD, the macular pigment did not differ from normal; this finding did not point to a protecting role of macular pigment in AMD.

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Drusen and pigment abnormality predict the development of neovascular age-related macular degeneration in Japanese patients

PLoS ONE ◽

10.1371/journal.pone.0255213 ◽

2021 ◽

Vol 16 (7) ◽

pp. e0255213

Author(s):

Shoji Notomi ◽

Satomi Shiose ◽

Keijiro Ishikawa ◽

Yosuke Fukuda ◽

Kumiko Kano ◽

...

Keyword(s):

Macular Degeneration ◽

Japanese Patients ◽

Age Related Macular Degeneration ◽

Neovascular Amd ◽

Fellow Eye ◽

Factors Associated ◽

Asian Populations ◽

Age Related ◽

The Mean

Drusen are known to be the important hallmark to predict the development of age-related macular degeneration (AMD). The prevalence of drusen is lower in Asians compared with Caucasians so that the role of signs constituting early AMD is not well established in Asian populations as in Western countries. In this study, we retrospectively investigated clinical characteristics and 5-year incidence of neovascular AMD (nAMD) in the fellow eye of unilateral nAMD patients. Of 296 consecutive unilateral nAMD patients who had been followed up more than 5 years, 170 typical AMD, 119 polypoidal choroidal vasculopathy, and 7 retinal angiomatous proliferation were included. To examine factors associated with nAMD occurrence in the fellow eye, drusen and pigmentary abnormality in the fellow eye were classified into 4 categories; Category 1: no or small drusen < 63 μm (37.2%), Category 2: 63–125 μm medium drusen or pigmentary abnormality (22.2%), Category 3: large drusen > 125 μm (25.0%), Category P: pachydrusen (15.5%). The mean sub-foveal choroidal thickness (SFCT) was Category 1: 276 μm, Category 2: 308 μm, Category 3: 246 μm, and Category P: 302 μm, respectively. Of note, SFCT in Category 2 and Category P was significantly larger than those of Category 3. Finally, the 5-year incidence of nAMD in the fellow eye was 32/296 (10.8%); Category 1: 0/110 (0%), Category 2: 12/66 (18.2%), Category 3: 20/74 (27.0%), and Category P: 0/46 (0%). Thus, signs of intermediate AMD (large drusen) as well as those of early AMD, especially the pigmentary abnormality, may contribute to development of bilateral nAMD in Japanese patients.

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