Relationship between morphological and vascular alterations in geographic atrophy using a multimodal imaging approach

Area of Science:

• Ophthalmology
• Retinal Imaging
• Age-Related Macular Degeneration (AMD)

Background:

• Geographic atrophy (GA) is a leading cause of vision loss in AMD.
• Understanding the morphological changes in the retinal pigment epithelium (RPE) and choriocapillaris (CC) is critical for assessing GA progression.
• Multimodal imaging offers a comprehensive approach to evaluating these retinal layers.

Purpose of the Study:

• To assess geographic atrophy (GA) using a multimodal imaging approach.
• To focus on alterations in the retinal pigment epithelium (RPE) and choriocapillaris (CC) layers.
• To analyze lesion demarcation and morphological changes in atrophic and transition zones.

Main Methods:

• Inclusion of 57 eyes from 34 patients with atrophic AMD.
• Prospective, observational, cross-sectional study design.
• Utilized wide-field polarization-sensitive optical coherence tomography (PS-OCT), optical coherence tomography angiography (OCT-A), and fundus autofluorescence (FAF) for multimodal imaging.

Main Results:

• 91% of eyes showed focal hypodense areas at the CC level in GA transition zones on OCT-A.
• Increased depolarizing material (e.g., melanin) observed on PS-OCT en face maps corresponded to OCT-A hypodensities.
• All eyes exhibited abnormal FAF patterns and distinct alterations in CC flow architecture, with reduced CC patterns extending beyond GA margins in all cases.

Conclusions:

• OCT-A revealed varying degrees of CC flow impairment within GA lesions and transition zones.
• RPE alterations and depolarizing material accumulation can lead to misinterpretation of OCT-A imaging.
• Observed changes appear partially independent of autofluorescence altering processes.