CORRELATION OF OUTER RETINAL TUBULATIONS AND CHORIOCAPILLARIS FLOW SIGNAL DEFICITS SURROUNDING GEOGRAPHIC ATROPHY

Area of Science:

• Ophthalmology
• Retinal Diseases
• Macular Degeneration

Background:

• Geographic atrophy (GA) is a leading cause of vision loss in age-related macular degeneration (AMD).
• Choriocapillaris vascular impairment is implicated in GA progression.
• Outer retinal tubulations (ORT) are a recently described finding in AMD.

Purpose of the Study:

• To compare paralesional and perilesional choriocapillaris vascular impairment in eyes with GA.
• To investigate differences in vascular impairment between GA with and without ORT.

Main Methods:

• Swept-source optical coherence tomography angiography (SS-OCTA) was used to image the choriocapillaris in 6x6 mm scans.
• En-face flow and structural images were analyzed for flow signal deficit (FD) in the paraatrophy and periatrophy zones.
• FD was quantified as the percentage of area affected by flow deficits (%FD).

Main Results:

• Twenty-four eyes with ORT and 18 eyes without ORT were analyzed.
• The paraatrophy zone exhibited greater %FD than the periatrophy zone in both groups.
• The difference in %FD between the para- and periatrophy zones (deltaFD) was significantly lower in eyes with ORT (1.85%) compared to eyes without ORT (4.00%).

Conclusions:

• Eyes with GA and ORT demonstrate less pronounced choriocapillaris impairment in the paraatrophy zone compared to the periatrophy zone.
• The paraatrophy zone consistently shows more significant flow deficits than the periatrophy zone in GA, irrespective of ORT presence.
• These findings suggest ORT may be associated with a different pattern or severity of underlying choriocapillaris vascular changes in GA.