Quantification of Geographic Atrophy Using Spectral Domain OCT in Age-Related Macular Degeneration

Area of Science:

• Ophthalmology
• Medical Imaging
• Retinal Diseases

Background:

• Geographic atrophy (GA) is a leading cause of vision loss.
• Accurate measurement of GA area and enlargement rate is crucial for monitoring disease progression and evaluating treatments.
• Current imaging modalities have limitations in precisely quantifying GA.

Purpose of the Study:

• To compare the measurements of geographic atrophy (GA) area and enlargement rate using spectral domain optical coherence tomography (SD-OCT) with those obtained from fundus autofluorescence (FAF), color fundus photography (CFP), and infrared reflectance (IR) imaging.
• To evaluate the utility of retinal layer morphology in SD-OCT for GA area assessment.

Main Methods:

• A retrospective, multicenter case series included 70 eyes from 48 participants with GA.
• Participants underwent SD-OCT, FAF, CFP, and IR imaging at baseline and 12 months.
• GA area was measured using SD-OCT with two criteria (cRORA and hypertransmission) and compared with measurements from FAF, CFP, and IR. A custom tool was used for SD-OCT measurements, mapping retinal layer loss with co-registered IR images.

Main Results:

• Mean GA baseline area and annual enlargement rates measured by SD-OCT (cRORA and hypertransmission criteria) were comparable to FAF, CFP, and IR.
• No statistically significant differences were found in baseline GA area or annual enlargement rate between SD-OCT and the other imaging modalities.
• Circularity index was identified as a risk factor for increased annual GA enlargement rate.

Conclusions:

• Measuring GA using retinal layer morphology via SD-OCT provides a novel method for area quantification.
• GA area measurements can vary depending on the criteria used but are comparable across different imaging modalities.
• SD-OCT offers a valuable tool for assessing GA, complementing existing imaging techniques.