En Face Imaging of Geographic Atrophy Using Different Swept-Source OCT Scan Patterns.

Area of Science:

• Ophthalmology
• Medical Imaging
• Retinal Diseases

Background:

• Age-related macular degeneration (AMD) is a leading cause of vision loss.
• Geographic atrophy (GA) is an advanced form of nonexudative AMD.
• Accurate measurement of GA is crucial for monitoring disease progression and evaluating treatments.

Purpose of the Study:

• To compare the accuracy of different swept-source (SS) OCT scan patterns for measuring the area and enlargement of geographic atrophy (GA).
• To determine if SS OCT scan patterns provide similar measurements for GA in eyes with age-related macular degeneration (AMD).

Main Methods:

• A prospective, observational case series involving patients with GA secondary to nonexudative AMD.
• Patients underwent SS OCT imaging using both 6x6 mm and 12x12 mm scan patterns at baseline, 6 months, and 1 year.
• En face images were used to measure GA area, with slab boundaries set beneath Bruch's membrane.

Main Results:

• Mean baseline GA lesion areas were comparable between the 6x6 mm (3.81 mm²) and 12x12 mm (3.75 mm²) scans.
• Area measurements and annual enlargement rates (ERs) were similar between the two scan patterns over 1 year (P < 0.001).
• Annual ER measurements showed high correlation (Pearson r = 0.99) with an average ER of 0.3 mm/year.

Conclusions:

• Both 6x6 mm and 12x12 mm SS OCT scan patterns yield similar area and enlargement measurements for GA.
• The 12x12 mm scan pattern offers a wider field of view, enabling imaging of all macular GA.
• SS OCT imaging, particularly with the 12x12 mm FOV, can serve as a standalone tool for GA detection, measurement, and ER assessment in AMD clinical practice and trials.