A Novel Strategy for Quantifying Choriocapillaris Flow Voids Using Swept-Source OCT Angiography

Area of Science:

• Ophthalmology
• Medical Imaging
• Biomedical Engineering

Background:

• The choriocapillaris is crucial for retinal health, but imaging it in vivo presents challenges.
• Flow voids within the choriocapillaris can indicate disease states.

Purpose of the Study:

• To develop reproducible swept-source OCT angiography (SS-OCTA) methods for imaging the choriocapillaris.
• To quantify associated flow voids and assess measurement repeatability.

Main Methods:

• SS-OCTA with a 3 × 3 mm scan pattern and complex optical microangiography (OMAG) algorithm.
• Defining the choriocapillaris slab and compensating for shadowing effects using structural information.
• Developing a thresholding method for flow void percentage calculation based on a normal database.

Main Results:

• SS-OCTA visualized the lobular capillary plexus of the choriocapillaris in normal subjects.
• Signal compensation reduced choriocapillaris flow voids and improved measurement repeatability.
• Optimal repeatability was achieved using a 1 standard deviation thresholding strategy.

Conclusions:

• SS-OCTA enables reproducible in vivo imaging of the choriocapillaris and its flow voids.
• High repeatability of flow void measurements was observed, even with drusen.
• This imaging capability can advance understanding of ocular disease onset, progression, and treatment response.