Widefield OCT Imaging for Quantifying Inner Retinal Thickness in the Nonhuman Primate

Area of Science:

• Ophthalmology
• Retinal Imaging
• Nonhuman Primate Models

Background:

• Optical coherence tomography (OCT) is crucial for assessing retinal health.
• Standard OCT scans provide detailed but limited field views.
• Widefield imaging offers a broader perspective for retinal analysis.

Purpose of the Study:

• To evaluate the agreement and repeatability of inner retinal thickness measurements using widefield OCT imaging compared to standard OCT scans.
• To assess the utility of widefield imaging for monitoring retinal changes in nonhuman primate models.

Main Methods:

• OCT scans (20°x20° raster, 12° circular, 55x45° widefield) were performed on 30 healthy rhesus monkeys.
• Custom neural network algorithms segmented retinal layers.
• Bland-Altman analysis compared circumpapillary retinal nerve fiber layer (RNFL) and ganglion cell inner plexiform layer (GCIPL) thickness between widefield and standard scans.

Main Results:

• Widefield imaging showed good agreement with standard scans for average RNFL thickness (bias = -1.03 µm) and GCIPL thickness (bias = 1.0 µm).
• Repeatability for both RNFL and GCIPL measurements using standard analysis was under 5.2 µm.
• Limits of agreement for 1°x1° superpixels were -13.9 to 13.7 µm for RNFL and -2.5 to 2.5 µm for GCIPL.

Conclusions:

• Inner retinal thickness measurements from widefield OCT imaging demonstrate good repeatability.
• Widefield imaging provides comparable results to standard OCT scans for retinal thickness assessment.
• Widefield imaging holds potential for enhanced monitoring of retinal ganglion cell loss in experimental glaucoma models.