Comparison of Methods for Estimating Retinal Shape: Peripheral Refraction vs. Optical Coherence Tomography.

Area of Science:

• Ophthalmology
• Biomedical Optics
• Retinal Imaging

Background:

• Retinal shape is a key factor in myopia, often indirectly assessed via peripheral refraction (PRX).
• Distortion-corrected optical coherence tomography (OCT) offers a direct method for retinal shape analysis.

Purpose of the Study:

• To compare retinal curvature measurements derived from OCT scans versus PRX.
• To evaluate the agreement between OCT and PRX in estimating retinal shape across different meridians and refractive profiles.

Main Methods:

• Bland-Altman analysis was used to compare retinal radii derived from OCT and PRX in 25 participants.
• Pearson correlation assessed the relationship between radial differences and axial length.

Main Results:

• Low correlation was observed between PRX- and OCT-based retinal radii (ICC < 0.21).
• PRX measurements yielded flatter retinal curvatures than OCT, with varying agreement across meridians (0° meridian: +0.89 mm, 90° meridian: +0.08 mm).
• A negative correlation between axial length and method agreement was noted, particularly in the 90° meridian (R = -0.38, p = 0.06).

Conclusions:

• PRX measurements may underestimate retinal radius with increasing myopia compared to OCT.
• OCT imaging provides a more direct and potentially more accurate assessment of retinal shape.
• Caution is advised when interpreting PRX-derived retinal shape data; OCT is recommended for future studies.