Choroidal thickness measurements in different ethnicities using swept source optical coherence tomography:...

Area of Science:

• Ophthalmology
• Medical Imaging
• Biomedical Engineering

Background:

• Investigating the repeatability of choroidal thickness measurements using swept-source optical coherence tomography (SS-OCT).
• Assessing the reliability of SS-OCT in young, healthy adults across different ethnicities.

Purpose of the Study:

• To evaluate the test-retest repeatability of choroidal thickness measurements obtained by SS-OCT.
• To determine if ethnic background, specifically pigmentation levels, influences measurement reliability.

Main Methods:

• Choroidal thickness was measured in 98 healthy South Asian and Caucasian subjects (ages 19-28) using SS-OCT.
• Repeated measurements were taken from the right eye, with analysis using interclass correlation coefficients and Bland-Altman methods.
• Automated segmentation algorithms were used for 9 subfields defined by the Early Treatment Diabetic Retinopathy Study.

Main Results:

• Mean sub-foveal choroidal thickness was 316.53 ± 63.36 µm (Caucasian) and 292.70 ± 60.13 µm (South Asian).
• Bland-Altman analysis revealed lower test-retest variability in Caucasians (-0.01 ± 6.59 µm) compared to South Asians (-2.38 ± 12.20 µm).
• No correlation was found between choroidal thickness and refractive error.

Conclusions:

• SS-OCT provides repeatable choroidal thickness measurements.
• Greater test-retest variability in South Asian subjects indicates potential impact of pigmentation on choroidal-scleral interface identification.
• Clinical relevance: SS-OCT may yield less reliable choroidal thickness data in highly pigmented individuals.