Retinal pigment epithelium melanin imaging using polarization-sensitive optical coherence tomography for patients with retinitis pigmentosa

This study aimed to evaluate the distribution of retinal pigment epithelium (RPE) melanin in patients with retinitis pigmentosa (RP) using entropy measurements by custom-made polarization-sensitive optical coherence tomography (PS-OCT) images, and compare entropy with the intensity of short-wavelength (SW) and near-infrared (NIR) autofluorescence (AF). We retrospectively reviewed the retinal images, including PS-OCT, SW-AF, and NIR-AF of patients with RP who had a hyperautofluorescent ring on AF. A total of 12 eyes of 12 patients (8 women and 4 men; mean age: 37.9 years) were included. There was a strong positive correlation between entropy value and NIR-AF intensity (r = 0.626, p < 0.001), and there was a very weak negative correlation between entropy value and SW-AF (r = − 0.197, p = 0.001). The mean values of the entropy in the foveal, temporal (2 mm from the fovea), and nasal (2 mm from the fovea) sections were 0.41 (± 0.09), 0.29 (± 0.08), and 0.26 (± 0.08), respectively. The entropy was significantly higher in the foveal section than in the temporal and nasal sections (p = 0.002 and p = 0.003, respectively). There was no significant difference between the entropies values for the temporal and nasal sections ( p = 0.157). Age, logMAR best-corrected visual acuity, ellipsoid zone width, and central retinal thickness were not correlated with foveal entropy. We presented RPE melanin imaging in patients with RP using PS-OCT for the first time. PS-OCT can be a useful tool for monitoring patients with RP.