In Vivo Retinal Pigment Epithelium Imaging using Transscleral Optical Imaging in Healthy Eyes

• Published in: Ophthalmology science (Online) Vol. 3; no. 1; p. 100234
• Main Authors: Kowalczuk, Laura, Dornier, Rémy, Kunzi, Mathieu, Iskandar, Antonio, Misutkova, Zuzana, Gryczka, Aurélia, Navarro, Aurélie, Jeunet, Fanny, Mantel, Irmela, Behar-Cohen, Francine, Laforest, Timothé, Moser, Christophe
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Inc 01.03.2023; Elsevier
• Subjects: Adaptive Optics Transscleral Flood Illumination; Healthy volunteers; High resolution retinal imaging; Life Sciences; Original; Retinal Pigment Epithelium; Healthy volunteers; D; AF; RPE; AL; CoV; IOP; PRL; FOV; AO; Adaptive Optics Transscleral Flood Illumination; Retinal Pigment Epithelium; SD; CCS; QC; BCVA; RE; TOPI; NIR; SLO; High resolution retinal imaging; CCS, center-to-center spacing; AF, autofluorescence; AO, adaptive optics; FOV, field of view; IOP, intraocular pressure; NIR, near-infrared; CoV, coefficient of variation; RPE, retinal pigment epithelium; TOPI, transscleral optical imaging; D, diopters; SLO, scanning laser ophthalmoscope; PRL, preferred retinal locus; BCVA, best-corrected visual acuity; AL, axial length; SD, standard deviation; RE, refractive error; QC, quality criterion
• ISSN: 2666-9145; 2666-9145
• DOI: 10.1016/j.xops.2022.100234

To image healthy retinal pigment epithelial (RPE) cells in vivo using Transscleral OPtical Imaging (TOPI) and to analyze statistics of RPE cell features as a function of age, axial length (AL), and eccentricity. Single-center, exploratory, prospective, and descriptive clinical study. Forty-nine eyes (AL: 24.03 ± 0.93 mm; range: 21.9–26.7 mm) from 29 participants aged 21 to 70 years (37.1 ± 13.3 years; 19 men, 10 women). Retinal images, including fundus photography and spectral-domain OCT, AL, and refractive error measurements were collected at baseline. For each eye, 6 high-resolution RPE images were acquired using TOPI at different locations, one of them being imaged 5 times to evaluate the repeatability of the method. Follow-up ophthalmic examination was repeated 1 to 3 weeks after TOPI to assess safety. Retinal pigment epithelial images were analyzed with a custom automated software to extract cell parameters. Statistical analysis of the selected high-contrast images included calculation of coefficient of variation (CoV) for each feature at each repetition and Spearman and Mann–Whitney tests to investigate the relationship between cell features and eye and subject characteristics. Retinal pigment epithelial cell features: density, area, center-to-center spacing, number of neighbors, circularity, elongation, solidity, and border distance CoV. Macular RPE cell features were extracted from TOPI images at an eccentricity of 1.6° to 16.3° from the fovea. For each feature, the mean CoV was < 4%. Spearman test showed correlation within RPE cell features. In the perifovea, the region in which images were selected for all participants, longer AL significantly correlated with decreased RPE cell density (R Spearman, Rs = −0.746; P < 0.0001) and increased cell area (Rs = 0.668; P < 0.0001), without morphologic changes. Aging was also significantly correlated with decreased RPE density (Rs = −0.391; P = 0.036) and increased cell area (Rs = 0.454; P = 0.013). Lower circular, less symmetric, more elongated, and larger cells were observed in those > 50 years. The TOPI technology imaged RPE cells in vivo with a repeatability of < 4% for the CoV and was used to analyze the influence of physiologic factors on RPE cell morphometry in the perifovea of healthy volunteers. Proprietary or commercial disclosure may be found after the references.