Comparing Parafoveal Cone Photoreceptor Mosaic Metrics in Younger and Older Age Groups Using an Adaptive Optics Retinal Camera

BACKGROUND AND OBJECTIVE: To analyze cone mosaic metrics on adaptive optics (AO) images as a function of retinal eccentricity in two different age groups using a commercial flood illumination AO device. PATIENTS AND METHODS: Fifty-three eyes of 28 healthy subjects divided into two age groups were imaged using an AO flood-illumination camera (rtx1; Imagine Eyes, Orsay, France). A 16° × 4° field was obtained horizontally. Cone-packing metrics were determined in five neighboring 50 µm × 50 µm regions. Both retinal (cones/mm 2 and µm) and visual (cones/degrees 2 and arcmin) units were computed. RESULTS: Results for cone mosaic metrics at 2°, 2.5°, 3°, 4°, and 5° eccentricity were compatible with previous AO scanning laser ophthalmoscopy and histology data. No significant difference was observed between the two age groups. CONCLUSIONS: The rtx1 camera enabled reproducible measurements of cone-packing metrics across the extrafoveal retina. These findings may contribute to the development of normative data and act as a reference for future research. [ Ophthalmic Surg Lasers Imaging Retina. 2017;48:45–50.]