Optical Coherence Tomography Findings for Nanophthalmic Eyes

Purpose: To describe the optical coherence tomography (OCT) findings for nanophthalmic eyes. Methods: In this retrospective, single-center, observational case series, 15 patients (28 eyes) with axial lengths of ≤20.5 mm were included. Ultrasonography (A- and B-scans), keratometry, and OCT were performed. The main outcome measures were average foveal thickness, foveal center point thickness, total macular volume, and a new quantitative measure of foveal depression, relative foveal depression (RFD). Reference values for RFD were obtained by examining 57 healthy eyes with axial lengths of 21.5 mm to 27 mm. Results: The foveae of nanophthalmic eyes had diminished foveal depression due to thickened outer retinal layers. One patient with papillomacular folds was identified as having posterior microphthalmos. There was a good correlation between axial length on one hand and foveal thickness, foveal center point thickness, macula volume, and RFD on the other hand (r = −0.58, −0.61, −0.56, and −0.70 with P = 0.003, 0.001, 0.004, and 0.000, respectively). The average RFD for eyes with normal axial lengths was 0.43. Conclusions: OCT findings for nanophthalmic eyes with foveal underdevelopment are different from posterior microphthalmos and foveal hypoplasia seen in other disorders. The new measure RFD is a useful tool in ocular tomography.