Abstract
Optical coherence tomography (OCT) studies indicate that the foveal pit becomes shallower and narrower with increasing myopia. Foveal parameters in fellow eyes have been reported for healthy children. The purpose of this study was to examine how foveal pit dimensions compare in the fellow eyes of adult subjects whose refractions ranged from emmetropia to high myopia. Methods: Measurements were obtained on both eyes of 25 young adults. Refractions ranged from plano to -10.00 D with an average of -3.70 D. The largest interocular difference in refraction was 1.50 D. Axial length was measured with a Zeiss IOL Master. Retinal thickness was measured with an Optovue RTVue spectral domain OCT, using a rotary pattern of twelve 6-mm long scans through the fovea. The following parameters for each scan orientation were computed: maximum thickness on either side of the foveal pit, minimum thickness, pit depth, pit width at the maximum thickness and pit width at half the pit depth. Results: The interocular difference in axial length was correlated with the interocular difference in refraction, with the longer eye being more myopic (p<0.001). All foveal dimensions were correlated in fellow eyes (p<0.001). The interocular difference in pit width at half depth correlated with the interocular difference in refraction (p=0.04), such that the pit was narrower in the more myopic eye. Interocular difference in pit depth was correlated with interocular difference in minimum thickness (p<0.001), such that the eye with the shallower pit depth had the thicker foveal minimum. Conclusions: Foveal pit dimensions were very similar in fellow eyes over a range of refractions. Pit width was narrower in the more myopic eye. Pit depth could differ between eyes because of differences in minimum or maximum thickness, but the results indicate that the eye with the shallower foveal pit had greater foveal minimum thickness.