Purpose
Different shapes of foveal depression have been described in otherwise normal eyes. It has been postulated that the shape of the foveal depression might result from the balance between centrifugal forces pushing the inner retina and centripetal forces that pulling the foveal cones towards its center. The Muller cell cone, which plays a structural support to the fovea, may also play a role in defining the shape of the foveal depression. “Flat-based” foveal depression is a unique shape that we observed in a small number of patients. The aim of this study was to assess if relations exist between this foveal shape and visual acuity (VA).
Methods
Retrospective chart review of seven patients with a flat-based foveal depression. Spectral domain optical coherence tomography was used to study the foveal depression shape and measure its parameters. Snellen chart was used to measure the VA.
Results
Seven eyes of 4 patients included; 3 cases were excluded due to incomplete data. All eyes had, on clinical examination, a darker fovea with a dull foveal reflex. In patient 1 (15 years) the eye exam and fluorescein angiography (FA) were normal. VA was 20/70 in the right eye and 20/20 in the left eye. Patient 2 (22 years), was suspected to have a retinal dystrophy because of macular retinal pigment epithelial changes. VA in right and left eye was 200/300 and 20/100 respectively. Patient 3, 60 years, had a full thickness macular hole in the right eye and a flat-based foveal depression in the left eye. VA in the left eye was 20/20, and the FA was normal. Patient 4, 38 years, fundus examination showed diffuse granular changes . VA in both eyes was 20/30, and the FA was normal. Foveal base width ranged from 525 um to 757 um. Central foveal thickness ranged from 163 um to 219 um. No intraretinal structural alterations around or within the fovea were noted.<br />
Conclusions
A Flat-based foveal depression is a peculiar and uncommon shape of foveal depression. It is often associated with a darker appearing fovea. No correlation with the visual acuity could be demonstrated. Larger scale studies are needed to better understand this peculiar shape of the fovea anatomically and functionally.