Abstract
Purpose: :
to investigate relationship between macular morphology and visual function in young patients with retinal dystrophy comparing high resolution, fourier domain optical coherence tomography (FD-OCT), fundus autofluorescence (FAF), fundus-related sensitivity (microperimetry), and correlate these with visual acuity (VA).
Methods: :
eleven retinal dystrophy patients underwent FD-OCT imaging using CirrusOCT (Carl Zeiss Meditec, Dublin, CA) and FAF of the macular area. All patients were also studied by means of microperimetry, which automatically analyses macular light differential threshold and fixation pattern. The thickness of retina (RT), inner retinal layer (IRL), and outer retinal layer (ORL) and photoreceptor (PR) layers were averaged over both 6-mm (macular) and 1.5-mm (foveal). Correlations were sought between central transverse photoreceptor loss, central foveal thickness, VA, FAF patterns and microperimetry.
Results: :
among the 22 eyes with retinal dystrophy (6 patients with cone-rode dystrophy, 1 with cone dystrophy, and 1 with bull’s eye maculopathy), OCT was capable of visualizing and quantifying regions with loss of the central photoreceptor layer in the foveal region. OCT scans revealed macular thinning and marked loss of the choriocapillaris. The retinal pigment epithelium was relatively more thinned centrally than peripherally. ORL OCT thickness profile shows marked thinning of the macular area ORL thickness. Patients without clinically evident central atrophy had small, focal parafoveal defects. A correlation was detected between VA and transverse PR loss (P=0.03). A statistically significant association of central foveal thickness with VA ( P=0.001) but not with transverse PR loss was observed. FAF showed a discrete arched line of increased autofluorescence surrounding an area with slightly decreased autofluorescence corresponding to the foveal area. Patients with abnormal FAF was significantly associated with poor VA and ultrastructural abnormalities as detected by FD-OCT (P=0001). Macular sensitivity was also significantly impaired over the foveal region and within the ring, and preserved outside the ring. A relative instability of fixation pattern characterized by predominantly eccentric fixation was observed.
Conclusions: :
The present study demonstrates the ultrastructural changes assessed with simultaneous FAF and FD-OCT and their relationship with visual outcome and microperimetry.
Keywords: macula/fovea • macular pigment • retinal degenerations: hereditary