Initial Site of Macular Involvement in Central Retinal Dystrophies Revealed by Fundus Autofluorescence and Optical Coherence Tomography

Purpose: To determine the site of the initial alterations in the macula region in patients with central retinal dystrophies. Methods: Two hundred nine Japanese patients who were clinically or genetically diagnosed with central retinal dystrophies were retrospectively studied. The center of the small definitely decreased autofluorescence (DDAF) site in the fundus autofluorescence images that initially appeared in the macular region was defined as the site of the primary lesion of the retinal pigment epithelial (RPE) layer. The center of the ellipsoid zone (EZ) defect that initially appeared in the optical coherence tomographic images was defined as the site of the primary lesion of the photoreceptor layer. Results: The site of the primary lesion in the RPE layer was identified in 18 right eyes and 16 left eyes. The mean ± SD distance of these sites from the foveal center was 847.3 ± 233.4 µm in the right eye and 850.6 ± 144.3 µm in the left eye. The primary site of the lesion in the photoreceptor layer was identified in 16 of 342 eyes, and the mean ± SD distance from the foveal center was 847.4 ± 158.0 µm. 82.4% of the initial RPE lesion sites and 93.8% of the initial EZ lesion sites were located between 500 and 1,000 µm from the foveal center. We have named this region the parafoveal fragile zone (PFZ). Conclusions: The presence of a PFZ in eyes with central retinal dystrophies is most likely related to the unique anatomic and physiological characteristics of the macular region.