FA, as a special kind of congenital stationary night blindness (CSNB) [5], characterized by its distinct fundus, dark-adaptation curve and ERG responses. As to its pathogen, present studies have focused on the Genes. Mostly, mutations in the RDH5 gene [6] (11-cis retinol dehydrogenase) affected retinoid metabolism (11-cis retinol dehydrogenase) in the visual cycle, leading to FA features. However, other genes mutation had been reported, as the RLBP1 gene [7] (retinaldehyde binding protein 1) and RPE65 gene [8] (RPE-specific protein). 11-cis retinol dehydrogenase, produced in the smooth endoplasmic reticulum of the pigment epithelium cells, has revealed great importance in the visual cycle and the production and accumulation of lipofuscin in the pigment epithelium cells. [9] So, the impairment of pigment epithelium cells accounts for not only the lesion position, but also the dark blindness symptoms. Strictly, FA is not totally stationary. Resent reports had detected the dysfunction of cone cells and the disruption of Ellipsoid zone in OCT. [10,11] Nonetheless, the autosomal dominant inheritance was reported before. However, in this report the family refused to perform genetic test. [12]
The most confusing differential diagnosis of FA is retinitis punctata albescens. In 1910, Lauber [1] firstly named FA and differentiate it from retinitis punctata albescens. The latter one, though shows similar dark blindness symptoms and white dots, has narrowing visual field, Retinitis Pigmentosa signs (pigmentation with bone-cells like, thin retinal vessels, disc with yellow-wax like) in the fundus, no recoverable ERG responses, and progressive visual impairment in both dark and light. The main points of FA diagnosis and its differential diagnosis were mostly found out by analysis of specific ophthalmic features. The psychological characteristics of the disease shows a dark adaptation delay---abnormal ERG, and declined amplitudes of cone and rod ERG, which would back to normal after 30-40 minutes. [13] Significant decline, but after a long enough period of dark adaptation can be to return to normal. In this report, we have presented multiple ophthalmic examinations to show the figure of FA more in detail. Besides traditional examinations (visual field, ERG, dark-adaption test, fluorescence angiography and OCT), we further performed multicolor-OCT and angio-OCT. As the pathology of FA goes, there were little vascular change sign in the macular area. However, multicolor-OCT revealed abnormal layers of retina enface, representing the accumulation of lipofuscin in retinal pigment epithelium cells, which corresponded to the hyperreflective lesions on OCT. The white dots in the fundus varied with age and genotype. [14] With time, it may fade away in patients with FA or after uveitis. Further observations were not included in this report.