Abstract
Abstract: :
Purpose:Retinitis pigmentosa is referred to genetically, clinically heterogeneous group of photoreceptors degeneration. Diagnostic charactheristics common to the major part of RP include a history of night blindness, visual field constricted,waxy pallor of the optic disc,posterior pole subcapsular opacities and macular cistoid oedema (CME). We analysed the distribution of autofluorescence in RP considering the first an element of damage progression in correlation with the beginning of CME. Methods: 15 patients(30 eyes),aged between 23 to 27, were studied after a complete ophthalmological examination for 1 year. An analisis of the evidence of autofluorescence was performed. All patients had no CME ophthalmologically evident and to FAG. The autofluorescence at the posterior pole, was studied, after pupillary dilatation, with scanning laser ophthalmoscope(HRA). An informed consent was obtained. To evaluate the topographic distribution of Autofluorescence throughout the posterior pole a rectangular box, 10x750 pixels, was used as the area of analysis, placed horizzontally, across the macular area. The intensity of fundus autofluorescence of each pixel within the rectangular box was plotted against its degree of eccentricity. Results:In 8 eyes we found macular autofluorescence following by the evidence of CME in 5 eyes after 6 months.After 10 months other 6 eyes with macular autofluorescence, developed macular oedema. In the others (16 eyes) we found CME without macular autofluorescence. Conclusions: Lipofuscin, responsible of the autofluorescence, derives in part from incomplete degradation of phagocytosed outer segments of photoreceptor and is composed of various biomolecules. Some of its constituents have recently been shown to possess toxic properties in vitro and may play a pathophysiological role in retinal disease. Other authors found that in RP absent autofluorescence corresponded well spatially with outer retinal atrophy, while abnormally high background autofluorescence was seen in the macular region. But in our study we found in some patients a chronological correlation between macular autofluorescence and CME.Autofluorescence may help to understand the significance of these metabolic alteration in the pathogenesis of retinal disorders. Probably the autofluorescence in the macular area, corresponding to the accumulation of lipofuscin,determines a lot of alterations that precede the evidence of CME and its evidence may be helpful to predict the beginning of CME. We can study the distribution of the autofluorescence at the posterior pole to better control RP patient that can develop CME
Keywords: retinal degenerations: hereditary • photoreceptors • retinal pigment epithelium