Utjecaj morfologije druza na sloj fotoreceptora u senilnoj makularnoj degeneraciji [Influence of drusen morphology on disruption of photoreceptor layer in age-related macular degeneration]

Abstract

INTRODUCTION: Age related macular degeneration (ARMD) is progressive neurodegenerative disease and one of the major causes of irreversible vision loss in developed countries. Dry form of ARMD is characterized with presence of abnormal pigment changes and drusen in macula which may lead to decrease in vision quality. Drusen are made of extracellular material situated between Bruch membrane and retinal pigment epithelium. With their position and growth they cause disturbance in their surroundings. OCT enables insight in drusen morphology as well in morphology of surrounding structures, first of all photoreceptors and retinal pigment epithelium. Although many papers that confirm presence of outer nuclear photoreceptor layer atrophy and atrophy of ellipsoid zone above drusen have been published, so far the relation between drusen morphology and photoreceptor atrophy has not been established. AIM OF STUDY: To determine which morphologic characteristics of drusen are related to photoreceptor atrophy as well to establish progression of photoreceptor atrophy in 2 years interval MATERALS AND METHOD: In this prospective study we analyzed and compared OCT scans of 44 eyes patients having dry drusiform ARMD in 2 years period. We used Optopol Copernicus 6x6 milimeter 3D scan of macular area. In every OCT scan we analyzed all drusen for their: number, shape, reflectivity, homogeneity, outer nuclear layer thickness, height, width, and central retinal thickness (CRT). RESULTS: Comparison of number of drusen related to photoreceptor atrophy on the beginning and the end of study revealed that there is statistically significant increase of drusen related to photoreceptor atrophy in 2 years period. On the other hand, decrease of drusen number not related to photoreceptor atrophy was noticed in the same period. Analysis of drusen height to ellipsoid zone and outer nuclear layer atrophy showed that the higher are the drusen the more significant atrophy above drusen exists. Analysis of drusen width to ellipsoid zone and outer nuclear layer atrophy showed that the wider are the drusen the more significant atrophy above drusen exists. Very interesting result occurred when we compared the eyes in which there was increase in number of drusen related to photoreceptor atrophy in to 2 years period to the eyes in which those kind of drusen were not present. The results showed, that eyes in which increase of drusen number related to photoreceptor atrophy was present, had statically higher values of CRT, average height and total drusen number. CONCLUSION: Interpretation of OCT scans in patients having drusiform ARMD should not be limited only to confirmation of dry form of disease or excluding wet form of disease. Every patient, after being diagnosed with certain disease is interested in their prognosis. Results of this study enable individual interpretation of drusen morphologic characteristics and provide more precise evaluation of stage and progression of disease for individual patient diagnosed with dry ARMD. With duration of dry ARMD there is increase of drusen number related to photoreceptor atrophy. The higher and wider in average the drusen are, the photoreceptor atrophy is more pronounced. Patients having higher total drusen number, higher average drusen height and higher CRT value have more chance for increase of drusen related to photoreceptor atrophy in period of 2 years and therefore probably more chance for vision deterioration