ABSTRACT
Objective: To investigate the clinicopathological correlation of parapapillary atrophy. Materials and Methods: The study included 16 eyes of rhesus monkeys (Macaca mulatta) – 4 eyes with experimental glaucoma, 11 eyes after experimental temporary occlusion of the central retinal artery, and 1 normal eye. On histological sections, we measured zones with different histological characteristics.On fundus photographs, alpha zone and beta zone of parapapillary atrophy were measured and correlated with the histological data. Results: The size of the clinical alpha zone of parapapillary atrophy was significantly correlated with the size of the histological region with irregularities of the retinal pigment epithelium (P = 0.05; correlation coefficient r = 0.49) and with the size of the histological region with a decreased density of retinal photoreceptors (P = 0.01; r = 0.60). The size of clinical beta zone of parapapillary atrophy significantly correlated with the size of the histological region with complete loss of the retinal pigment epithelium (P <0.001; r = 0.91), with the size of the histological zone with a complete loss of photoreceptors (P <0.001; r = 0.81), and with the size of the histological zone with a closed choriocapillaris (P <0.001; r = 0.89). Conclusions: The clinically seen alpha zone of parapapillary atrophy correlates with histological parapapillary irregularities of the retinal pigment epithelium and decreased density of retinal photoreceptors. The clinically seen beta zone of parapapillary atrophy correlates with histological complete loss of the retinal pigment epithelium and of the photoreceptors, and a closure of the choriocapillaris.
ABSTRACT
PURPOSE: To compare the confocal laser tomographic scanning evaluation with photographic measurements of the optic nerve head in a South Indian population. METHODS: The prospective comparative clinical non-interventional epidemiologic study included 62 subjects (62 eyes) forming a population-based sample, selected randomly. Mean age was 47.2 +/- 8.9 years, mean refractive error measured was -0.17 +/- 1.10 diopter (range, - 4.50 to + 2.50 diopter). Confocal laser scanning tomographic images on Heidelberg Retina Tomograph (HRT) and colour optic disc photographs were morphometrically analysed and compared. Main outcome measures were morphologic optic disc parameters. RESULTS: The optic disc area measurements were significantly smaller (p < 0.001) in the HRT technique than in the photographic method. In contrast, the HRT as compared to the photographic measurements showed significantly (p < 0.001) larger values for the relative width and relative area of the neuroretinal rim. The differences in measurements between both methods were maximum in the nasal part (p < 0.001) of the optic disc and minimum in the temporal disc region. CONCLUSION: In normal eyes of South Indians, neuroretinal rim measurements by the HRT and expressed as percentage of disc size measurements are significantly larger than rim measurements on disc photographs.