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Abstract #18178 Published in IGR 9-2
Correlation between optic disc area and retinal nerve fiber layer thickness: A study on scanning laser polarimetry with variable corneal compensation
Da Pozzo S; Iacono P; Michelone L; Paoloni M; Ravalico GGraefe's Archive for Clinical and Experimental Ophthalmology 2007; 245: 511-515
PURPOSE: To evaluate if a significant increase of the peripapillary retinal nerve fiber layer (RNFL) thickness can be measured in a sample of healthy eyes by means of scanning laser polarimetry with variable corneal compensation (GDx-VCC) as the optic disc (OD) area increases. METHODS: One eye each of 232 healthy subjects (mean age: 57.8 years; range:40-70) was considered. Temporal-superior-nasal-inferior-temporal average (TSNIT Avg) and OD area (area within the ellipse placed on inner border of peripapillary scleral ring) values were collected. Ellipse horizontal and vertical diameters provided on printout were used to estimate OD area using the equation: OD area = π x horizontal radiusxvertical radius. TSNIT Avg values were plotted against OD area and a multiple linear regression including age calculated. RESULTS: Mean OD area was 2.19 mm2 ± 0.45 (range: 1.23-3.59) and mean TSNIT Avg was 54.3 μ ± 3.2 (range: 45.8-61.8). Multiple linear regression equation was TSNIT Avg = 57.7-0.096xOD Area-0.055xAge (Pearson r = -0.146: p = 0.086) CONCLUSION: In our sample of healthy eyes, no significant correlation was found between TSNIT Avg and OD area. In spite of a shorter distance between OD and measurement ellipse margins, larger discs did not necessarily show a thicker RNFL. Probably the large inter-subject variability for RNFL thickness, and then for axonal count, was a predominant factor over OD area.
Dr. S. Da Pozzo, Eye Clinic, University of Trieste, Piazza dell’Ospedale 1, 34129, Trieste, Italy. stefano34127@lycos.it
Classification:
6.9.1.2 Confocal Scanning Laser Polarimetry (Part of: 6 Clinical examination methods > 6.9 Computerized image analysis > 6.9.1 Laser scanning)
2.13 Retina and retinal nerve fibre layer (Part of: 2 Anatomical structures in glaucoma)
2.14 Optic disc (Part of: 2 Anatomical structures in glaucoma)