Abstract
Abstract: :
Purpose: To study topographic relationships between local perimetric field losses and deviation from normal nerve fiber layer thickness. Methods: Seventy–three glaucomatous eyes of 73 patients were studied with octopus (G1, 3 phase) and polarimetry (optic disc & macular image). All patients had localized perimetric losses. Patients with diffuse perimetric defects, large optic discs, or significant hourglass pattern in the macular image were not included. Thickness values of the retinal nerve fiber layer were determined in 14 upper and 14 lower sectors as well as nasally and temporally as provided from the Gdx (version 4000). Seventy–five healthy control subjects served to determine local thickness deviation in the sectors for all subjects. Analyses were calculated in nerve fiber bundle related areas as defined by Weber (1991). Due to a non linear association between perimetric defects and thickness deviation non–parametric tests were used. In the correlation analyses only data of the glaucoma patients were taken into account. Results: Visual field defects were highest in upper and lower visual field areas abutting the nasal meridian. However, thickness loss of nerve fiber layer was highest in more circumferential upper and lower nerve fiber bundles. Correlations of local mean defects and corresponding thickness deviation showed a clear association for most areas where relationships were expected. The correlation coefficients were significant after Bonferroni correction for arcuate superior (p<0.01) and inferior (p < 0.05) visual field zones but not temporally and the area of lower nasal step. Conclusions: The study delivers a correspondence map between local visual field defects and associated reduction of the nerve fiber layer. This might be useful for documentation and follow–up of localized perimetric field losses.
Keywords: imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • perimetry • nerve fiber layer