Position of the central retinal vessel trunk and pattern of remaining visual field in advanced glaucoma

Background To investigate the association between the position of the central retinal vessel trunk (CRVT) in the optic nerve head and the pattern of remaining visual field and thickness of the retinal nerve fibre layer (RNFL) in end-stage glaucoma. Methods The clinical observational study included patients with end-stage glaucoma with a remaining central visual field island (CI-group) or temporal visual field remnant (TI-group). The position of the CRVT exit on the lamina cribrosa was evaluated on optic disc photographs. The RNFL thickness was measured by optical coherence tomography. Results The study included 21 glaucoma patients with a remaining central visual field island and 22 glaucoma patients with a temporal visual field remnant. Both groups did not differ significantly in age, gender, refractive error, central corneal thickness, axial length and mean RNFL thickness. RNFL in the temporal region (48.1 +/- 5.5 mu m vs 37.2 +/- 7.9 mu m; p<0.001) was significantly thicker, and RNFL in the nasal region (41.6 +/- 8.3 mu m vs 48.0 +/- 7.8 mu m; p=0.01) was significantly thinner in the CI-group than TI-group. The CRVT was located in the temporal disc part significantly more often in the CI-group than in the TI-group (6/21 vs 0/22; p=0.009). The distance from the CRVT to the temporal disc border expressed as percentage of total disc diameter was significantly smaller in the CI-group than in the TI-group(0.55 +/- 0.07 vs 0.79 +/- 0.08; p<0.001). Conclusions The pattern of perimetric loss was associated with the CRVT position: eyes with a central visual field island tended to have the CRVT in the temporal optic disc region.