Difference in the properties of retinal nerve fiber layer defect between superior and inferior visual field loss in glaucoma

PURPOSE: To investigate the patterns of retinal nerve fiber layer (RNFL) defects in mean deviation-matched early glaucomatous eyes with either superior or inferior visual hemifield loss.

METHODS: Seventy-five open-angle glaucoma patients with isolated parafoveal scotoma (PFS) within a central 10° of fixation, and 62 patients with isolated peripheral nasal scotoma (PNS) in the nasal periphery outside 10° of fixation were enrolled if the scotoma involved only one hemifield. The relationship between the mean threshold sensitivity (MS) of each corresponding VF sector and optical coherence tomography-measured RNFL thickness was assessed by logarithmic regression analysis. The angular widths and locations of the RNFL defects were measured from red-free fundus photographs.

RESULTS: Eyes with superior PFS showed a significant relationship between RNFL thickness and corresponding MS at clock-hours 7 and 8 while eyes with inferior PFS had significant relationship at clock-hours 9, 10, and 11. Eyes with superior PNS displayed a significant relationship between RNFL thickness and MS at clock-hour 7 while eyes with inferior PNS showed significant relationship at clock-hours 11 and 12. Overall, fundus photographs-measured RNFL defect associated with inferior hemifield loss (inferior PFS + PNS) was significantly wider and closer to the horizontal meridian than those with superior hemifield loss (superior PFS + PNS) (P = 0.032 and 0.009, angular width and location, respectively).

CONCLUSIONS: A superior RNFL defect associated with inferior hemifield loss was wider and was located closer to the horizontal meridian of the optic disc than an inferior defect with superior field loss, particularly in patients with central VF loss.