Visual field progression differences between normal-tension and exfoliative high-tension glaucoma

Abstract

Purpose: To compare the pattern, location, and rate of visual field (VF) change in normal-tension (NTG) and exfoliative high-tension glaucoma (XHTG).

Methods: Records of all patients with glaucoma in the New York Glaucoma Progression Study with five or more VF tests were reviewed. Patients were divided into NTG (all known IOP < 21 mm Hg) and XHTG (untreated IOP >or= 21 mm Hg) groups. Automated pointwise linear regression analysis determined global and localized rates of change.

Results: There were 139 NTG and 154 XHTG eyes. Patients with XHTG were significantly older than those with NTG (mean +/- SD: 72.6 +/- 9.4 years vs. 62.7 +/- 12.8 years, P < 0.01), had higher mean IOPs (16.5 +/- 3.2 mm Hg vs. 13.3 +/- 2.0 mm Hg, P < 0.01) and greater central corneal thickness (CCT, 544.0 +/- 35.7 microm vs. 533.9 +/- 35.9 microm; P = 0.01). During a similar period, XHTG progressed globally almost twice as rapidly as did NTG (-0.64 +/- 0.7 dB/y vs. -0.35 +/- 0.3 dB/y, P < 0.01), which became nonsignificant after adjustment for differences in age, mean IOP, and CCT. In a multivariate model, variables significantly associated with progression were higher mean IOP (odds ratio [OR]: 1.09, P = 0.03) and decreased CCT (OR/40 mum thinner: 1.37, P = 0.03). Progression within the paracentral VF was more common in the NTG group (75% vs. 57.3%, P = 0.04). The most important factor associated with paracentral progression among eyes that reached a progression outcome was the diagnosis of NTG.

Conclusions: XHTG and NTG eyes progress at a similar global rate after adjustment for differences in IOP, CCT, and age. However, NTG eyes progress more often in the central VF, independent of other factors. Glaucoma surveillance in eyes with open-angle glaucoma and statistically normal IOP should include periodic assessment of the central field.