Optic disc progression and rates of visual field change in treated glaucoma

Abstract

Purpose: To investigate the relationship between optic disc progression and rates of visual field (VF) change in patients with treated glaucoma.

Methods: Glaucoma patients with repeatable VF loss, ≥8 SITA-Standard 24-2 VF tests and good quality optic disc stereophotographs evaluated over a 10-year period were included. Optic disc photographs were reviewed for signs of glaucoma progression (neuroretinal rim change, widening of retinal nerve fibre layer defect, disc haemorrhage and enlargement of beta-zone parapapillary atrophy) by two glaucoma specialists masked to their temporal sequence. Disagreements were adjudicated by a third grader. VF progression was evaluated using automated pointwise linear regression (PLR) and defined as at least two adjacent test points progressing >1.0 dB/year at p < 0.01. VF progression outcomes were compared with photograph review results.

Results: Three-hundred and eighty nine eyes (389 patients; mean age 64.9 ± 13.0 years; mean baseline MD, -7.1 ± 5.1 dB) were included. Most patients had primary open angle glaucoma (54%). Eighty-two eyes (21%) had confirmed optic disc progression and 115 eyes (29%) met the VF PLR criteria. Eyes with documented optic disc progression had more rapid rates of VF change (-0.66 ± 0.7 versus -0.36 ± 0.7 dB/year, p < 0.01) and met the VF PLR endpoint more often (univariate OR = 1.85, p = 0.02; multivariate OR = 1.78, p = 0.03) than eyes without optic disc progression. There was moderate spatial consistency between the location of the optic disc progression and the hemifield with more rapid progression (81%, kappa = 0.40).

Conclusions: Treated glaucomatous eyes with documented optic disc progression are at increased risk of diminished visual function over time and may require more aggressive therapy to prevent future vision loss. Among the indicators of structural progression, disc haemorrhage was the single most significant predictor for VF deterioration.