Rate of visual field decay in glaucomatous eyes with acquired pits of the optic nerve

Background To evaluate the relationship between the presence of an acquired pit of the optic nerve (APON) and the rate of visual field (VF) decay in primary open-angle glaucoma (POAG). Methods Consecutive patients with POAG were screened for APON by three glaucoma specialists. A control group of POAG eyes without APON were matched with the APON group for factors such as age, gender, baseline intraocular pressure and baseline mean deviation (MD). The pointwise rate of change (PRC) was used for pointwise comparisons between the two groups. MD rate, Visual Field Index (VFI) rate and Glaucoma Rate Index (GRI) were used for global rate comparisons. We compared the proportions of eyes progressing in the groups with event-based guided progression analysis (GPA), MD, VFI and GRI criteria. Results Mean (SD) PRC was faster in the APON group -1.00 (±2.57) %/year compared with the control group -0.25 (±2.19) %/year; p<0.001. MD rate (-0.22 (±0.27) dB/year vs 0.03 (±0.41) dB/year; p=0.009), VFI rate (-0.81 (±0.86) %/year vs -0.05 (±1.0) %/year; p=0.04) and GRI (-12.27 (±16.27) vs -3.75 (±10.6); p=0.052) were all faster in the APON group compared with controls. The proportion of progressing eyes with GPA, MD, VFI and GRI was not significantly different between the two groups (p>0.1). Conclusions The presence of APON in patients with POAG is associated with focal, fast rates of VF decay. Identification of patients with APON should alert clinicians to the possibility of a fast rate of functional progression and to consider appropriately aggressive treatment of their glaucoma.