Abstract
Purpose:
To determine if there is any relation between structural and functional changes after intraocular pressure (IOP) reduction in patients with glaucoma.
Methods:
Patients with glaucoma in whom a pressure-lowering event was to be initiated were included. All patients received a pressure-lowering intervention - medicines, laser or surgery. Prior to the intervention, they performed a 24-2 SITA standard visual field examination, Spectralis optical coherence tomography (OCT) imaging test (fast retinal nerve fiber layer and macular protocols) and visual evoked potential (VEP) exam using the Diopsys NOVA-VEP Vision Testing System. For patients with initial IOP ranging between 22-32mmHg, these tests were repeated after 1-2 months, 4-6 months, and 9-12 months after IOP reducing interventions. For patients with initial IOP ≥33mmHg, after obtaining the baseline examinations (visual field, OCT and VEP), they had their IOP acutely lowered. The studies were then repeated one hour, one day and three months following the acute pressure lowering.
Results:
Forty seven patients (58 eyes) were included in the study, 38 patients with initial IOP ranging between 22-32mmHg and 9 patients with initial IOP ≥33mmHg. There was a significant change in IOP over time (P<0.001 for both groups). Change in IOP was significantly associated with change in cup volume (P=0.037) and change in rim area (p=0.032) after the first follow-up visit, for both groups combined. The association between change in IOP and change in VEP amplitude high contrast approached significance after the first follow-up visit in the IOP>33mmHg group (P=0.06). Change in OCT retinal nerve fiber layer over time approached significance in the IOP>33mmHg group (P=0.09).
Conclusions:
With a marked reduction of IOP in glaucomatous eyes there were early structural changes confirmed by OCT imaging but no significant changes were noted with functional tests - perimetry and VEP.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
507 electrophysiology: clinical •
758 visual fields