Abstract
Purpose:
Randomized glaucoma trials (RCTs) have used automated perimetry to measure visual field (VF) changes to determine outcomes, concluding that intraocular pressure (IOP) plays a key role in glaucoma onset and progression. Although 50% of retinal ganglion cells are located in the macula, this area is underrepresented in conventional perimetry. Given the lack of information in the literature regarding central vision loss and IOP, we investigated the association between rates of best corrected visual acuity (BCVA) loss, 10-2 progression, and IOP in patients with established glaucoma.
Methods:
This observational cohort study included patients with glaucomatous optic neuropathy and reproducible VF defects on SITA-Standard 24-2 tests. All patients had paracentral VF damage and were followed with 24-2 and 10-2 perimetry. Patients with fewer than 5 10-2 VF during follow-up were excluded. We investigated the association between IOP and changes of BCVA (LogMAR) and tested the association between rates of 10-2 mean deviation (MD) progression and decline in BCVA. Mixed linear models were used for statistical analysis.
Results:
176 eyes (142 patients, mean age, 60.7±10.6) followed for 5.2±4.4 years were included. Mean baseline BCVA was 0.19±0.2 (=20/30 Snellen). The mean rate of 10-2 MD progression was -0.47±0.6 dB/yr. The mean rate of LogMAR increase was 0.013±0.03 units/year, translating to a decline in BCVA from 20/30 to 20/40 during follow-up. Variables significantly associated with decline of BCVA were worse baseline MD (P<0.001), follow-up IOP (P=0.024), baseline IOP (P=0.001), peak IOP (P=0.017), and worse baseline BCVA (P<0.001). BCVA change was significantly associated with MD rates of progression (P<0.001).
Conclusions:
This is the first study to demonstrate that IOP reduction prevents not only conventional perimetric progression as shown in RCT but also slows the rate of BCVA deterioration and central field loss in glaucoma. Clinicians should not overlook changes in BCVA even if 10-2 VFs remain stable.
Keywords: 758 visual fields •
568 intraocular pressure •
754 visual acuity