Relationship between severity of visual field loss at presentation and rate of visual field progression in glaucoma.

Abstract

To evaluate the relationship between severity of visual field (VF) loss at presentation and rate of VF progression in glaucoma. Clinic-based, retrospective study. We included 512 eyes of 310 primary glaucoma patients. We analyzed the VFs of all subjects of primary glaucoma who had >5 VFs between 1989 and 2008. Based on the mean deviation (MD), we classified the VF loss as mild (MD > -6 dB), moderate (MD ≤ -6 to ≥ -12 dB) or severe (MD < -12 dB). Guided Progression Analysis software which gives the rate of progression (ROP) of Visual Field Index per year was used to assess the ROP. Relationship between severity of VF loss at presentation and ROP. The median duration of follow-up was 6.8 years. The ROP increased (worsened) by 0.02% per year for every dB worsening of MD (P = 0.02) and for every year of increasing age (P = 0.001). Association between MD and ROP showed a significant positive relationship in mild (β = 0.18; P = 0.001) and a significant negative relationship in severe (β = -0.16; P<0.001) VF loss category. Association between MD and ROP was not significant in the moderate VF loss category (β = -0.05; P = 0.61). In early stages of glaucoma, the ROP worsened as the severity increased, but, in later stages of the disease, ROP became smaller as the severity increased. There is a need for better methods to detect progression in eyes with severe glaucomatous damage.