Abstract
Purpose :
Conflicting epidemiologic studies suggest that myopia may both increase and decrease the risk of glaucomatous visual field loss. To provide appropriate treatment to glaucoma patients, it is important to detect meaningful changes in the visual field, which requires distinguishing between visual field fluctuation and progression. Long-term visual field fluctuation is defined as the variability between two visual field tests performed on separate days on the same eye that cannot be attributed to a pathologic change. We performed a retrospective, observational clinical study to test the hypothesis that myopic glaucoma patients demonstrate more long-term visual field fluctuation than emmetropic glaucoma patients.
Methods :
Four or more 24-2 or 30-2 Humphrey visual field tests over several clinic visits were analyzed in 156 patients. Data including the visual field index (VFI) plot, mean deviation (MD), and threshold sensitivity on the glaucoma progression analysis were collected to quantify fluctuation. The sample was divided into two groups: 1. emmetropic glaucoma patients with a spherical equivalent refraction between +2 to -2 diopters and 2. high myopic glaucoma patients with a spherical equivalent refraction over -5 diopters. Within-patient within-eye fluctuation was calculated using root mean square error (RMSE).
Results :
RMSE testing between 78 myopic glaucoma patients and 78 emmetropic glaucoma patients found that myopic glaucoma patients demonstrated significant fluctuation for MD (p=0.006) and VFI (p=0.035). Although myopic patients showed greater fluctuation for MD (1.504±1.016, SEM=0.115) and VFI (0.037±0.045, SEM=0.005) compared to emmetropic glaucoma patients (MD = 1.125±0.652, SEM=0.074) (VFI=0.026±0.019, SEM=0.002), threshold sensitivity analyses did not reach statistically significant differences (p=0.054) between myopic (1.609±1.022, SEM=0.116) and emmetropic glaucoma patients (1.339±0.687, SEM =0.078). Additional statistical tests will be presented.
Conclusions :
The results for MD and VFI are consitent with the hypothesis that myopic patients demonstrate more visual field fluctuation than emmetropic glaucoma patients. Therefore, clinicians should incorporate more frequent visual field tests and a thorough examination of clinical findings such as optic nerve appearance, retinal nerve fiber layer thickness, and intraocular pressure to guide clinical decision making for myopic glaucoma patients.
This abstract was presented at the 2024 ARVO Annual Meeting, held in Seattle, WA, May 5-9, 2024.