Abstract
Purpose:
Visual field index (VFI) is a recently introduced summary parameter. Before it is widely adapted, it needs to be further characterized and compared with familiar indices used in glaucoma management, specifically mean deviation (MD). To characterize VFI in cases of advanced glaucoma by comparing it to MD and criteria of blindness according to the US Social Security and World Health Organization (WHO).
Methods:
Visual fields of glaucoma patients with MD worse than -12 dB were prospectively included. VFI was compared to MD and criteria of blindness.
Results:
Visual fields of 66 eyes of 54 patients were included. MD ranged from -12.15 to -31.4, VFI ranged from 0% to 76%. These parameters exhibited excellent correlation with R2=0.96. VFI corresponding to MD of -15 , -20, -22, and -25 was 55%, 40% , 35%, and 24% respectively. Correlation between VFI and the widest remaining central visual field diameter was only demonstrated in the later, more severe, stages of glaucoma.
Conclusions:
VFI was found to be in excellent correlation with MD across the spectrum of glaucomatous visual loss. However, its “intuitive” presentation may underestimate the visual loss. We recommend that clinicians aim to keep VFI above 50-60% for the remainder of the patient’s lifetime in order to preserve functional vision.
Keywords: 758 visual fields •
460 clinical (human) or epidemiologic studies: health care delivery/economics/manpower •
495 depth