Differentiating Normal Visual Fields In Eyes With Glaucomatous Optic Neuropathy And Healthy Eyes.

Abstract

Abstract: : Purpose: To determine if normal standard automated perimetry (SAP) visual fields in eyes with glaucomatous optic neuropathy (GON) can be differentiated from normal fields of healthy eyes. Methods: Normal visual fields of 35 eyes with GON and 170 healthy eyes from a prospective longitudinal study were examined. Normal SAP full–threshold visual fields had glaucoma hemifield test (GHT) result within normal limits, a normal pattern standard deviation (PSD) and a normal classification by an unsupervised learning algorithm. Normal percentile ranks of total deviations (TD) values at each of 52 locations of the Humphrey 24–2 test pattern were calculated from a separate normative database of 348 eyes. The number of locations exceeding the sensitivity at each percentile rank (5% to 100% in 5% increments) was calculated for each field. Average TD values at each location were compared for GON and healthy eyes. Results: PSD was significantly lower (p<5%) in eyes with GON (mean±SD; 1.8±0.1) than healthy eyes (1.6±0.1), as was the mean deviation (GON; –0.5±0.2; healthy eyes, 0.2±0.1). The distribution of number of participants and number of locations with a TD exceeding the percentile rank differed between GON and healthy eyes at percentile ranks of 55% and higher. TD scores at 24 locations were significantly worse in GON eyes than healthy eyes in superior nasal, superior arcuate and temporal blindspot locations. Conclusions:Despite being normal, visual fields from eyes with GON have lower sensitivity compared to healthy eyes, particularly in locations typically affected in early glaucoma. It may be possible to use this information to improve early detection.

Keywords: visual fields • perimetry