Humphrey visual field and frequency doubling perimetry in the diagnosis of early glaucoma.

ABSTRACT

PURPOSE: To compare Humphrey Visual Field Analyzer (HVF) and Frequency Doubling Perimetry (FDP) testing in the diagnosis of early glaucoma. METHODS: We performed HVF (24-2 standard full threshold) and FDP (N-30) evaluations in 34 consecutive patients with early primary glaucoma and 96 normal subjects. Early glaucoma was defined on the basis of disc changes of glaucoma; the mean deviation on white-on-white perimetry had to be no worse than 6 decibels. Glaucomatous optic neuropathy was defined as a combination of cup-disc asymmetry of more than 0.2, notching, excavation, thinning or pallor of superior or inferior neuroretinal rims, retinal nerve fibre layer defects of the wedge or diffuse type and neuroretinal rim haemorrhage. Both the glaucoma patients and normal subjects had vision better than 6/9 with correction. They had no media opacities other than early nuclear sclerosis and no fundus pathology. Further, normal subjects were free of systemic diseases known to affect the retina or optic nerve. The sensitivity and specificity of HVF and FDP were calculated. RESULTS: There were 44 eligible eyes among the 34 subjects. The glaucomatous disc findings included notch (n=8), pallor (n=21), thinning (n=23) and haemorrhage (n=1) of the neuroretinal rim. The sensitivity and the specificity of the HVF were 52.3% and 57.3% respectively. The sensitivity and the specificity of FDP were 65.9% and 61.5% respectively. CONCLUSION: The difference between FDP and HVF in the diagnosis of early glaucoma is not marked.