Incidence and prevalence of short wavelength automated perimetry deficits in ocular hypertensive patients

Abstract

PURPOSE: To determine the prevalence and incidence of short wavelength automated perimetry deficits in comparison to standard automated perimetry deficits in patients with ocular hypertension. METHODS: Five hundred eyes of 250 patients with ocular hypertension were recruited into a prospective, longitudinal study and tested with standard automated perimetry and short wavelength automated perimetry annually for 5 years. Both eyes of 60 normal subjects, 21 to 85 years of age, were used to establish normative data for short wavelength automated perimetry and standard automated perimetry. This allowed independent evaluation of left and right eyes of patients. All normal data were corrected for age, and short wavelength automated perimetry results were corrected for lens transmission. The lowest fifth and first percentiles for the normal observers were derived for the 10 glaucoma hemifield test zones for short wavelength automated perimetry and standard automated perimetry. Visual fields were considered outside normal limits if two glaucoma hemifield test zones were below the normal fifth percentile or one glaucoma hemifield test zone was below the normal first percentile. RESULTS: Baseline prevalence of short wavelength automated perimetry and standard automated perimetry deficits were 9.4% and 1.4%, respectively. During the study, incident rates of field loss were 6.2% (1.23% per year) for short wavelength automated perimetry and 5.9% (1.18% per year) for standard automated perimetry. Once abnormal, 80% of short wavelength automated perimetry fields remained abnormal on the next examination, whereas only 45% of abnormal standard automated perimetry fields remained abnormal. New short wavelength automated perimetry deficits in ocular hypertensives were more prominent and more persistent than new standard automated perimetry deficits. CONCLUSIONS: Our findings are consistent with the interpretation that short wavelength automated perimetry deficits occur before standard automated perimetry deficits in glaucoma. The similar incidence rates suggest that both standard automated perimetry and short wavelength automated perimetry are monitoring the same underlying glaucomatous disease process.