IMPACT OF AGE, VARIOUS FORMS OF CATARACT, AND VISUAL-ACUITY ON WHOLE-FIELD SCOTOPIC SENSITIVITY SCREENING FOR GLAUCOMA IN RURAL TAIWAN

Objective: To evaluate the impact of age, various forms of cataract, a nd visual acuity on whole-field scotopic sensitivity screening for gla ucoma in a rural population. Design: Clinic-based study with populatio n-based recruitment. Setting: Jin Shan Township near Taipei, Taiwan. S ubjects: Three hundred forty-six residents (ages, greater than or equa l to 40 years) of Jin Shan Township. Interventions: Whole-field scotop ic testing, ophthalmoscopy with dilation of the pupils, cataract gradi ng against photographic standards, and screening visual field testing in a random one-third subsample. Main Outcome Measures: Whole-field sc otopic sensitivity (in decibels) and diagnostic status as a case of gl aucoma, glaucoma suspect, or normal. Results: Participants in Jin Shan Township did not differ significantly in the rate of blindness, low v isual acuity, or family history of glaucoma from a random sample of no nrespondents. Scotopic sensitivity testing detected 100% (6/6) of subj ects with open-angle glaucoma at a specificity of 80.2%. The mean +/- SE scotopic sensitivity for six subjects with open-angle glaucoma (32. 78 +/- 1.51 dB) differed significantly from that of 315 normal individ uals (38.51 +/- 0.22 dB), when adjusted for age and visual acuity (P = .05, t test). With linear regression modeling, factors that correlate d significantly with scotopic sensitivity were intraocular pressure, s creening visual field, best corrected visual acuity, presence of corti cal cataract, and increasing age, Conclusion: Although cataract affect s the whole-field scotopic threshold, it appears that scotopic testing may be of value in field-based screening for glaucoma.