Premium
Prevalence of significant pre‐clinical contrast sensitivity loss in diabetics
Author(s) -
Gilchrist Jim,
Pope Richard,
Dhanesha Usha,
Young Sally,
Horsley Clare
Publication year - 1997
Publication title -
ophthalmic and physiological optics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.147
H-Index - 66
eISSN - 1475-1313
pISSN - 0275-5408
DOI - 10.1046/j.1475-1313.1997.97807302.x
Subject(s) - medicine , diabetic retinopathy , confidence interval , visual acuity , fundus (uterus) , contrast (vision) , ophthalmoscopy , ophthalmology , diabetes mellitus , retinopathy , eye disease , population , fundus photography , optometry , retinal , fluorescein angiography , endocrinology , optics , physics , environmental health
Aim: To estimate the prevalence of impaired contrast sensitivity (CS) in diabetic patients with normal visual acuity and no clinical detectable retinopathy. Methods: We measured CS in 75 diabetics with visual acuity of logMAR 0.0 or better, no evidence of retinopathy by direct ophthalmoscopy and fundus photography, and no evidence of cataract. The sample comprised 27 IDDM (15–44 years), and 48 NIDDM (35–71 years). The CS of each patient was measured with sinusoidal gratings at 2, 4 and 8 cdeg −1 using a two‐alternative forced‐choice staircase procedure, and the data were compared with CS values from age‐related non‐diabetic patients. A decision was made for each diabetic that CS was either normal or impaired, based on whether that individual's CS fell more than 2 standard deviations (Criterion A) or 3 standard deviations (Criterion B) below the age‐related non‐diabetic mean value. Results and conclusions: Estimated proportions, averaged across all spatial frequencies, of diabetic patients with impaired CS were: 28% by Criterion A and 15% by Criterion B. Population estimates (95% confidence intervals) for the prevalence of significant pre‐clinical CS loss in diabetics based on these results are: 18–38% using Criterion A and 7–23% using Criterion B.