IMPAIRED CONTRAST SENSITIVITY IN ADOLESCENTS AND YOUNG TYPE-1 (INSULIN-DEPENDENT) DIABETIC-PATIENTS WITH MICROALBUMINURIA

We compared neurosensorial visual function by psychophysical tests (ma cular recovery time and contrast sensitivity) in two well matched grou ps of young Type 1 (insulin-dependent) diabetic patients with micro- a nd normoalbuminuria, respectively. The patients had normal visual acui ty (greater than or equal to 1.0) and either no retinopathy or non-pro liferative retinopathy. Thirty patients with microalbuminuria (albumin excretion greater than or equal to 15 mu g/min in a least two out of three timed overnight urine samples) were matched (age, diabetes durat ion, mean one-year HbA(1c), gender) with normoalbuminuric (n = 27) pat ients. Retinopathy (50 degrees colour fundus photography) was assessed by counting microaneurysms and hemorrhages as 'red spots'. Contrast s ensitivity was examined for the spatial frequencies of 1.5, 3, 6, 12 a nd 18 cycles per degree (cpd). Macular recovery time (nyctometry) refe rs to the time-related (2 min) ability of the retina to regain visual acuity following exposure to bright light (photostress). Contrast sens itivity score was reduced in patients with microalbuminuria compared t o those without; 18 cpd (mean and 95% confidence intervals): [4.2 (3.8 -4.7) vs 5.0 (4.6-5.4), p = 0.03]. Macular recovery performance was no t significantly reduced: [21.0 arbitrary units (17.5-24.6) vs 26.0 (22 .6-30.7), p = 0.12]. We conclude that impaired contrast sensitivity in dependent of background retinopathy is shown in a group of young Type 1 (insulin-dependent) diabetic patients with low-grade microalbuminuri a compared to a group of patients with normoalbuminuria.