Colour vision in diabetic patients after photocoagulation treatment. A five-year follow-up

Colour vision of 60 diabetic patients (60 eyes) was studied after photocoagulation treatment in 1986-87. For the follow-up study 5 years later in 1991-92, 32 of the patients were available. The ages of the patients in the follow-up study varied from 28 to 64 years, the duration of diabetes from 19 to 35 years, the amount of laser spots from 200 to 3174, and the visual acuity from 0.4 to 1.0. As colour vision tests, the Standard Pseudo-isochromatic Plates part 2, Lanthony Tritan Album, Farnsworth Panel D 15, and box III of the Farnsworth-Munsell 100 hue test were used. Of the 32 eyes, 22 (68.8%) had the same results in the colour vision tests, 4 (12.5%) had better results, and 6 (18.8%) had worse results than 5 years earlier. Between Group 1 (colour vision the same or better than 5 years earlier, 26 eyes) and Group 2 (colour vision worse than earlier, 6 eyes) there was a significant difference in the age and in the level of the visual acuity of the patients. The changes in the lens, fundus or visual acuity during 5 years did not seem to have an effect in colour vision.