Evaluation of color vision and contrast sensitivity in diabetic patients without retinopathy

Abstract

Purpose: The purpose of this study is to evaluate the color vision and contrast sensitivity in diabetic patients without diabetic retinopathy, and to assess the color vision and contrast sensitivity in every diabetic patient before the occurrence of diabetic retinopathy and make it an integral part of routine examination. Materials and methods: A hospital based descriptive cross-sectional study was conducted at Aziz-Fatimah Hospital Faisalabad including 50 patients of age between 30 to 55 years. Information regarding duration of diabetes, diabetes status (controlled/uncontrolled), types of the diabetes was recorded. After taking complete history the visual acuity was measured with tumbling E chart and subjective refraction was performed. Then dilation fundus examination was performed with +78 D lens and fundus photograph was taken to evaluate diabetic retinopathy. On the next day Color vision and contrast sensitivity of the patients were assessed with Ishihara test and Pelli-Robson Chart Respectively. Results: There were 44% males and 56% females with the mean age of 48.42±5.15 years. Normal contrast sensitivity was observed in 34% (n=17) of the patients. However, 30% (n=15) of the patients had reduced contrast sensitivity, 28% (n=14) of the patients had poor contrast sensitivity and only 8% (n=4) patients had severe visual impairment. Color vision was observed normal in 68% (n=34) patients while 24% (n=12) of the patients had impaired color vision and only 8% (n=4) of the patients had sever visual impairment. There were 42% (n=21) diabetic patients with > 5 years history of diabetes, 38% (n=19) of diabetic patients with 5-10 years history of diabetes and 20% (n=10) of diabetic patients had <10 years history of diabetes. Type 1 diabetes were observed in 46% (n=23) and type 2 diabetes were observed in 48% (n=24). There were only 6% (n=3) of diabetic patients with dietary control. Most of the patients had controlled diabetes 64% (n=32) while uncontrolled diabetes were observed in 36% (n=18) patients. Conclusion: There were highly significant association of Status of Diabetes (Controlled/uncontrolled) and duration of diabetes with color vision and contrast sensitivity. There was no significant association of age and gender with color vision and contrast sensitivity. This study was helpful in detecting the early visual function compromised due to diabetes before the occurrence of diabetic retinopathy.