RELATIONSHIP BETWEEN CONTRAST SENSITIVITY AND METABOLIC CONTROL IN DIABETICS WITHOUT RETINOPATHY

Abstract

BACKGROUND: Contrast sensitivity is the capacity to detect minor changes in luminance between regions that do not have distinct borders.However, visual acuity evaluates the sharpness of one's eyes at a specific distance. High contrast optotypes, which consist of black text on a white backdrop, are used to evaluate this. The fact that contrast sensitivity, a measure of visual quality, often decreases at an earlier age than visual acuity does is generally acknowledged. The current diabetes epidemic in India is largely attributable to diabetic retinopathy, a vision-threatening complication of diabetes mellitus. Research suggests that retinal neurodegeneration occurs in the early stages of diabetic retinopathy, despite the fact that the condition is characterised as a microvascular disease.Visual impairments such as reduced contrast sensitivity, changed colour perception, and altered temporal perception can be caused by retinal neurodegeneration. Such deficiencies might manifest prior to alterations in visual acuity and vascular architecture .Detecting early visual functional alterations in lower contrast situations may be beyond the capabilities of the current screening techniques for diabetic retinopathy, which primarily evaluate the morphologic integrity of the retina and retinal circulation. Therefore, the purpose of this study is to ascertain whether metabolic control and contrast sensitivity are associated in Type 2 diabetics who do not have retinopathy. METHODS: From September 2022 to December 2023, a cross-sectional study was carried out on a minimum of 53 patients who met the inclusion criteria at R. L. Jalappa Hospital and xvii Research in Kolar. The study was approved by the Institutional Ethical Committee of Sri Devaraj Urs Medical College, and the subjects were provided written informed consent. The period of diabetes and diabetic control were recorded after collecting a brief history of the patient's eyes and overall health, as well as their treatment for the condition. Visual acuity, anterior and posterior segment evaluation, and demographic data were all part of the clinical examination that each patient underwent. A thorough evaluation of the retina was carried out in order to exclude the possibility of diabetic retinopathy. Exclusion criteria for participation in the study include the presence of intra retinal haemorrhage or microaneurysms, the first sign of diabetic retinopathy seen through ophthalmology.Estimations were made for fasting blood sugar, postprandial blood sugar, and glycated haemoglobin (HbA1C). Using the identical lighting conditions, we measured contrast sensitivity at a distance of 1 metre using a Pelli-Robson chart. Log contrast units are used to quantify contrast sensitivity. The contrast sensitivity is negatively correlated with the score. RESULTS: The present study enrolled 53 patients and their mean age was 60.16±7.80 years and ranged from 40 to 70years.The mean fasting blood glucose was 127.28±40.75 mg/dl and the post prandial blood glucose was 174.37±59.52 mg/dl. The three months glycemic control marker HbA1c was assessed and the mean was 7.72±1.85.The mean duration of diabetes was 7.21±4.37 years The mean contrast sensitivity for right eye was 1.57±0.37 which indicated some visual impairment. Similarly the left eye also showed the same (1.56±0.37). The negative xviii correlation was observed in the present study which indicated that as the duration of diabetes increased with poor glycemic control, the contrast sensitivity decreased on both right eye (r=0.7097; P<0.0001) and left eye (r=-0.6990; P<0.0001) . CONCLUSION: In conclusion, our study highlights the critical interplay between diabetes duration, glycemic control, and visual impairment. As the duration of diabetes increased; contrast sensitivity decreased on both eyes significantly (P<0.0001).Similarly, both eyes contrast sensitivity had a negative correlation with HBA1c levels, which revealed that as the glycemic control progressed to poor control, the contrast sensitivity progressed to visual impairment. The significant correlations found in this study should encourage healthcare providers to focus on comprehensive diabetes management strategies to prevent or delay the onset of visual disabilities in diabetic patients.