Relationship between corneal sensitivity and diabetic retinopathy among diabetics attending a Nigerian Teaching Hospital.

Purpose: To determine the relationship between corneal sensitivity and diabetic retinopathy among diabetics attending Lagos University Teaching Hospital, compared to their age-sex-matched non-diabetics, with a view to proposing its use as a screening tool for diabetic retinopathy.

Methods: The study was a hospital-based comparative cross-sectional study among diabetics aged 25-65 years and their age-sex-matched non-diabetics at Lagos University Teaching Hospital, Lagos, Nigeria. Interviewer-based questionnaire was administered. Corneal sensitivity was assessed with Cochet-Bonnet aesthesiometer. Dilated fundoscopy examination was carried out using slit-lamp bio-microscope with 78D lens and binocular indirect ophthalmoscope.

Results: A total of 120 diabetics and 120 age- and sex-matched non-diabetics were enrolled into the study. Among the diabetics, the mean corneal sensitivity was 52.6 ± 6.9 mm, which was statistically lower than among non-diabetics - 58.2 ± 3.0 mm (p-value < 0.05). Twenty-one percent of the diabetic respondents had diabetic retinopathy. The mean cornea sensitivity was statistically lower among diabetics who had developed diabetic retinopathy compared to those with no diabetic retinopathy (48.9 ± 7.3 vs. 55.3 ± 5.4, p < 0.05). The sensitivity and specificity of the aesthesiometer for proliferative diabetic retinopathy at 55 mm cut-off were 100% and 58%, respectively.

Conclusion: Cornea sensitivity was significantly lower among diabetics with retinopathy compared to those without retinopathy. Also, the degree of cornea sensation loss among diabetics reduced significantly with severity of diabetic retinopathy. Larger validity studies need to be conducted to further assess the use of corneal aesthesiometer as a screening tool for diabetic retinopathy among non-ophthalmologists and other cadres of health workers.