Abstract
OBJECTIVE: To determine the impact of tobacco chewing on corneal endothelial structure in patients with diabetes mellitus (DM). METHODS: Corneal endothelial parameters (endothelial cell count, ECD; coefficient of variation, CV; hexagonality, Hex, and central corneal thickness, CCT) were analysed in 1234 eyes of 1234 patients using non-contact specular microscopy (EM 4000 Tomey Nishi-Ku, Nagoya, Aichi, Japan). The study group (with a present history of tobacco chewing) comprising of 948 subjects, with 473 having DM was compared with age and gender-matched control group comprising of 286 subjects (139 having DM) with no history of tobacco use in any form. RESULTS: Tobacco chewers had a significantly reduced ECD (P = 0.024) and Hex (P = 0.009) as compared with non-chewers. Similar results were noted in ECD (P = 0.004) and Hex (P = 0.005) in patients with DM. Tobacco chewers had a significantly decreased ECD values among males, HbA1C ≤ 7.5% and duration of DM ≤ 20 years, and significantly decreased Hex among those with >50 years of age, females, and duration of DM > 20 years. The CV and CCT values were comparable between the study and the control groups. Tobacco chewers showed a significant association of ECD with age, HbA1C, and duration of DM; CV with HbA1C; Hex with age and duration of DM; and CCT with gender, age, HbA1C and duration of DM. CONCLUSIONS: Tobacco chewing may negatively impact corneal health, especially confounded by additional factors like age and DM. These factors must be accounted for in the pre-operative evaluation of such patients prior to any intra-ocular surgery.