Tobacco smoking in crosslinked keratoconus patients.

The aim of this study was to evaluate the possibly protective link of smoking in keratoconic patients treated with accelerated cross-linking.A telephone survey was conducted among 80 KC patients treated by accelerated cross-linking (A-CXL). The questions focused on general history, possible atopy and smoking habits. Results were compared to those of the general population by indirect standardization by age and sex according to the French national INPES survey.Sixty-two patients with KC were analyzed. The mean age at diagnosis was 22 years (SD 5). The mean age at which A-CXL was performed was 23 years (SD 6). Daily smokers represented 19 %, occasional smokers 8 %, ex-smokers 21 % and non-smokers 52 %. The mean age at which the patients began smoking was 17 (SD 2) years. Ex-smokers quit at a mean age of 24 (SD 4) years. The observed rates and expected rates of daily smokers were 19 % and 39 % respectively at the time of the survey (P=0.01), 24 % and 35 % at the time of the A-CXL treatment (P=0.10) and 31 % and 35 % at the time of diagnosis (P=0.58). The decrease in the rate of observed daily smokers over time was significant (P=0.02).Our data does not appear to suggest a significant protective effect of smoking on the occurrence of KC. It shows a lesser proportion of smokers in KC patients after A-CXL, but this difference did not exist at the time of KC diagnosis.