Certain studies reported that cigarette by-products may make the cornea more rigid, suggesting that it could lead to "natural" CXL of collagen fibers, hence a protective effect for KC. Others have reported that cigarette smoking causes no significant changes in the corneal biomechanics. The aim of this study was to assess a possible link between keratoconus (KC) occurrence and patients' smoking habits.

a telephone Survey was performed among 80 KC patients who were treated from March 2014 until September 2017 by accelerated crosslinking (A-CXL) within the ophthalmology department. From the 80 people we phoned, 62 answered. Our questions were regarding family history, allergic history, and smoking habits. Family history was considered positive if a first-degree or second-degree relative had been diagnosed with KC. Allergies toward any kind of external factors were marked as positive. Patients' smoking habits were recorded and classified into regular, occasional, ex-smoker and non-smoker. The results were confronted to those of the general population by indirect standardization over age and sex according to the "Baromètre Santé 2010" INPES survey (French Nation Institute for Prevention and Health Education).

Inclusion Criteria:

• patients suffering from Keratoconus and needing Cross-linking therapy

Exclusion Criteria:

• none

patients suffering from Keratoconus and needing Cross-linking therapy