Abstract
Purpose :
The aim of this study was to assess a possible link between keratoconus (KC) occurrence and patients' smoking habits.
Methods :
We conducted a telephone survey among 80 KC patients who were treated from March 2016 until September 2017 by accelerated crosslinking (A-CXL) within our 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 (National Institute for Prevention and Health Education).
Results :
In total 62 patients with KC were analyzed, 41 were males and 21 were females.The mean age of diagnosis was 22 years (SD 5). The mean age at which A-CXL was performed was 23 years (SD 6). Out of the 62 patients, 22 (35%) reported to have allergies ; 6 (10%) patients reported family history of KC. Daily Smokers represented 19%, occasional smokers 8%, ex-smokers 21% and non-smokers 52%.
The mean age of when people started smoking was 17 years (SD 2). The mean number of daily smoked cigarettes was 8 (SD 6). Ex-smokers stopped at a mean age of 24 years (SD 4). The observed rates (KC patients) and expected rates (general population) of daily smokers were respectively 19% and 39% at the time of the survey, 24% and 35% at the time of the A-CXL treatment and most importantly 31% and 35% at the time of diagnosis.
Conclusions :
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. Our data doesn’t seem to suggest a significant protective effect on the occurrence of KC.
A prospective cohort is needed to investigate whether the observed diminution of smoking between diagnosis and CXL treatment is related or not to the evolution of the KC.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.