Abstract
Purpose: :
Acanthamoeba keratitis (AK) affects all ages, yet teenagers are disproportionately affected. The cornea has a biologic adaptive response to contact lens use with time; in addition, recent initiators of contact lens use may have different hygiene practices. Results from the Centers for Disease Control and Prevention AK case-control study presented at the Food and Drug Administration Ophthalmic Devices Advisory Panel Committee meeting in 6/08 demonstrate a statistically significant association between AK and contact lens use <=5 years, adjusting for use of Advance Medical Optics Complete MoisturePlus and solution reuse (AMO-CMP; available at http://www.fda.gov/ohrms/dockets/ac/08/slides/2008-4363s1-03-VERANI-CDC.pdf). The purpose is to confirm if subjects with contact lens use <=5 years may be more likely to develop disease.
Methods: :
240 Chicago area case-control study subjects recruited from the UIC Cornea Service participated, including 65 AK cases diagnosed 6/1/03 - 6/1/08 matched to 175 controls on lens use, age (± 5 years) and date of service (± 1 month). Logistic regression was used to estimate the odds ratio (OR) and 95% confidence interval (CI) between lens use <=5 years and AK among soft lens users, as well as age-stratified ORs (13 - 18 vs. 19 - 74), adjusting for AMO-CMP use and solution reuse.
Results: :
Complete data on duration of lens use was present in 128 of 139 (92.0%) soft lens users. Among 19 of 51 (37.2%) AK cases and 21 of 77 (27.3%) controls who used lenses less for <=5 years, the odds ratio was not statistically significant (OR: 1.8; 95% CI: 0.7 - 4.5). Stratified ORs were also not significant and diverged: among subjects 13 - 18 years, 17 of 19 (89.5%) cases and 7 of 10 (70.0%) controls used lenses for <=5 years (OR: 8.1; 95% CI: 0.6 - 113.5); among subjects 19 - 74 years, 2 of 32 (6.3%) cases and 14 of 67 (20.9%) controls used lenses for <=5 years (OR: 0.2; 95% CI: 0.0 - 1.5).
Conclusions: :
No association exists between contact lens use <=5 years and AK, but contact lens initiation is not independent of age. Contact lens behaviors and hygiene anecdotally change with age. Our study, which further controls for confounding due to age-related behavior and hygiene changes through age-matched controls, suggests recent contact lens initiation is not a risk factor for AK.
Keywords: Acanthamoeba • clinical (human) or epidemiologic studies: risk factor assessment • cornea: clinical science