Cf. Radford et al., DISPOSABLE CONTACT-LENS USE AS A RISK FACTOR FOR MICROBIAL KERATITIS, British journal of ophthalmology, 82(11), 1998, pp. 1272-1275
Aims-A case-control study was performed to evaluate soft contact lens
(SCL) wear modality as a risk factor for microbial keratitis. Methods-
Contact lens wearers presenting as new patients to Moorfields Eye Hosp
ital accident and emergency department during a 12 month period comple
ted a self administered questionnaire detailing demographic data and c
ontact lens use habits. Cases were patients with a clinical diagnosis
of SCL related microbial keratitis. Controls were SCL users attending
with disorders unrelated to contact lens wear. Odds ratios (estimates
of relative risks) and 95% confidence Limits (CL) were calculated thro
ugh multivariable logistic regression analysis. Results-There were 89
cases and 566 controls. A substantially increased risk with 1-4 weekly
disposable SCL compared with non-disposable SCL was identified among
both daily wear (DW) (odds ratio =3.51, 95% CL 1.60-7.66, p=0.002) and
extended wear (odds ratio 4.76, 95% CL 1.52-14.87, p=0.007) users aft
er adjustment for demographic, lens use and hygiene variables. Other s
ignificant factors among DW users were ''occasional'' overnight use, u
se of chlorine based (as opposed to other chemical) systems in combina
tion with poor storage case hygiene, and irregular disinfection. Concl
usion-Properties of some disposable SCL may be partly responsible for
these excess risks. It is also possible, however, that this finding is
largely a reflection of widespread complacency among patients and pra
ctitioners with respect to disposable SCL fitting and use.