Elsevier

Ophthalmology

Volume 115, Issue 10, October 2008, Pages 1647-1654.e3
Ophthalmology

Original article
Risk Factors for Microbial Keratitis with Contemporary Contact Lenses: A Case-Control Study

https://doi.org/10.1016/j.ophtha.2008.05.003Get rights and content

Objective

To assess the relative risks (RR) of microbial keratitis (MK) for contemporary contact lens (CL) types and wearing schedules.

Design

A 2-year prospective case-control study begun in December 2003.

Participants

Cases were 367 CL wearers attending Moorfields Eye Hospital with proven or presumed MK. Controls were 1069 hospital controls, who were CL wearers with a disorder unrelated to CL wear, and 639 population-based controls who were CL wearers randomly selected from the Moorfields catchment area. Hospital patients completed a self-administered questionnaire; population-based controls were interviewed by telephone.

Testing

Multivariate analysis was done both for all cases of MK, and for the moderate and severe MK subgroups alone.

Main Outcome Measures

The RR for developing MK, and vision loss, for all lens types compared with planned replacement soft lenses (the referent).

Results

Compared with planned replacement soft lenses (the referent), the RR of MK was significantly increased with daily disposable (DD) CLs (RR, 1.56× [95% confidence interval (CI), 1.1–2.1]; P = 0.009) and differed between different brands of DD lens, was reduced for rigid lenses (RR, 0.16× [95% CI, 0.06–0.4]; P<0.001), and no different for silicone hydrogel or other types of soft lens. Although the risk of MK was higher overall among DD lens users, the risk of vision loss was less than for planned replacement soft CL users (P = 0.05); no DD lens users lost vision to the level of ≥20/40. The RR for overnight wear, for any lens type, was 5.4 times higher (95% CI, 3.3–10.9; P<0.001). Comparison of the DD soft CL types with planned replacement soft lenses (the referent), showed significant differences between brands for the risk of MK.

Conclusions

The risk of MK has not been reduced in users of DD and silicone hydrogel CLs. However, vision loss is less likely to occur in DD than in reusable soft CL users. Different brands of CL may be associated with significantly different risks of keratitis; understanding these differences should lead to the development of safer soft lenses. These findings suggest that lens/ocular surface interactions may be more important in the development of corneal infection than oxygen levels and CL case contamination.

Financial Disclosure(s)

The authors have no proprietary or commercial interest in any materials discussed in this article.

Section snippets

Methods

This was a prospective case-control study with data collection during the 2-year period beginning December 3, 2003.

Results

The study design resulted in 367 cases and 2075 controls from 185 of 220 (84%) of Greater London postcodes (population of Greater London30 7 172 000) as well as from 241 UK postal districts outside London.

Table 3 shows the demographic data and the distribution of lens types and wear schedules for the 367 MK cases and the 2 different control groups included in the study. Another 241 CL users had corneal infiltrative events29 and were not included in this study. There were 77 hospital cases and

Discussion

This study measured the risks of MK, for the first time, for the DD soft CLs and silicone hydrogel lenses that have been introduced in the 10 years since the completion of the previously published epidemiologic studies on MK in CL wearers.1, 3, 4 The design of this study has provided the largest MK case series to date and a sample of patients from a large catchment area, which allows extrapolation of our findings to CL users in the United Kingdom and other similar environments. A limitation of

Acknowledgments

The authors thank the following steering committee members—O. Schein, D. Cavanagh, B. Holden, H. Taylor, D. Fonn, and J. McNally—for protocol and data review, and Dr Eric Beck, Ms Valerie Saw, and Ms Alison Mathews for reviewing the manuscript.

The authors were responsible for the design and conduct of the study; had access to and carried out the collection, management, analysis, and interpretation of all the data; and then undertook the preparation, review, and approval of the manuscript. A

References (35)

  • F. Stapleton et al.

    Epidemiology of Pseudomonas aeruginosa keratitis in contact lens wearers

    Epidemiol Infect

    (1995)
  • H. Hamano et al.

    A study of the complications induced by conventional and disposable contact lenses

    CLAO J

    (1994)
  • O.D. Solomon et al.

    A 3-year prospective study of the clinical performance of daily disposable contact lenses compared with frequent replacement and conventional daily wear contact lenses

    CLAO J

    (1996)
  • R.L. Chalmers et al.

    Impact of previous extended and daily wear schedules on signs and symptoms with high Dk lotrafilcon A lenses

    Optom Vis Sci

    (2005)
  • C. Riley et al.

    Prevalence of ocular surface symptoms, signs, and uncomfortable hours of wear in contact lens wearers: the effect of refitting with daily-wear silicone hydrogel lenses (Senofilcon A)

    Eye Contact Lens

    (2006)
  • M. Hingorani et al.

    Ulcerative keratitis in a person wearing daily disposable contact lenses [letter]

    Arch Ophthalmol

    (1995)
  • S.A. Woodruff et al.

    Acanthamoeba keratitis occurring with daily disposable contact lens wear [letter]

    Br J Ophthalmol

    (1999)
  • Cited by (299)

    • Extended Wear

      2023, Contact Lens Practice, Fourth Edition
    • History Taking

      2023, Contact Lens Practice, Fourth Edition
    • Daily Disposable Lenses

      2023, Contact Lens Practice, Fourth Edition
    View all citing articles on Scopus

    Manuscript no.: 2007-1401.

    Financial Disclosure(s): None of the authors have any personal conflicts of interest.

    Supported by the Institute for Eye Research, University of New South Wales, Sydney, Australia from a project grant made by CIBA Vision Corporation.

    View full text