ABSTRACT
OBJECTIVE: To assess the relative risk of contact lens-associated ulcerative keratitis by lens type and related lens-wearing behavior. DESIGN: Case-control study. SETTING/PARTICIPANTS: Forty practice-based case patients with contact lens-associated ulcerative keratitis and 180 control patients matched to the case patients' dispensing practitioner and date of contact lens prescription. RESULTS: Compared with users of daily-wear soft lenses, users of disposable soft contact lenses had a 13.33-fold (95% confidence interval [CI], 5.35 to 33.20) excess risk of ulcerative keratitis. However, after adjusting for overnight wear, the excess risk associated with disposable contact lenses is reduced to 3.21 (95% CI, 1.22 to 14.36). Overall, overnight wear of contact lenses conferred an 8.25-fold excess risk (95% CI, 3.33 to 25.58) of ulcerative keratitis after controlling for lens type. No protective effect of standard compared with substandard lens hygiene was found. The risk of ulcerative keratitis attributable to overnight wear was estimated at 49% for users of daily-wear lenses and 74% for users of lenses approved for overnight wear. CONCLUSION: Overnight wear of contact lenses is the overwhelming risk factor for ulcerative keratitis among contact lens users. We estimate that 49% to 74% of cases of contact lens-associated ulcerative keratitis could be prevented by eliminating overnight wear.
Subject(s)
Contact Lenses, Hydrophilic/adverse effects , Corneal Ulcer/etiology , Adolescent , Adult , Case-Control Studies , Confidence Intervals , Disinfection/methods , Disposable Equipment , Female , Health Behavior , Humans , Male , Middle Aged , Odds Ratio , Risk FactorsABSTRACT
PURPOSE: Pseudophakic corneal edema is the principal indication for penetrating keratoplasty in the United States. Currently, three techniques of intraocular lens (IOL) fixation during penetrating keratoplasty for this condition are commonly used--flexible anterior chamber IOL (AC IOL) implantation, iris suture fixation of a posterior chamber IOL (PC IOL), and transscleral suture fixation of a PC IOL. This study represents the first prospective, randomized comparison of these three techniques. METHODS: One hundred seventy-six consecutive patients with pseudophakic corneal edema who underwent penetrating keratoplasty with IOL exchange were randomized to one of the three implantation techniques. Standardized evaluations were performed at baseline and at 6, 12, and 18 months postoperatively. Life-table analysis provided cumulative risk estimates for specific complications. RESULTS: Randomization produced comparable groups at baseline. The cumulative risk of macular edema was significantly less for the iris fixation cohort than for either the AC IOL or scleral fixation group. A complications index was constructed based on the major adverse outcomes of glaucoma escalation, cystoid macular edema, IOL dislocation, and graft failure. A significantly lower risk of complication was found for iris compared with scleral fixation of PC IOLs. CONCLUSION: The authors conclude that transscleral fixation of the PC IOL at the time of penetrating keratoplasty for pseudophakic corneal edema is associated with a greater risk of adverse outcome than iris fixation of a PC IOL.
Subject(s)
Corneal Edema/surgery , Keratoplasty, Penetrating , Lenses, Intraocular/adverse effects , Suture Techniques/adverse effects , Aged , Anterior Chamber/surgery , Cataract Extraction , Female , Humans , Iris/surgery , Life Tables , Male , Postoperative Complications , Prospective Studies , Risk Factors , Sclera/surgeryABSTRACT
Previous controlled studies on contact lens-associated ulcerative keratitis were performed before the widespread use of disposable contact lenses. Therefore, a controlled study was undertaken to determine the relative risk of ulcerative keratitis among users of disposable soft contact lenses compared with the risk among users of other lens types. Forty-six consecutive cases of contact lens-associated ulcerative keratitis were identified between January 1990 and June 1992 at a corneal specialty practice in western Michigan. Five controls, matched to each case patient according to the dispensing data and prescribing practitioner, were obtained for 42 cases (91%). Users of daily-wear rigid gas-permeable lenses had the lowest risk of developing ulcerative keratitis. Relative to users of daily-wear soft contact lenses, users of extended-wear soft contact lens had an age-adjusted and sex-adjusted relative risk of 1.87 (95% confidence interval, 0.61 to 5.71). Disposable soft contact lens users had the highest risk of developing ulcerative keratitis, with an adjusted relative risk of 14.16 (95% confidence interval, 5.47 to 37.63) compared with daily-wear soft contact lens users and 7.66 (95% confidence interval, 2.27 to 25.83) compared with conventional extended-wear soft contact lens users.
Subject(s)
Contact Lenses, Hydrophilic/adverse effects , Corneal Ulcer/etiology , Disposable Equipment , Acanthamoeba Keratitis , Adolescent , Adult , Case-Control Studies , Child , Corneal Ulcer/parasitology , Female , Humans , Male , Middle Aged , Prospective Studies , Retrospective Studies , Risk FactorsABSTRACT
Two patients developed Acanthamoeba keratitis associated with the use of disposable extended-wear hydrogel contact lenses. Both patients removed, irrigated, and reinserted the contact lenses without disinfecting them. One patient wore the lenses on a daily basis, rinsed the lenses in tap water, stored them overnight, and discarded them weekly. Both infections were treated successfully. In a third patient, Acanthamoeba species was cultured from two pairs of disposable lenses that had been stored in cases rinsed with well water. Potential benefits from disposable contact lens wear are negated when patients do not comply with a continuous wearing schedule.
