Objective: To determine the type and incidence of adverse events seen in the first 13 months of extended wear from a prospective clinical trial involving the use of disposable hydrogels on a 6-night extended wear and replacement schedule.
Design: A prospective, noncomparative clinical trial.
Participants: Three hundred thirty subjects were enrolled in the study from March 1993 to August 1996 and commenced in extended wear. The subjects were new contact lens users with ages ranging from 16 to 39 years and refractive errors from -1.00 to -6.50-diopter (D) sphere with cylindrical component less than 1.0 D.
Intervention: Disposable hydrogel lenses on a 6-night extended wear and replacement schedule.
Main outcome measures: To determine the incidence of adverse events in the first 13 months of lens wear with the use of disposable hydrogels on an extended wear schedule. In addition, corneal infiltrative events observed with lens wear were classified based on their presenting signs and symptoms.
Results: A total of 137 adverse events were seen in 102 subjects in the first 13 months of extended wear. The type of adverse events and the incidence per 100 patients per year of lens wear were as follows: corneal infiltrative events (44.4 events), contact lens papillary conjunctivitis (6.4 events), neovascularization and corneal wrinkling (1.7 events each), corneal striae and superior epithelial arcuate lesions (1.3 events each), and blepharokeratoconjunctivitis (0.4 event). Viral keratoconjunctivitis was also observed (0.8 event). The corneal infiltrative events were further subclassified as follows: contact lens-induced peripheral ulcers (13.6 events), contact lens-induced acute red eyes (12.3 events), infiltrative keratitis (9.7 events), and asymptomatic infiltrative events (8.9 events). There were no events of infectious keratitis. Except for all events of contact lens-induced peripheral ulcers and two isolated events of infiltrative keratitis that resulted in scarring, all of the corneal infiltrative events resolved without sequelae. None of the events caused any loss of best-corrected visual acuity.
Conclusions: Based on the observations from the first 13 months of extended wear in the trial, the majority of the complications associated with extended wear of disposable hydrogels are corneal infiltrative events. No events of microbial keratitis were seen in the first 13 months of extended wear. None of the events were associated with loss in best-corrected visual acuity. Clearly, frequent and regular disposing of lenses does not eliminate adverse effects, and better materials and designs are required for extended wear to be a successful method.