Objective: To evaluate the type and incidence of adverse events seen with daily disposable hydrogel contact lens wear compared with a control (spectacle) group over 12 months.
Design: Prospective, randomized, observer-masked, comparative clinical trial.
Participants: Two hundred eighty-one myopes with no prior contact lens wear experience were enrolled from August to December 1996. Subjects were 16 to 35 years old and had refractive errors ranging from a -0.75-diopter (D) sphere to a -6.00-D sphere with a cylinder less than -1.00 D.
Intervention: Each subject was randomly assigned to wear either bilateral disposable hydrogels on a daily disposable wear schedule or spectacles.
Main outcome measure: Type and incidence of adverse events from each group. Adverse events were categorized as serious, significant, and nonsignificant based on the potential to cause vision impairment, severity at event, and level of clinical concern.
Results: At baseline, 1.6% of eyes had asymptomatic infiltrates that were nonsignificant. During the study, asymptomatic infiltrates were seen in both contact lens and spectacle groups at 20.5 events versus 11.3 events per 100 eyes per year of wear. No significant events were seen with the spectacle group. With the contact lens group, the type and incidence of significant events per 100 eyes per year of lens wear were corneal peripheral ulcer, 2.5 events; infiltrative keratitis, 1.5 events; and papillary conjunctivitis, 1 event. The incidence of both significant and nonsignificant events was greater with the contact lens group (P<0.05). No serious events (i.e., microbial keratitis) were seen in either group. A greater number of subjects were lost to follow-up or permanently discontinued from the contact lens group relative to the spectacle group (33% vs. 17%, P = 0.002). Lens-related problems such as dryness, discomfort, and difficulty with insertion and removal accounted for 27% of discontinuations from the contact lens group. Poor compliance (40%) was the greatest reason for discontinuations from the spectacle group.
Conclusions: No clinically serious events were seen with either group. Only a small percentage of contact lens-wearing eyes presented with significant events, which is promising for daily disposable lens wear. Far more contact lens subjects were lost to follow-up or discontinued. Small, asymptomatic, subepithelial corneal infiltrates of unknown significance were seen in both contact lens- and spectacle-wearing eyes.