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  • Title: What have pre- and postapproval studies shown about contact lens-related inflammatory events?
    Author: Chalmers RL.
    Journal: Eye Contact Lens; 2007 Nov; 33(6 Pt 2):388-91; discussion 399-400. PubMed ID: 17975428.
    Abstract:
    INTRODUCTION: Clinical studies that occur before and after the regulatory approval of contact lenses differ in many aspects, including breadth, length, and subject inclusion and exclusion criteria. METHODS: A sample of published studies conducted in North America was reviewed to outline these differences and show their impact on rates of corneal complications with lenses. RESULTS: In postapproval studies of silicone hydrogel lenses, subject age and refractive error have been more diverse than in pre-approval trials, for example, 42% of lens wearers in a postapproval study of a single vision contact lens being older than 40 years. Inclusion of subjects in a wider age range in that study showed that lens wearers older than 50 years were at an increased risk for corneal infiltrates. Few adolescents were included in the first pre-approval trials of tisilfocon A overnight orthokeratology lenses, although many teenagers are prescribed the lenses in practice and may be at a higher risk for corneal infections with the device. The range of spectacle refractive error in a large postapproval registry of lotrafilcon A patients ranged from -16.00 to +7.00 diopters, significantly greater than that in pre-approval studies. A nonrandomized postapproval study showed that patient selection resulted in older patients with a higher degree of ametropia receiving silicone hydrogel lenses compared to younger patients with lower ametropia being fitted with hydrogel lenses. CONCLUSIONS: Postapproval studies give an organized view of the type of patients who will eventually make up the wearing population and their success or limitations with new types of contact lenses.
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