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November 1994

The Impact of Overnight Wear on the Risk of Contact Lens-Associated Ulcerative Keratitis-Reply

Author Affiliations

Baltimore, Md
Portland, Ore
Grand Rapids, Mich

Arch Ophthalmol. 1994;112(11):1405-1406. doi:10.1001/archopht.1994.01090230014004

In reply  The findings summarized in our report1 are not scientifically controversial. While epidemiologic research does not provide a conclusive causal linkage, such research approaches causality in these circumstances: (1) The effect or magnitude of the risk estimated is very large. The relative risks associated with overnight wear are of the same magnitude as those that have associated smoking with lung cancer. (2) The major findings are replicated in studies using different designs and in different locations. The magnitude and direction of our findings are remarkably similar to those of previous studies performed in the United States and England.2-4 (3) The findings are biologically plausible. With currently available contact lenses, the relative amount of corneal hypoxia that occurs with over-night wear has been well documented and the findings have been recently expanded and reconfirmed.5Nevertheless, despite the absence of "scientific controversy" about the principal findings of our

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