Abstract
Purpose::
To assess the relative risks of acute, non-ulcerative complications with contemporary contact lens (CL) wear.
Methods::
A 2 year prospective case-control study commenced in December 2003. Cases were CL wearers attending as new patients to Moorfields Eye Hospital Accident and Emergency (A&E) with CL related-disorders other than microbial keratitis. There were two groups of controls: Hospital Controls (H-Cs) were CL wearers attending A&E as new patients with a disorder unrelated to CL wear, and Population-based Controls (POP-Cs) were CL wearers randomly selected from the A&E catchment area. Persons with a medical indication for CL wear were excluded. Hospital patients completed a self-administered questionnaire, while POP-Cs were interviewed by telephone.
Results::
There were 877 cases, 1,069 H-Cs and 639 POP-Cs. Compared to planned replacement soft hydrogel (PRS) CLs, daily disposable (DD) CLs significantly reduced the risk of toxic and hypersensitivity disorders, but were associated with a 2.0x (95% confidence limits 1.5-2.6, p<0.001) increased risk of mechanical disorders and a tendency for patients to have lens removal difficulties. Silicone hydrogel (SH) CL wear was free from hypoxic complications and not significantly different to PRS for the risk of sterile keratitis, papillary conjunctivitis or acute red eye, despite greater average frequency of overnight wear. SH lenses were associated with a significantly greater risk of mechanical disorders than PRS CL (1.9x, 1.1-3.4, p=0.029). The risks for any non-ulcerative complication was similar between CL types used for daily wear, while extended wear of any soft lens increased the risk by two to four times.
Conclusions::
Neither of the two newer CL modalities (DD and SH) reduced the overall risk of hospital-presenting non-ulcerative disorders. CL wearers should be fully instructed in lens handling, appropriate use of in-eye CL lubricants, and on the risk of complications with overnight CL use.
Keywords: contact lens • cornea: clinical science