Adverse events with silicone hydrogel continuous wear.
High Dk silicone hydrogel lenses have overcome many of the hypoxic problems associated with traditional extended wear and the popularity of continuous wear (up to 30 nights) with these lens types is increasing. Results from clinical trials indicate that the typical physiological changes associated with edema from conventional extended wear of low Dk/t lenses do not occur with continuous wear of silicone hydrogel lenses. These changes include neovascularization, striae, microcysts and an increase in bulbar and limbal hyperemia. It is perhaps not surprising though that a number of adverse events do still occur with silicone hydrogel lenses when they are worn on a continuous wear basis. These include inflammatory conditions such as contact lens-induced peripheral ulcers (CLPU), contact lens-induced acute red eye (CLARE), infiltrative keratitis (IK) and contact lens papillary conjunctivitis (CLPC). Other events such as superior epithelial arcuate lesions (SEAL) and localised CLPC may be due to mechanical influences. While these conditions are not sight threatening, they may be painful and are certainly inconvenient to both the patient and the practitioner. It is therefore very important that the signs and symptoms associated with these events be recognised in order that they may be accurately identified and appropriately managed. The purpose of this review article is to describe the pathophysiology, etiology, and clinical presentation of these adverse events when observed with continuous wear contact lenses and to discuss their associated risk factors and incidence. Clear management and treatment strategies are also presented and a number of approaches to minimize adverse events with continuous wear of silicone hydrogel contact lenses are suggested.
Dumbleton
Kathy
K
Centre for Contact Lens Research, School of Optometry, University of Waterloo, Waterloo, Ont., Canada. kdumble@scimail.uwaterloo.ca