The value of regular replacement of low water content contact lenses for extended wear.

Adverse effects were evaluated in 48 myopic patients who wore low water content hydrogel lenses for an average of 48 +/- 19 weeks. Only one acute "red eye" occurred in the regular replacement group (2% of patients), whereas seven cases (15%) occurred in the non-replacement lens wearing eye. The major cause of clinical failure was giant papillary conjunctivitis (GPC), but the incidence was similar in both the replaced (15%) and non-replaced (15%) lens wearing eyes. These findings indicate that the acute red eye incidence can be reduced by regular replacement, that unilateral lens replacement does not reduce the incidence of GPC and that regularly replacing low water content lenses does not minimize the chronic corneal changes that occur during extended wear.