Extended wear hydrogel lenses. Long-term effectiveness and costs.

During the period 1976-79, 1,201 of 1,552 aphakic patients were successfully fitted with third generation extended wear hydrogen lenses of thin-membrane design (CSI¿ lens) and highly hydrated polymer design (Permalens,¿Sauflon¿) without significant or permanent visula loss. Between 79% and 82% of the patients who failed did so in the first 90 days, and thereafter failure rates declined with time. Replacement rates for lenses approximated one lens per eye per year. Rates of required removal for cleaning varied. Ten to 13% of patients required cleaning at less than three-month intervals, and 5-6% at less than one month. For average patients with unilateral devices and no complication, extended wear lenses in Georgia are estimated to cost approximately three times as much as an intraocular lens over a 20-year follow-up period. General advantages ofextended wear third generation lenses include: (1) an acceptably savce and visually effective way to correct aphakia when patients are carefully selected, fitted, educated, and followed; (2) can be easily removeed, refitted or updated as technology advances; and (3) will not replace intraocular lenses, but can be used when implantation is contraindicated and should prevent the need for secondary or bilateral implantation or keratophakia in most cases.