Five-year Follow-up of a Prospective Study Comparing Hydrogel with PMMA Single Piece Lenses

Abstract

OBJECTIVE: To compare the long-term clinical performance of a hydrogel lens with a standard PMMA intraocular lens after complication-free surgery. STUDY DESIGN: Prospective trial of 125 cases of hydrogel lenses and 125 PMMA lenses matched exactly for age and sex, implanted over the same time scale, by the same methods with a minimum follow-up of 5 years. Protocol excluded cases with pre-implantation operative complications, uncertainty of bag placement at surgery and other ocular pathology. SETTING: District General Hospital, UK. MAIN OUTCOME MEASURES: Visual acuity and lens position at 5 years, lens-related complications, incidence of macular disease, incidence of posterior capsulotomy. RESULTS: At 5 years in each group 97% were seeing 6/12 or better and 61% were seeing 6/6 or better. Implant precipitates were significantly more common on PMMA lenses ( P = 0.002). ‘C’ deformity occurred in 3.2% of hydrogel lenses and dislocation into the vitreous in two cases. Subclinical decentration was more common in PMMA lenses. The total incidence of laser capsulotomy was 29.6% for hydrogel lenses and 41.6% for PMMA lenses. The incidence of macular disease was similar in each group despite the absence of UV blocking chromophores in the hydrogel lenses. CONCLUSIONS: Although the 1986 hydrogel design (Iogel® PC12) is now obsolete, the material has withstood the test of time in being eminently suitable for bag implantation and this has important implications for small incision surgery.