Abstract
To retrospectively examine PMMA intraocular lenses with glistenings for the grade of glistenings, the time from implantation to development of glistenings, and effect on visual function. Approximately, 14, 000 PMMA lenses were implanted in our hospital from January 1979 to December 1992. This study examined 163 eyes in 127 of the patients who had received an implanted lens over the period from May 2001 to March 2002. In 15 eyes that showed glistenings (13 patients), we studied various factors related to glistenings. Contrast sensitivity was measured using CSV-1000E (Vector Vision), with and without glare, in 7 eyes of 6 patients with PMMA lenses implanted in the posterior chamber who were able to visit our hospital. Glistenings developed in PMMA lenses, whether manufactured by lathe cutting or by injection molding, some of which contained a UV absorber. Glistenings developed later on average (5.9 years after implantation in the earliest case) in more PMMA lenses than in acrylic lenses. The glistenings were graded as follows : glistenings with 50 bright spots per 1 mm3 were graded as G1; those with 100 spots per 1 mm3 as G2, and those with 200 per 1 mm3 as G3. Among the 7 eyes evaluated there were 5, 1 and 1 lens with G 1, G2 and G3 glistenings, respectively. All eyes examined showed reduced contrast sensitivity under conditions of glare. Glistenings developed in PMMA lenses 6 or more years after they were implanted. There was no statistical difference in the appearance of the glistenings between lenses manufactured by injection molding compared with those manufactured by lathe cutting (P=0.413, 2×2 Chi square test), nor were the manufacturing methods related to the grade of glistenings (P=0.407, Mann-Whitney U-test) . Glistenings in PMMA lenses do not affect visual acuity or contrast sensitivity, but may reduce contrast sensitivity at low, middle and high frequency ranges when exposed to glare.
