Outcomes of ZB5M Angle-supported Anterior Chamber Phakic Intraocular Lenses at 12 Years
Journal of Refractive Surgery Vol. 23 No. 2 February 2007
Jaime Javaloy, MD, PhD; Jorge L. Alió, MD, PhD; Maria T. Iradier, MD; Ayman M. Abdelrahman, MD, MSc; Tomas Javaloy, MD; Fernando Borrás, MD, PhD
Quote:
For the IOL models analyzed in this study, a constant greater loss of endothelial cell density has been found. Considering a physiological rate of decrease in the endothelial cell density of 0.56% per year, a nonoperated healthy eye would reach age 85 years with >1900 cells/mm2. For these calculations, an amortization equation for accounting
has to be used:
(formula)
where ECDi is the current cell density estimated at any moment, ECD0 is the cell density at the fi rst considered instant, and n the number of years for calculating ECDi.
As we estimate a 10.69% surgically induced decrease in the endothelial cell density in the first year and an average rate of 1.78% every year after that, a hypothetical 25-year-old patient with an endothelial cell density of 2500 cells/mm2 who received a ZB5M angle-supported PIOL would reach the advisable explantation number of 1500 cells/mm2 at age 49 years (24 years after implantation). Later enhancements in the design of these angle-supported PIOLs may reduce long-term endothelial damage. The absence of a definitive physiopathological model of endothelial injury after angle-supported PIOL implantation and the large number of eyes implanted, especially in young patients, should oblige surgeons to perform periodic endothelial cell analysis in these patients.
