Endothelial cell loss after toric iris-fixated phakic intraocular lens implantation: three-year follow-up

To study quantitative changes in endothelial cell count after implantation of the toric iris-fixated phakic intraocular lens.

A prospective, non-randomized, self-controlled clinical trial was conducted of 40 eyes (28 myopic, 12 hyperopic) of 23 patients with high ametropia and astigmatism. Non-contact computer-assisted endothelial microscopy was performed before and 1, 2, and 3 years after surgery.

In the myopic group, mean preoperative endothelial cell count was 3179 +/- 531 cells/mm2 (range: 1800 to 3900 cells/mm2). The mean intra-individual endothelial cell loss was -1.83 +/- 2.25% (range: -9.09% to 0%) in the first year; -1.83 +/- 2.95% (range: -7.74% to 3.80%) in the second year; and -3.20 +/- 4.43% (range: -14.25% to 1.91%) three years after surgery, compared to preoperative values. In the hyperopic group, mean preoperative endothelial cell count was 3107 +/- 125 cells/mm2 (range: 2932 to 3300 cells/mm2). The mean endothelial cell loss was -1.63 +/- 1.76% (range: -3.23% to 1.67%) in the first year; -0.05 +/- 1.25% (range: -1.65% to 1.75%) in the second year; and -2.88 +/- 2.03% (range: -5.33% to -0.13%) three years after surgery, compared to preoperative values.

Annual cumulative cell loss was -1.9% for the myopic group and -1.6% for the hyperopic group, which is two to three times greater than physiological annual cell loss in normal eyes without surgery. An annual endothelial cell count analysis is highly recommended in every patient after iris-claw lens implantation to detect potential progressive cell loss at an early stage.