Purpose: To evaluate the effects of an intraocular lens (IOL) designed for small eyes after clear lens extraction in an animal model.
Setting: St. Erik's Eye Hospital, Karolinska Institute, Stockholm, Sweden.
Methods: Clear lens extraction was performed in both eyes in 19 3-week-old rabbits. In 1 randomly selected eye of each rabbit, a small IOL with long haptics was implanted. Axial length, corneal thickness, corneal diameter, and intraocular pressure were measured preoperatively and every month for 6 months postoperatively. Six months after surgery, the wet mass of the after-cataract was determined.
Results: The IOL remained well centered in all eyes. Four animals developed severe glaucoma in 5 eyes (3 aphakic and 2 pseudophakic) soon after surgery and were excluded. In the 15 animals completing the study, signs of glaucoma evolved in 7 animals (5 aphakic and 4 pseudophakic eyes). In aphakic eyes, significant amounts of after-cataract (median 250 mg) developed in all 15 surviving animals. In pseudophakic eyes, small amounts of after-cataract (median 30 mg) were present. During the first 2 months after surgery, ocular growth was less in pseudophakic eyes than in aphakic eyes.
Conclusions: Results indicate that implantation of a down-sized IOL with long haptics in small eyes is safe. Considerable less after-cataract was found in eyes with the IOL than in aphakic control eyes.