Single-piece AcrySof in the newborn rabbit eye

Abstract

Purpose: To evaluate the behavior of the single-piece AcrySof® SA30AT intraocular lens (IOL) (Alcon) in the eyes of newborn rabbits and to compare the postoperative complications in aphakic and pseudophakic eyes. Setting: St. Erik's Eye Hospital, Stockholm, Sweden. Methods: Clear lens extraction was performed in both eyes of 20 3-week-old rabbits. In 1 randomly selected eye in each rabbit, a single-piece acrylic IOL was implanted. Preoperatively and 1 and 2 months postoperatively, axial length and corneal diameter were measured. Corneal thickness was measured at the endpoint. The rabbits were also examined clinically; the position of the IOL and signs of secondary glaucoma were noted. At 2 months, the 19 surviving animals were killed. In 10 rabbits, the wet mass of the after-cataract was measured, and the eyes of 9 rabbits were fixed in formalin for histologic evaluation. Results: One animal died soon after surgery. Three rabbits developed secondary glaucoma in the aphakic eye. No rabbit developed glaucoma in the pseudophakic eye. In the 16 animals without secondary glaucoma, there were no significant differences in corneal diameter at 1 and 2 months or in corneal thickness at the endpoint; the axial length was significantly longer in aphakic eyes at 1 month, but not at 2 months. The aphakic eyes developed more posterior synechias and the pupil size at 1 and 2 months was significantly smaller in aphakic eyes than in pseudophakic eyes. Significantly more after-cataract developed in aphakic eyes than pseudophakic eyes (eyes with secondary glaucoma included). No difference in inflammation was seen between eyes in the histologic evaluation. In 11 of 19 pseudophakic eyes, the anterior capsulorhexis was not completely on the optic. In these eyes, the optic moved partly forward into the anterior chamber. Conclusion: The single-piece AcrySof SA30AT IOL seems to induce less inflammation and probably inhibits secondary glaucoma. It does not retard eye growth as much as previously tested IOLs. However, it is important to keep the entire capsulorhexis margin on the optic, especially in these small eyes.