Implantation of a toric IOL appears to be a safe and effective method for correcting spherical error and astigmatism in eyes with cataract and a history of penetrating keratoplasty.
New York-Implantation of a toric IOL appears to be a safe and effective method for correcting spherical error (SE) and astigmatism in eyes with cataract and a history of penetrating keratoplasty (PKP), said Renée Solomon, MD, a private practitioner in New York.
Dr. Solomon presented outcomes from a prospective study of 10 post-PKP eyes of eight patients in whom a toric IOL had been implanted after surgery for a visually significant cataract. Inclusion criteria required that the eyes have refractive cylinder between 1 and 5 D at the time of cataract surgery and have had the graft sutures removed at least 3 months earlier. For standardization, one surgeon, Eric Donnenfeld MD, performed all cataract surgeries.
All eyes experienced improvements in uncorrected visual acuity (UCVA), best-corrected (BCVA), and cylinder, and statistically significant improvements were observed in the mean values for all three parameters. Mean refractive cylinder was reduced from 3.37 D preoperatively to 1.59 D postoperatively.
Of the 10 eyes included in the series she presented, six were implanted with one proprietary toric IOL (STAAR Toric, STAAR Surgical), and four received another proprietary toric IOL (AcrySof Toric, Alcon Laboratories). Mean preoperative UCVA was 20/300 with a range from 20/80 to count fingers, and it improved to a mean of 20/40. Mean BCVA improved from 20/70 to 20/25. Mean preoperative SE was 2.62 D and was reduced to –0.67 D.
New options important
Identifying new options to manage astigmatism after PKP is an important issue considering that more than 40,000 PKP procedures are performed annually and that astigmatism, along with anisometropia, can limit visual rehabilitation, Dr. Solomon said.
"Mean cylinder after the transplant procedure is about 4 to 5 D, and existing management techniques have limitations in correcting post-PKP cylinder," she said. "Contact lenses can be used, but many patients are contact-lens intolerant. Corneal relaxing or limbal incisions are an option, but often the amount of astigmatism present is greater than can be managed with these techniques. The excimer laser has also been used, but there are concerns with performing both LASIK and PRK in post-PKP eyes."