DEC 20, 2011
This prospective study published as a correspondence in November in the Journal of Cataract & Refractive Surgery reports on the effect and stability of limbal relaxing incisions (LRIs) at reducing pre-existing astigmatism at the time of phacoemulsification. The authors found that this treatment significantly reduced preoperative astigmatism in patients who underwent the procedure unilaterally, with no regression noted after a follow-up of six months. While most ophthalmologists feel that astigmatism regresses after this treatment, I agree with this paper.
This is one of the largest series reported to date for the correction of pre-existing astigmatism using LRIs. Subjects were 200 patients with pre-existing keratometric astigmatism of 1.0 D or higher. LRIs were made at the most peripheral extent of the clear cornea, just inside the true surgical limbus, after achieving good globe fixation. Phacoemulsification was then performed through an astigmatically neutral temporal incision, and a foldable IOL (Acrysof SA60AT, Alcon Laboratories, Inc.) was implanted in the capsular bag.
The authors found that the LRI-induced astigmatic correction stabilized early and remained stable during the six months of postoperative follow-up. Most complications were mild and clinically nonsignificant.
The mean preoperative astigmatism was 1.58 ± 0.55 D, compared with a mean postoperative astigmatism of 0.50 ± 0.29 D at one week (P < 0.001) and 0.44 ± 0.25 D at six months (P < 0.001). Six months after surgery, UDVA was 6/12 or better in 94.5 percent of eyes, and CDVA reached the same level in 99.5 percent of eyes. Both were significant improvements compared with preoperative levels (P = 0.0000 for both). Four patients (2 percent) experienced intraoperative extensions of the LRIs and 21 (10.5 percent) reported immediate postoperative foreign-body sensation.
The authors conclude that although toric IOLs are increasingly used to manage pre-existing astigmatism, LRIs remain a potentially useful, economical and effective option.