limbal relaxing incision to correct pre-existing corneal astigmatism in patients undergoing phacoemulsification

purpose: to evaluate the effectiveness of limbal relaxing incision (lri) during phacoemulsification for correcting pre-existing corneal astigmatism. methods: the study included 21 eyes of 21 patients undergoing phacoemulsification combined with lri and 36 eyes of 36 patients undergoing phacoemulsification without lri as controls. lri was created according to a nomorgram based on preoperative astigmatism as determined by topography. jaffe vector analysis was used for evaluation of changes in astigmatism. results: mean corneal astigmatism was 2.82±1.07 diopter (d) preoperatively which decreased to 1.68±1.03 d 12 weeks postoperatively in the lri group. corresponding figures were 0.66±0.27 d and 0.62±0.22 d in controls respectively. mean arithmetic reduction in keratometric astigmatism was 1.19±1.04 d and mean vector change in cylinder was 2.37±1.36 d in the lri group. thirteen cases (61.9%) of under-correction and two cases (9.5%) of over-correction occurred in the lri group. conclusion: limbal relaxing incision is effective in reducing pre-existing corneal astigmatism during cataract surgery; however a modified nomogram is needed.