Efficacy of image-guided accurate limbal relaxing incisions for astigmatism correction during cataract surgery

Abstract

Purpose: To investigate the efficacy of image-guided accurate limbal relaxing incisions (LRIs) for astigmatism correction during cataract surgery.

Methods: Consecutive cataract patients with regular corneal astigmatism ranging from 0.75 to 2.50 D, intended for cataract surgery with image-guided LRIs, were recruited in this prospective cohort study. The efficacy of astigmatism correction was evaluated 3 months after surgery, and compared among eyes with preoperative corneal with-the-rule (WTR), against-the-rule (ATR) and oblique astigmatism. Higher-order aberrations and visual quality indices obtained with iTrace were further compared between eyes with single and paired LRIs.

Results: Totally, 108 eyes of 108 patients were analyzed. The mean total surgical induced astigmatism (tSIA) vector of all participants was 0.76 ​± ​0.38 D (range: 0.11-1.79 D, preoperative vs. postoperative astigmatism: 1.46 ​± ​0.41 vs. 0.78 ​± ​0.44 D, P ​< ​0.001). Eyes with WTR astigmatism showed higher tSIA (0.89 ​± ​0.32 D vs. 0.42 ​± ​0.21 D vs. 0.48 ​± ​0.36 D, respectively, P ​< ​0.001), as well as higher correction index and lower difference vector and index of success than ATR and oblique astigmatism groups (all P ​< ​0.05). Eyes with paired LRIs exhibited better corneal average height of modulation transfer function, a better corneal performance index and a better quality of vision index than those with single LRI (all P ​< ​0.05).

Conclusions: Image-guided LRIs can effectively correct low-to-moderate corneal astigmatism during cataract surgery, especially in eyes with WTR astigmatism.

Keywords: Astigmatism correction; Cataract surgery; Image-guided accurate limbal relaxing incisions; Visual quality.

Fig. 1

Examples of LRI online calculator and image-guided system. (A) An example of paired LRIs: Patient's keratometry and the main phacoemulsification laceration at 160° with an SIA of 0.5 D were inputted on the left. The recommended LRIs were shown in the middle, and the image-guided system used during surgery was exhibited on the right. The blue arc indicated the paired LRI-incisions and the main phacoemulsification incision. (B) An example of a single LRI. Patient's keratometry and the main phacoemulsification laceration at 160° with an SIA of 0.5D were inputted on the left. The recommended LRI was exhibited in the middle, and the image-guided system used during surgery was displayed on the right. The blue arc indicated the single LRI-laceration and main phacoemulsification incision.

Fig. 2

Double-angle plots of preoperative and postoperative corneal astigmatism of all participants at 3 months after surgery. Preoperative corneal astigmatism (left) and postoperative corneal astigmatism (right).

Fig. 3

Double-angle plots of preoperative and postoperative corneal astigmatism of eyes with WTR, ATR and oblique astigmatism at 3 months after surgery. (A) Preoperative corneal astigmatism (left) and postoperative corneal astigmatism (right) of eyes with WTR astigmatism. (B) Preoperative corneal astigmatism (left) and postoperative corneal astigmatism (right) of eyes with ATR astigmatism. (C) Preoperative corneal astigmatism (left) and postoperative corneal astigmatism (right) of eyes with oblique astigmatism. WTR, with-the-rule; ATR, against-the-rule.

Fig. 4

Comparison of higher-order aberrations (HOAs) of eyes with single and paired LRIs at 3 months after surgery. Corneal HOAs measured at pupil diameters of 6.0 ​mm and 4.0 ​mm ​(A) and ocular HOAs measured at pupil diameters of 6.0 ​mm and 4.0 ​mm ​(B). HOAs, higher-order aberrations; RMS, root mean square; LRI, limbal relaxing incision. Error bars represent the standard error of the mean.