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Peripheral corneal relaxing incisions combined with cataract surgery
L i Wang1, Manjula Misra, Douglas D Koch
1Cullen Eye Institute, Baylor College of Medicine, Houston, Texas 77030, USA.
Purpose:
To analyze the effectiveness of peripheral corneal relaxing incisions (PCRIs) in correcting corneal astigmatism during cataract surgery.
Setting:
Cullen Eye Institute, Baylor College of Medicine, Houston, Texas, USA.
Methods:
In 115 eyes of 94 patients (mean age 69 years +/- 12 [SD]), cataract surgery was combined with PCRIs. The PCRIs were created according to a nomogram based on age and preoperative keratometric astigmatism. Postoperative keratometric astigmatism was measured at 1 day and 1 and 4 months. Vector analyses using the Holladay-Cravy-Koch formula and Alpins method were performed.
Results:
The PCRIs significantly decreased keratometric astigmatism in patients with preexisting with-the rule (WTR) or against-the-rule (ATR) astigmatism and increased the percentage of the eyes with lower keratometric astigmatism in each group. Four months postoperatively in patients with WTR astigmatism, single and paired 6.0 mm PCRIs induced mean with-the-wound minus against-the-wound changes (WTW-ATW) of -0.55 diopter (D) and -1.18 D, respectively. In eyes with ATR astigmatism, the mean WTW-ATW changes induced by single 4.5 mm, single 6.0 mm, and paired 6.0 mm PCRIs were -2.18 D, -2.02 D, and -2.72 D, respectively. These mean WTW-ATW changes did not significantly regress from 1 day to 4 months postoperatively.
Conclusions:
Peripheral corneal relaxing incisions were effective in reducing preexisting astigmatism during cataract surgery. A modified nomogram is proposed. The long-term effect of PCRIs should be evaluated.