Purchase this article with an account.
JC Merriam, L Zheng, J Urbanowicz, J Dillon; The Relation of Pre-operative Corneal Astigmatism to Surgically-induced Astigmatism After Cataract Surgery . Invest. Ophthalmol. Vis. Sci. 2002;43(13):396.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Purpose:To evaluate the long-term effect of preoperative corneal astigmatism on surgically-induced astigmatism (SIA) following 4 different incisions: extracapsular cataract extraction with a 12 mm incision (ECCE), 6 mm superior scleral tunnel (6Sup), 3 mm superior scleral tunnel (3Sup), and 3 mm temporal scleral tunnel (3Temp). Methods:This retrospective study includes 420 eyes with either preoperative "with the rule" or "against the rule" astigmatism: 143 ECCE, 75 6Sup, 122 3Sup, and 80 3Temp. There were too few eyes with no or oblique corneal astigmatism for long-term analysis. Eyes that developed an inadvertent filtering bleb or had combined glaucoma and cataract surgery also were excluded. Each group was divided into eyes with preoperative WTR and ATR astigmatism, and SIA for each subgroup was calculated with 5 different methods: Jaffe's vector analysis, Naeser's polar coordinates, and three axis-based methods (Cravy's (both Kd and Kt) and a simplified axis-based technique). Mean SIA for each subgroup was compared with the t-test at discrete postoperative intervals for 5 years after ECCE, 6Sup, and 3Sup, and 4 years after 3Temp. Results:After each incision, SIA in eyes with preoperative WTR or ATR astigmatism was indistinguishable, using any of the methods for calculating SIA, at a significance level of 0.01. Conclusion:Preoperative corneal astigmatism does not have a measurable effect on SIA following 4 standard incisions for cataract.
This PDF is available to Subscribers Only