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Amilia Schrier, Elona Gavazi, Jessica Kerns, Stanley Chang; Comparison of Predicted Refractions to Outcome Refractions in Patients Undergoing Combined Macula Surgery and Phacoemulsification Versus Patients Undergoing Phacoemulsification Alone. Invest. Ophthalmol. Vis. Sci. 2012;53(14):6714.
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To determine if intraocular lens (IOL) calculations are reliable in combined phacoemusification and macula surgeries.
A retrospective chart review was done to evaluate the difference between the predicted and outcome refractions in two different groups: A control group of 81 eyes in patients with phacoemulsification alone and 104 eyes in patients with combined phacoemulsification and macula surgeries from 2004-2011. Predicted and outcome refractions were converted to spherical equivalents, rounded to the nearest quarter diopter. The differences were calculated and the data was analyzed to obtain the mean change in both groups and the confidence interval for the difference between means, for the purpose of assessing equivalence. Acceptable refractive outcomes were predetermined to be within +/- 0.50 diopters of predicted refraction. All surgeries were performed by a single cataract surgeon and a single retina surgeon. The study was approved by Columbia University Medical Center Institutional Review Board and HIPPA Privacy Office.
The mean difference in predicted versus outcome refraction in the phacoemulsification group was 0.09 with a standard deviation of 0.66, range (-1.5, 1.75). The mean difference in predicted versus outcome refractions in the combined macula and phacoemulsification group is -0.12 with a standard deviation of 0.71, range (-2, 2.63). To assess equivalence, we defined an equivalence region, where differences between groups are close enough that they would be judged to be not clinically meaningful. Then, when calculating a confidence interval for the difference in means between the two groups, our interval fell entirely within this equivalence region. Acceptable refractive outcomes were determined to be within +/- 0.50 diopters of predicted refraction. The confidence interval or the difference in mean change for the two groups is 0.2 [ 0.09 - (-0.12)]. The confidence interval for this is (0.01, 0.4) .
Combined phacoemulsification and macula surgery yields reliable and predictable refractive results. This may suggest a safe, tolerable, and economical treatment strategy for patients in need of macula surgery.
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