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B. Samy, Z. Ferrufino, B.A. Henderson, S.L. Cremers; Effect of Wound Location on Surgically Induced Astigmatism in Resident Cataract Surgery . Invest. Ophthalmol. Vis. Sci. 2005;46(13):782.
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© ARVO (1962-2015); The Authors (2016-present)
Purpose: To determine the correlation between wound location and surgically induced astigmatism in resident cataract surgery. Methods: Medical records of all cataract extractions performed by or under the supervision of two Harvard Medical School ophthalmology surgical preceptors from July 2003 to July 2004 were retrospectively examined. Cases were excluded if crucial information was missing. Surgically induced astigmatism (SIA) was calculated from the pre–surgical and one–month follow up keratometry data using Holladay’s formula. With SIA as the dependent variable, a multiple regression model was run to identify any correlation with wound location and to control for independent predictors such as patient age, gender, diabetes mellitus, pseudoexfoliation, type of cataract, procedure technique, final lens position, attending case, and surgical preceptor. Results: 234 cases out of 495 were analyzed after filtering out those with incomplete data. The mean SIA by wound location was –0.52 ± .17 Diopters (D) temporally (defined as 0 to 23° from the lateral), –.40 D ± .12 superior temporally (24 to 67°), –.69 D ± .16 superiorly (68 to 112°) and –1.03 D ± .27 superior nasally (113 to 157°). Wounds in the superior position (coefficient = –.693 D, p–value=.004) and superior nasal position (–.836 D, p=.018) were shown to be associated with an increased SIA relative to temporal cuts. Superior temporal wounds, however, did not show a statistically significant difference in SIA (–.266 D, p=.378) compared to temporal incisions. The SIA difference between attending and resident cases was not statistically significant (–.124 D, p=.556). Age (–.020 D, p=.046) and degree of anterior sub–capsular cataract (–.419 D, p=.045) each showed a negative relation with the amount of SIA. One of the attendings presented a positive association with SIA when compared to the other (.602 D, p=.003). Intraocular lenses placed in the sulcus (1.018 D, p=.014) also showed a positive correlation when compared to those placed in the bag. Conclusions: Our data demonstrates that the temporal approach is associated with less SIA regardless of the primary surgeon’s expertise. It also indicates no statistically significant correlation between attending versus resident cataract extractions with regard to SIA. Independent predictors that show a significant correlation include age, final lens position, degree of anterior sub–capsular cataract, and attending doctor involved. These predictors, if confirmed in prospective studies, can help surgical preceptors establish the refractive prognosis of a given case.
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