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Lei Zheng, John C Merriam, Lei Zheng; The effect of toric and non-toric IOLs on refractive cylinder after cataract surgery. Invest. Ophthalmol. Vis. Sci. 2014;55(13):4192.
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© ARVO (1962-2015); The Authors (2016-present)
The selection of a toric intraocular lens is based on the keratometric cylinder before surgery. This study compares the change in refractive cylinder after cataract surgery with a toric IOL to the change in refractive cylinder with a spherical IOL.
This retrospective study includes 32 eyes of 21 patients who had a toric lens (Alcon AcrySof IQ) and 95 eyes of 80 patients who had a spherical IOL (Alcon AcrySof SN60WF). The surgeon (JCM) selected the IOL with the Zeiss IOLMaster and the Alcon AcrySof toric online calculator and performed all procedures with a temporal 2.2 mm incision. Corneal cylinder also was measured preoperatively with a manual keratometer (Bausch and Lomb). At least 4 months postoperatively the corneal keratometric cylinder was measured again with the manual keratometer, and the manifest refraction was recorded. The change in both the keratometric and the refractive cylinder after surgery was calculated for the toric and spherical IOL groups. The T-test was used to determine the significance of the differences between the two groups.
The mean corneal cylinder for the toric lens group (measured with the manual keratometer) before surgery was 1.64 +/- 0.78 diopters and 1.68 +/- 0.85 diopters after surgery. The mean keratometric corneal cylinder before surgery for the spherical lens group was 1.26 +/- 0.46 diopters and 1.17 +/- 0.63 diopters after surgery. The manifest refractive cylinder power after surgery was 0.57 +/- 0.34 diopters for the toric lens group and 0.95 +/- 0.69 diopters for the spherical lens group. There is no significant change in keratometric cylinder power after surgery in either group. With a spherical IOL there is no significant difference between mean preoperative keratometric corneal cylinder power and mean postoperative manifest cylinder power. With a toric IOL the mean postoperative cylinder power is significantly less than the mean preoperative keratometric cylinder power.
Compared to a spherical IOL, a toric IOL can reduce significantly the manifest refractive cylinder power after surgery.
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