Tadros Athanassius, Habib Maged, Tejwani Deepak, Von Lany Hirut, Thomas Peter
Royal Eye Infirmary, Dorset County Hospital, Dorchester, Dorset, United Kingdom.
J Cataract Refract Surg. 2004 Feb;30(2):414-7. doi: 10.1016/S0886-3350(03)00649-7.
To evaluate the effect of on-axis opposite clear corneal incisions (OCCIs) in phacoemulsification on reducing preoperative corneal astigmatism and to predict the astigmatic outcome of the incisions.
Royal Eye Infirmary, Dorset County Hospital, and Winterbourne Hospital, Dorchester, Dorset, and the Department of Ophthalmology, East Somerset Hospital, Yeovil, Somerset, United Kingdom.
This prospective study included all patients (n = 103) who had on-axis OCCIs as a part of routine phacoemulsification with foldable intraocular lens (IOL) implantation performed by 1 surgeon during 2000. Keratometry was done 6 to 8 weeks postoperatively. The differences in the preoperative and postoperative corneal astigmatism and corneal spherical equivalent (SE) were recorded. Surgically induced astigmatism (SIA) was calculated using vector analysis.
The mean reduction in corneal astigmatism was 0.50 diopter (D) (P<.001). The mean SIA was 1.57 D (95% confidence interval [CI], 1.42 to 1.71). There was a weak association between the SIA and the patient's age and axis of preoperative astigmatism. The mean change in SE was +0.02 D (95% CI, -0.08 to +0.12).
Results indicate that on-axis OCCIs are a reliable and practical way of reducing preexisting corneal astigmatism. The change in SE was negligible and thus can be ignored during biometry.
