Surgically induced astigmatism after phacoemulsification with and without correction for posture-related ocular cyclotorsion: Randomized controlled study
Presented at the annual conference of the Irish College of Ophthalmologists, Kilkenny, Ireland, May 2009, and the XXVII Congress of the European Society of Cataract & Refractive Surgeons, Barcelona, Spain, September 2009.
Received 26 May 2009; received in revised form 29 July 2009; accepted 8 October 2009.
Purpose
To report the impact of posture-related ocular cyclotorsion on one surgeon's surgically induced astigmatism (SIA) results and the variance in SIA.
Setting
Institute of Eye Surgery, Whitfield Clinic, Waterford, Ireland.
Methods
This prospective randomized controlled study included eyes that had phacoemulsification with intraocular lens implantation. Eyes were randomly assigned to have (intervention group) or not have (control group) correction for posture-related ocular cyclotorsion. In the intervention group, the clear corneal incision was placed precisely at the 120-degree meridian with instruments designed to correct posture-related ocular cyclotorsion. In the control group, the surgeon endeavored to place the incision at the 120-degree meridian, but without markings.
Results
The intervention group comprised 41 eyes and the control group, 61 eyes. The mean absolute SIA was 0.74 diopters (D) in the intervention group and 0.78 D in the control group; the difference between groups was not statistically significant (P>.5, unpaired 2-tailed Student t test). The variance in SIA was 0.29 D2 and 0.31 D2, respectively; the difference between groups was not statistically significant (P>.5, unpaired F test).
Conclusions
Attempts to correct for posture-related ocular cyclotorsion did not influence SIA or its variance in a single-surgeon series. These results should be interpreted with full appreciation of the limitations of currently available techniques to correct for posture-related ocular cyclotorsion in the clinical setting.
Financial Disclosure
No author has a financial or proprietary interest in any material or method mentioned.
From the Department of Ophthalmology (Dooley, Charalampidou, Malik, Beatty), Waterford Regional Hospital, the Institute of Eye Surgery (Dooley, Charalampidou, Malik, Ormonde, Molloy, Beatty), Whitfield Clinic, and the Waterford Institute of Technology (Beatty), Waterford; Department of Optometry (Loughman), School of Physics, Dublin Institute of Technology, Dublin, Ireland
Corresponding author: Ian Dooley, MRCOphth, Institute of Eye Surgery, Suite 14, Whitfield Clinic, Cork Road, Waterford, Ireland.
ABSTRACT