Corneal astigmatism correction with opposite clear corneal incisions or single clear corneal incision: Comparative analysis
Accepted 7 April 2006.
Purpose
To compare the astigmatic correcting effect of paired opposite clear corneal incisions (OCCIs) on the steep axis with that of single clear corneal incisions (CCIs) in cataract patients having phacoemulsification.
Setting
Rajendra Prasad Centre for Ophthalmic Sciences, AIIMS, New Delhi, India.
Methods
This randomized prospective clinical study comprised 40 eyes of 40 patients with topographic astigmatism of more than 1.50 diopters (D). Paired 3.2 mm OCCIs were made in the steep axis in Group 1 and single CCIs in Group 2. Preoperative evaluation included uncorrected visual acuity, refraction, applanation tonometry, dilated fundoscopy, biomicroscopic examination, keratometry, and topography. The steep axis was marked before sub-Tenon's anesthesia was given and routine phacoemulsification was performed through a 3.2 mm CCI on the steep axis. An additional opposite 3-step self-sealing CCI was made in Group 1. Patients were examined 1, 4, and 12 weeks postoperatively. Visual acuity, refraction, keratometry, and topography were evaluated.
Results
The mean preoperative and postoperative topographic corneal astigmatism was 2.51 D ± 0.92 (SD) and 0.91 ± 0.54 D, respectively, in Group 1 and 2.16 ± 0.80 D and 1.57 ± 0.70 D, respectively, in Group 2. Mean astigmatic correction was 1.66 ± 0.5 D and 0.85 ± 0.75 D in Group 1 and Group 2, respectively. Mean surgically induced astigmatism, measured by a vector-corrected method, was 1.66 ± 0.50 D and 0.85 ± 0.75 D in Group 1 and Group 2, respectively (P = .00). The coupling ratio was −0.96 in Group 1 and −0.87 in Group 2. The spherical equivalent was +0.23 ± 0.41 D in Group 1 and +0.11 ± 0.17 D in Group 2 at 12 weeks. Uncorrected visual acuity was better in Group 1 than in Group 2 (P = .032). There was no difference in best corrected visual acuity between the groups. There were no incision-related complications.
Conclusion
Paired OCCIs were predictable and effective in providing an enhanced effect for correcting preexisting corneal astigmatism in cataract surgery.
From the Rajendra Prasad Center for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India
Corresponding author: Sudarshan Khokhar, MD, Professor of Ophthalmology, Rajendra Prasad Center for Ophthalmic Sciences, All India Institute of Medical Sciences, 110029, New Delhi, India.
No author has a proprietary or financial interest in the materials or methods mentioned.
ABSTRACT