Vector analysis of astigmatic changes after cataract surgery with toric intraocular lens implantation.

PURPOSE: To analyze the astigmatic changes after cataract surgery with toric intraocular lens (IOL) implantation and determine the relationship between these changes and the final visual outcomes.

SETTING

Vissum-Instituto de Oftalmológico de Alicante, Alicante, Spain.

DESIGN

Prospective case series.

METHODS

This study comprised eyes with visually significant cataract that had surgery with Acrysof toric IOL implantation. Refractive, corneal topography, internal astigmatism, and contrast sensitivity outcomes were evaluated over 6 months. The Alpins vectorial method was used to analyze the target (TIA) and surgically (SIA) induced astigmatism, difference vector, magnitude of error, flattening effect, and torque.

RESULTS

The study enrolled 27 eyes (21 patients). Postoperatively, there was a significant reduction in refractive cylinder (P < .01) with an associated visual improvement (P < .01). The magnitude of the SIA vector was significantly lower than the TIA 1 month and 6 months after surgery (P < .01). The mean magnitude of the difference vector was 0.91 diopter (D) ± 0.45 (SD) at 6 months, with no significant differences between postoperative visits (p > 0.19). The mean magnitude of torque vector was 0.59 ± 0.42 D at 6 months. There was a significant negative correlation between refractive cylinder and the magnitude of torque (r ≤ -0.54, P < .01) and the difference vector (r = -0.98, P < .01).

CONCLUSION

The toric IOL restored distance visual function in eyes with cataract and significant corneal astigmatism, although there was a small trend toward undercorrection related to misalignment of treatment.

FINANCIAL DISCLOSURE: No author has a financial or proprietary interest in any material or method mentioned.