Vector analysis of astigmatism correction after toric intraocular lens implantation.

PURPOSE: To determine astigmatic changes by vector analysis and postoperative refractive and visual outcomes after implantation of the monofocal aspheric bitoric AT Torbi 709M toric intraocular lens (IOL).

SETTING

Three centers in Salzburg, Austria, and Alicante and San Sebastián, Spain.

DESIGN

Prospective interventional case series.

METHODS

Preoperative and postoperative visual acuity, subjective and objective refractions, and corneal radii using a topographer were examined in all patients. All patients had postoperative examinations within the first week and at 6 to 12 weeks. Astigmatic changes were evaluated using the Alpins vector method based on 3 fundamental vectors as follows: target induced astigmatism (TIA), surgically induced astigmatism (SIA), and difference vector. The various relationships between these 3 vectors were calculated, providing an extensive description of the astigmatic correction achieved.

RESULTS

Eighty-eight eyes (71 patients) were included. Postoperatively, refractive cylinder was reduced significantly (P < .001), concurrent with visual improvement. The mean magnitude of the SIA vector (2.54 diopters [D] ± 1.21 [SD]) was slightly higher than the mean magnitude of the TIA vector (2.37 ± 1.15 D) at the last follow-up. The mean difference vector was 0.46 ± 0.46 D, the mean magnitude of error was 0.16 ± 0.46 D, and the mean correction index was 1.09 ± 0.21, all indicating minimal overcorrection at 3 months that remained stable during the follow-up.

CONCLUSION

Implantation of the toric IOL was safe and effective for the treatment of eyes with cataract in combination with preexisting regular corneal astigmatism over a short-term follow-up.

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