Visual function and patient experience after bilateral implantation of toric intraocular lenses ARTICLE

for the Canadian Toric Study Group* PURPOSE: To evaluate the efficacy, stability, predictability, and patient-reported outcomes of bilateral toric intraocular lens (IOL) implantation in cases of cataract with preexisting astigmatism. SETTING: Fourteen universities, hospitals, or private practices, Canada. METHODS: Patients with cataracts and corneal astigmatism from 1.00 to 2.50 diopters (D) were included in a prospective study of bilateral AcrySof toric IOL implantation. Binocular uncorrected distance visual acuity (UDVA), manifest refraction, and IOL rotational stability were assessed 1 day and 1, 3, and 6 months postoperatively. Patients completed a questionnaire that assessed spectacle independence, visual disturbances, and satisfaction with vision (1 Z completely unsatisfied; 10 Z completely satisfied) preoperatively and 3 and 6 months postoperatively. RESULTS: The study included 117 patients (234 eyes). The binocular UDVA was 20/40 or better in 99% of patients and 20/20 or better in 63% of patients. The mean residual refractive astigmatism was 0.4 D G 0.4 (SD). The spherical equivalent was within G0.5 D of target in 77% of eyes. At last observation, IOL alignment was within G5 degrees in 91% of eyes and within G10 degrees in 99%. Sixty-nine percent of patients reported never using distance spectacles. The frequency and severity of halos and glare were significantly reduced from preoperatively to postoperatively. Satisfaction with vision was rated 7 or higher by 94% of patients. CONCLUSION: Bilateral implantation of toric IOLs yielded excellent and stable visual outcomes that patients rated as highly satisfactory. Many cataractous eyes have some amount of clinically significant astigmatism. 1 In a definitive biometry study of 7500 cataractous eyes, 1 corneal astigmatism of 0.75 to 1.50 diopters (D) was observed in 41% of patients and of more than 1.50 D in 18% of patients. Implantation of toric intraocular lenses (IOLs) is an option to compensate for corneal astigmatism in cataract patients. An important criterion for evaluating toric IOLs is their rotational stability because alignment is critical in compensating for corneal cylinder and thus producing good uncorrected distance visual acuity (UDVA). Each degree of rotation causes an average loss of cylinder power of approximately 3%; thus, when an IOL rotates 30 degrees there is no astigmatic correction, although there is a change of axis. 2,3 With the AcrySof toric IOL (Alcon, Inc.), alignment was within G5 degrees in 78% of eyes in clinical trials (product information, Alcon, Inc., 2005) and was within G5 degrees in 77% to 95% of eyes in recent studies