A Comparison of the Accuracy of Toric Intraocular Lens Formulas

To compare the accuracy of the Abulafia-Koch, the Barrett, the Barrett Post ,the EVO , the new Holladay with total surgical-induced astigmatism, the Kane and and the Næser-Savini toric intraocular lens (IOL) power formulas using a large database of toric IOL refractive outcomes.Retrospective consecutive case series.One hundred seventy-two eyes of 172 patients who had a toric IOL inserted during surgery.One eligible eye from patients having uncomplicated cataract surgery with insertion of an Alcon SN6AT(2-9) IOL (Alcon Laboratories, Inc, Fort Worth, TX) from 1 surgeon were included in the study. pre-operative were measured using either the IOLMaster 500 or 700 (Carl Zeiss Meditec AG, Jena, Germany). Using vector calculation, the predicted postoperative refractive astigmatism was calculated for each formula. This was compared with the actual postoperative refractive astigmatism to give the prediction error.

Inclusion criteria

• uncomplicated cataract surgery with a temporal clear corneal incision,with preoperative biometry using either the IOLMaster 500 (softwareversions 5.5 and 7.7) or 700 (software version 1.50; Carl Zeiss Meditec AG, Jena, Germany)
• subjective manifest refraction performed by any of the orthoptists in the practice and measurement of the actual postoperative axis of the IOL alignment performed in the same visit an average of 1 or 3months after surgery.

Exclusion criteria

• any corneal disease (keratoconus, other ectasia, pterygium, or previous trauma);
• previous ophthalmic operations, including laser vision correction, vitrectomy, pterygium surgery, penetrating glaucoma surgery, or scleral buckling procedures
• intraoperative or postoperative complications
• postoperative corrected distance visual acuity worse than 6/9