Evaluation of a new toric IOL optic by means of the ORA system: the effect of IOL misalignment on cylinder reduction

Session Details

Session Title: Interactive Free Paper Session: Pseudophakic IOLs/ Toric

Session Date/Time: Monday 15/09/2014 | 16:30-18:30

Paper Time: 17:58

Venue: Capital Hall B

First Author: : E.Mertens BELGIUM

Co Author(s): :                  

Abstract Details

Purpose:

To intraoperatively compare the effect of misalignment of the Precizon and Lentis toric intraocular lenses (IOLs) on refraction by means of the ORA system and to compare postoperative outcomes.

Setting:

Medipolis Eye Center, Antwerp, Belgium

Methods:

Prospective, randomized, comparative study in which patients with cataract and pre-existing corneal astigmatism underwent routine cataract surgery with bilateral implantation of a toric IOL model. Intraoperative wavefront aberrometry (ORA system) was used to assess the effect of IOL misalignment on cylinder reduction after which the lenses were rotated to the intended axis and surgery was completed. Preoperative biometry measurements were done using an optical biometer (IOL master). Lens powers were calculated using the respective manufacturer’s online calculators. Emmetropia was targeted. Intraoperative refraction was measured at 10°, 5° and at 0° (mis)alignment using the Optiwave Refractive Analysis (ORA) system wavefront aberrometer (WaveTec Vision Systems, Aliso Viejo, CA, USA). Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction and IOL misalignment were evaluated 1 month postoperatively. Postoperative IOL misalignment was assessed using a KR-1W Wavefront analyzer (Topcon, Tokyo, Japan).

Results:

Toric IOL implantation in 10 eyes in each subgroup resulted in an average of 1,6° rotation with the Precizon IOL and an average of 2,2° with the Lentis Toric IOL. For every degree of error in a toric IOL’s rotational misalignment, there is a 3.3 percent decrease in the correction of astigmatism. So If a toric IOL is misaligned by 10 degrees, the astigmatism will be 33 percent undercorrected. If the toric IOL is misaligned by 30 degrees, there will be no astigmatism correction. This is what we found with the Lentis Toric IOL by deliberately misaligning 10° and 5°. Surprisingly we did not get the same results with the Precizon IOL. By misaligning 10° the undercorrection was on average 18% instead of the expected 33% as measured with the ORA and the average undercorrection with 5° misalignment was 9%.

Conclusions:

The new toric optic IOL Precizon gave similar results in terms of rotation one month postoperatively but performed significantly better in astigmatism correction and was less sensitive to misalignment in respect to the Lentis Toric IOL. Longer follow-up and a larger series is needed to support this findings.

Financial Interest:

One or more of the authors... travel has been funded, fully or partially, by a company producing, developing or supplying the product or procedure presented