Cataract surgery with toric intraocular lens implantation in keratoconus

Session Details

Session Title: Toric IOLs

Session Date/Time: Sunday 14/09/2014 | 16:30-18:30

Paper Time: 16:54

Venue: Capital Hall B

First Author: : E.Hrdličková CZECH REPUBLIC

Co Author(s): :    L. Filipová   Z. Hlinomazová   M. Filipec        

Abstract Details

Purpose:

The aim of our study was to evaluate the refractive outcomes after cataract surgery with implantation of toric intraocular lens in patients with stable keratoconus and cataract, and to investigate the IOL power calculation based on different methods of keratometry measurements.

Setting:

European Eye Clinic Lexum, Prague, Czech Republic

Methods:

Our study comprised 16 patients (22 eyes) with stable keratoconus who had cataract surgery by phacoemulsification with implantation of toric intraocular lenses (AT Torbi 709M, AcrySof IQ Toric and Tecnis Toric). The mean patient age was 62 years (47-80 years). We analysed preoperative and postoperative decimal uncorrected distance visual acuity (UDVA) and best corrected distance visual acuity (CDVA) and manifest refraction. We compared the IOL power calculation obtained based on keratometric readings by IOL Master, True Net Power (TNP) map, and topographic map. Furthermore, we estimated the influence of location of the apex of keratoconus, I-S index and maximal keratometry (Kmax) on postoperative sphere, spherical equivalent (SE) and astigmatism.

Results:

The mean UDVA improved from preoperative 0.18±0.19 to postoperative 0.65±0.25. Preoperative mean CDVA was 0.61±0.25. Postoperatively, CDVA was 0.92±0.15. Manifest refractive astigmatism decreased from -3.20±2.10 D (range -7 to 0 D) before surgery to 0.65±0.65 D (range -2 to 0 D) at 6-month visit. The mean SE improved from 5.86±5.84 D to postoperative 0.23±0.95 D. When IOL power was calculated based on keratometry from TNP map the mean predicted postoperative sphere was -1.77±1.45 D (range -5.5 to 1.05 D). The postoperative sphere when calculation was based on IOL Master was +1.00±1.30 D (range -0.75 to 3.25). When based on topographer it was +0.14±0.73 D (range -0.75 to 1.25). These values did not significantly differ (P=0.14). In 12 eyes with paracentral inferior location of keratoconus the mean postoperative SE was 0.48±1.10, while in 10 eyes with central location the mean SE was 0.06±0.63. I-S index did not have significant influence on postoperative sphere (P=0.31), SE (P=0.76), and astigmatism (P=0.05). Kmax also did not have influence on postoperative sphere (P=0.42), SE (P=0.16), and astigmatism (P=0.11). Rotation of a lens was required in 3 eyes. No other complications were noted.

Conclusions:

Cataract surgery with implantation of toric intraocular lens in patients with keratoconus can significantly improve the best corrected visual acuity. According to our results the calculation of IOL power from keratometry values based on topography and IOL Master is a more suitable method than calculation based on True Net Power, as the former leads to lower postoperative residual refractive error. The postoperative results depend on the location of the apex of keratoconus. In eyes with central keratoconus better results were obtained. I-S index and K max had no significant influence on postoperative refractive outcome.

Financial Interest:

NONE