Ankoris: a new toric IOL with insufficient rotational stability after cataract surgery

Session Details

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

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

Paper Time: 17:10

Venue: Capital Hall B

First Author: : K.Vandekerckhove SWITZERLAND

Co Author(s): :                  

Abstract Details

Purpose:

Proper alignment of a toric lens inside the capsular bag is a crucial factor influencing the efficacy of astigmatism correction during cataract surgery. The purpose of our study was to evaluate the rotational stability of Ankoris (PhysIOL SA), a new toric hydrophylic intraocular lense (IOL) with innovative haptic design (4-haptics design) and an overall diameter of 11.4 mm. To date, no studies examining the Ankoris toric IOL have been published.

Setting:

Vista Alpina Eye Clinic, Switzerland.

Methods:

Consecutive cataractous eyes with corneal astigmatism >1.25 diopters and normal axial length (22.7-24.5mm) were prospectively enrolled in our study. After uncomplicated phacoemulsification with incisions on the steep corneal axis, they were implanted with the Ankoris toric IOL (CYL power 1.5 and 2.25D). Alignment was done with corneal marking while sitting. Routine examinations were performed one day, one week, one month, and six months after surgery, measuring uncorrected and best corrected visual acuity, manifest refraction including residual refractive cylinder, and IOL rotation. The Ziemer Galilei 6 device was used for keratometry and biometric measurements, as well as for digital assessment of IOL alignment. Corneal astigmatism was calculated based on ray tracing, taking into account anterior and posterior astigmatism. Due to the poor IOL rotational stability evidenced early in the study, patient enrolment has been discontinued after 7 eyes. Patients continued being followed-up according to the initial study protocol.

Results:

Seven eyes of 6 patients were included in this study. Mean pre-operative ray-traced corneal astigmatism was 1.68 D (SD: 0.3 D). Uncorrected distance visual acuity was +0.17 logMAR (SD: 0.18), +0.17 logMAR (SD: 0.14), and +0.18 logMAR (SD: 0.14) at 1 week, 1 month and 6 months respectively. Residual refractive astigmatism 6 months after cataract surgery was 0.54 D ± 0.33 D. Mean absolute deviation from intended axis was 13.0° (2-30°, SD 11.1°) at 1 week, 15.0° (9-33°, SD 9.0°) at 1 month and 13.2° (3-35°, SD 11.5°) at 6 months. Three lenses (out of 7) rotated more than 10° at one week. One eye needed repositioning at 2 weeks because of IOL rotation of 25° resulting in 2.5 D of refractive astigmatism. Between 1 week and 6 months, 9.2° (5-15°, SD 4.5°) of rotation was observed, either along or opposite to the direction of rotation during the first postoperative week. In one eye, 10° of counter-clockwise rotation was observed during the first week, whereas between one week and 3 months 15° of clockwise rotation occurred. We photo documented the progressive bending of the haptics against the optic along with the onset of capsular fibrosis, resulting in 15° clockwise rotation.

Conclusions:

The Ankoris IOL did not demonstrate sufficient rotational stability after phakoemulsification of medium to severe cataracts. Rotational instability occured during an early and a late phase. We postulate that IOL geometry (diameter and haptic design) allowed for early rotation (first week). In the later phase of rotation, the haptics did not resist the desequilibrating forces from capsular fibrosis. Loss of haptic memory (due to design and material issues) seemed to be the most likely cause.

Financial Interest:

NONE