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Rotational stability of a single piece hydrophobic acrylic intraocular lens in patients with high myopia
Session Title: Toric IOL Outcomes
Session Date/Time: Monday 07/10/2013 | 16:30-18:30
Paper Time: 17:12
Venue: Auditorium (First Floor)
First Author: : F.Fasce ITALY
Co Author(s): : A. Spinelli K. Knutsson G. Bolognesi P. Mauceri
To measure the amount of rotation of a single piece hydrophobic acrylic intraocular lens (Acrysof® IQ SN60WF, Alcon) in patients with high myopia and compare results to an emmetropic control group. Patients affected by high degree myopia have several anatomical differences that must be taken into account when planning and performing cataract surgery. Studies have shown that eyes with greater axial length have larger capsular bags and are associated with decreased IOL stability and early IOL rotation. Evaluating the rotational stability of this monofocal single piece IOL is mostly important in myopic eyes considering that the toric equivalent has the same platform.
San Raffaele Scientific Institute, Department of Ophthalmology, Milan, Italy
Fifteen patients with high myopia and axial length greater than 26.0 mm and fifteen emmetropic patients with an axial length between 23.0 and 24.0 mm were enrolled for this prospective comparative study. The patients were scheduled to undergo cataract surgery in one eye. We performed standard phacoemulsification with temporal corneal incisions. An Acrysof® SN60WF IOL was implanted in the capsular bag aiming for an oblique orientation of the haptics (about 45° or 135°). The viscoelastic material was carefully removed, especially from behind the IOL, and the optic plate was pushed down against the capsular bag. A slit lamp digital image was taken 1 hour postoperatively and 1, 15 and 30 days postoperatively. The images were analyzed using photo editing software following a standard and previously described method. First a standard axis line was traced using an episcleral vessel as a reference point and then a second line was traced passing through the geometric center of the IOL and haptics. The angle between the two lines was measured at the different time intervals and rotation of the IOL was calculated by obtaining the difference between the various angles. Statistical analysis was performed using the Mann Whitney test.
The patients in the high degree myopia group had a mean axial length of 27.86 mm compared to 24.21 mm in the emmetropic control group. IOL rotation was significantly greater in the myopic group (3.1°) compared to the emmetropic group (1.1°) (p <0.05). In all cases IOL rotation remained stable after 15 days, indicating that adherence of the IOL to the anterior and posterior occurs in the early postoperative phases. A great amount of IOL rotation (>15°) was not observed in any case.
Our results confirm that IOL rotation is significantly greater in eyes with longer axial length compared to eyes with average axial length. Degree of rotation was similar to other studies, and was considered to be acceptable in the high degree myopia group, thus demonstrating that the Acrysof® SN60WF IOL has adequate rotational stability