IOL ADVANCES

A novel one-piece hydrophobic acrylic IOL featuring an aspheric design customised for Japanese eyes (W-60; Eternity Natural Uni, Santen) is safe and provides excellent visual and refractive outcomes after cataract surgery, reported ophthalmologists from Toho University School of Medicine, Tokyo, Japan, at the 26th Asia-Pacific Association of Cataract & Refractive Surgeons Annual Meeting in Singapore. The IOL optic is constructed of the same material found in the Eternity IOL (Santen), which was first marketed in Japan in 2008, and contains a blue lightfiltering chromophore. The optic measures 6.0mm in diameter, and based on Japanese population-specific spherical aberration (SA) data, it has -0.13 microns SA at the corneal plane.

“The asphericity of the Eternity Natural Uni is designed to optimise quality of vision for the Japanese eye. It was chosen to achieve a total ocular SA of +0.1 microns, which represents the average for a 25-year-old Japanese person, and takes into account that the corneal SA in Japanese eyes averages +0.23 microns throughout adult life,” explained Nanae Yamazaki and Shinichiro Kobayakawa MD, PhD, Department of Ophthalmology, Toho University.

Dedicated injector system

Results after implantation of the Eternity Natural Uni IOL were analysed in a retrospective review of data from 106 consecutive eyes of 86 patients, of which 72 eyes were seen at three months. All surgeries were performed through a 2.8mm sclerocorneal incision with implantation of the IOL into the capsular bag using a dedicated injector system (Accuject UniFit, Santen).

Mean SA was -0.21 ± 0.91 microns preoperatively, 0.029 ± 0.03 at one month, and -0.03 ± 0.24 microns at three months. Mean logMAR BCVA was 0.28 ± 0.64 preoperatively and 0.014 ± 0.24 at three months.

Mean postoperative refractive error improved during early follow-up from -0.73 ±0.76 D at one week (100 eyes) to -0.46 ± 0.69 D at three months. The achieved refractive outcome at three months was ± 1.0 D of intended in 82 per cent of eyes, ± 0.50 D in 43 per cent, and ± 0.25 D in 19 per cent. The back-calculated A constant was 118.9 compared with the manufacturer’s recommended value of 119.1 that was used for selecting IOL power in this initial cohort.

Excellent clarity

There were no problems with IOL stability, clarity or posterior capsule opacification (PCO) in the series. “The hydrophobic acrylic material used in the Eternity Natural Uni IOL was developed by Advanced Vision Science, a Santen company, and through a licensing agreement and is also found in the enVista IOL (Bausch + Lomb) in markets outside of Japan. Clinical experience with this material over the past five years together with findings from animal studies establish that it has advantages for being glisteningsfree and maintaining excellent clarity longterm,” said Dr Kobayakawa.

He added that the Eternity Natural Uni lens has an advanced haptic design that maintains positional stability, and it was designed with features to prevent PCO. In addition to having a sharp optic edge, the lens incorporates an additional haptic-optic barrier edge (Advantedge) that prevents migration of lens epithelial cells via the haptic-optic junction.