IOL OUTCOMES

Surgeons using the monofocal and toric versions of the single-piece, aspheric hydrophobic acrylic enVista IOL (Bausch + Lomb) give the implant good early reviews with high ratings for patient outcomes. Speaking at the 26th Asia-Pacific Association of Cataract & Refractive Surgeons, Hyo Myung Kim MD, PhD, reported results achieved in a consecutive series of 33 eyes of 30 patients followed to three months after implantation with the monofocal aspheric enVista IOL (MX60). The surgeries were performed at the Anam Hospital of the Korea University College of Medicine, Seoul, South Korea, where Dr Kim is a professor of ophthalmology. The patients had typical characteristics for a cataract surgery population, with a mean age of 68 years. Follow-up ranged from just one month to 4.7 months.

Dr Kim described the BCVA results as “nearly perfect”; 31 (92 per cent) eyes achieved 20/20 or better BCVA. Poorer vision in the remaining two eyes was explained by comorbidities. Refractive outcomes were also good with achieved mean SE at one month and three months being very close to the target refraction (-0.30 ± 0.74 D and-0.14 ± 0.54 D vs. -0.40 ± 0.76 D respectively). Consistent with marketing claims for the enVista IOL that emphasise its glistening- free material and design characteristics for minimising posterior capsular opacification (PCO), Dr Kim reported that retroillumination photography found no evidence of PCO within the central 3.0mm of the capsule. He observed no cases with glistenings in the IOL material. “However, longer follow-up is needed to assess the optical clarity of the lens and the posterior capsule,” Dr Kim said.

Dean Corbett MD, private practice, Auckland, New Zealand, reported on his initial experience using the toric version of the enVista IOL (MX60T) in 12 eyes with astigmatism ranging from 0.93 to 3.32 D (mean 1.53 D). At the time of the surgeries, the IOL was available in three cylinder powers correcting 1.25, 2.00, or 2.75 D at the IOL plane. The toric line is now being expanded with the addition of models correcting 3.50, 4.25, 5.00, and 5.75 D of astigmatism in the IOL plane. Dr Corbett performed the procedures through a clear corneal temporal incision measuring 2.4 to 2.65mm and used the manufacturer’s free online calculator (www.envistatoric.com) to determine astigmatic power and axis of implantation. His technique included preoperative axis marking at the slit-lamp using a needle and gentian violet staining to guide alignment of the IOL intraoperatively.

Postoperative IOL rotation was measured using a reticule on the slit-lamp, and the results showed good in-the-bag stability of the toric IOL. At three months, mean rotation from surgery was five degrees, and 11 (92 per cent) of the 12 IOLs were within seven degrees of intended axis. In the one outlier, the IOL was 15 degrees off axis, but the IOL had rotated only two degrees since postoperative day one, and the patient had good vision and declined additional intervention, Dr Corbett reported. “My experience in this series compares well with the outcomes in the US FDA enVista toric trial where postoperative rotation was five degrees or less in 92 per cent of 101 IOLs evaluated at three to six months after surgery,” he said. In addition to being glistening-free, the novel hydrophobic acrylic material of the enVista IOL is noteworthy for its surface hardness and rigid nature. The surface hardness increases the IOL’s resistance to scratching from surgical manipulations, and its rigidness results in slow unfolding. Dr Corbett pointed out that the latter characteristic allows for precise positioning of the toric IOL within the capsular bag, as it enables implant rotation to the desired axis as well as thorough removal of the ophthalmic viscosurgical device (OVD) from behind the lens.

However, Dr Kim noted that the rigidness of the IOL created some minimal handling concerns in terms of difficulties with unloading and unfolding. To address the latter issues, and taking into account that the hydrophobic acrylic polymer transitions from a rigid to a more flexible material when the temperature exceeds 28o to 30oC, Dr Kim suggested using warm OVD (30o to 33o C) when filling the anterior chamber and capsular bag for IOL implantation