|
THE flexible iris-claw phakic IOL (Artiflex, Ophtec) provides myopic patients the safety and efficacy of the parent Artisan implant combined with the advantages of small incision surgery, said investigators who reported their initial results with the lens at the XXI Congress of the European Society of Cataract and Refractive Surgeons. The flexible version of the iris-claw implant is available in powers to correct between -2.0 D and -12.0 D of myopia. It features flexible PMMA claws and a 6.0 mm convex-concave optic made of a silicone material with a high refractive index. The Artiflex has an overall length of 8.5 mm and is extremely thin, allowing it to be inserted through a self-sealing, 3.2 mm incision. The European clinical trial of the Artiflex IOL has enrolled 88 eyes so far, and results from early follow-up show that the small-incision, anterior chamber phakic IOL is associated with excellent accuracy, early and stable good visual acuity, and no significant complications. "The Artiflex shares the exceptionally good refractive and visual outcomes that have been associated with the Artisan IOL and over time is expected as well to be free from complications such as induction of cataract formation and pupil distortion that have occurred with other phakic IOLs," said Antonio Marinho MD. "Our early results with the Artiflex are very promising and we look forward to the development of a toric version of this small-incision phakic IOL," concurred Camille Budo MD.
Dr. Marinho reported results from his series of 14 eyes of 11 patients with SE values ranging from -6.0 to -11.75 D (mean -9.0). Follow-up for his series ranged from two to five months, with half of the eyes being seen at the three-month visit. Efficacy, calculated by dividing post-op UCVA by pre-op BSCVA, was 100%, indicating patients are seeing the same without correction after surgery as they did with glasses or contact lenses before Artiflex implantation. The accuracy of the refractive outcomes was impressive, with 100% of eyes being within 0.5 D of emmetropia, Dr. Marinho said. "Some eyes have slight residual astigmatism as we are enrolling patients with up to 2.0 D of cylinder," he explained. BSCVA was unchanged in 50% of eyes, increased by one or two lines in six eyes, and one eye showed a loss of two lines of BSCVA. That loss occurred at three months after surgery and was associated with the development of iris pigment precipitates. "This patient has just started on steroid treatment and has not yet returned for follow-up, but I am convinced the precipitates will disappear and this complication will not be important," Dr. Marinho said. Three other eyes also were found to have iris pigment precipitates. However, they were more minimal, disappeared with no treatment, and in no case interfered with visual acuity. No patient has spontaneously reported glare or problems with night driving, although when specifically queried, six patients reported experiencing mild glare. "None of the patients were complaining about visual symptoms and we also know from experience with the Artisan that glare improves with time," Dr. Marinho said. Endothelial cell counts are also being monitored as part of the safety evaluation, and mean endothelial cell count in this small group actually increased from 2,408 to 2,504 cells/mm3. "The follow-up is very short and no conclusions can be drawn from these data, but we do know that Artiflex implantation is atraumatic surgery," Dr. Marinho said. Dr. Budo has implanted the Artiflex in 41 eyes, of which 35 were seen at 1 month, 19 at 3 months, and 3 at 7 months. SE for his 41 eyes ranged from -2.0 to -12.0 D, all eyes had less than -1.5 D of astigmatism, and pre-operative UCVA ranged from -0.05 to 0.30. "If a phakic IOL procedure is excellent for eyes with high myopia greater than -8.0 D, why not for eyes with -2.0 D?" said Dr. Budo. In this larger series, Dr. Budo achieved the same excellent predictability as Dr. Marinho. On the first postoperative day, 100% of eyes were within half a dioptre of emmetropia and by one week, SE ranged from -0.25 to +0.5 D. At the first day after surgery, UCVA was at least 0.70 in all eyes, at least 0.90 in 34 (83%), and 1.0 in 28 (68%) eyes. Of eyes seen at one week and one month, 86% and 74%, respectively, had UCVA of at least 1.0, and UCVA was 1.00 in all three eyes seen at seven months. Best-corrected visual acuity was unchanged or improved after surgery in all eyes. At one week and three months, mean endothelial cell count was decreased by less than 0.5% from the preoperative level. Although neither Dr. Budo nor Dr. Marinho reported any cases of posterior synechiae development among the eyes implanted with the Artiflex IOL, Dr. Budo noted that results of a recent e-mail survey he conducted to gather information for a textbook he was preparing on the iris-claw phakic IOL showed it to be the most commonly reported adverse event. "Encouragingly, 95% of surgeons who responded had experienced no complications with the Artisan IOL, but formation of posterior synechiae was the most frequent occurrence for the 5% who did," said Dr. Budo. To minimise that risk, he recommended that candidates for the iris-claw anterior chamber phakic IOL be evaluated preoperatively with anterior chamber ocular coherence tomography (IOLMaster, Carl Zeiss Meditec). "Using this technology can allow the surgeon to investigate the configuration of the iris with and without accommodation and with a simulated IOL in place to identify eyes where there is limited space between the implant and a protruding or vaulted iris," Dr. Budo said. He added that the real-time OCT studies also prove there is no contact between the Artisan/Artiflex IOL and either the endothelium or anterior capsule, which is consistent with the lack of reported problems with cataracts and endothelial cell loss. Implantation of the Artiflex IOL follows many of the same steps used for the Artisan with the most notable exception being for the enclavation technique. The procedure begins with creation of two paracentesis wounds at 10 o'clock and 2 o'clock and filling of the anterior chamber with cohesive viscoelastic. Then a 3.2-mm clear corneal incision is made with a diamond blade at 12 o'clock . The Artiflex IOL is hooked and fixated onto a spatula and placed into the anterior chamber through an unenlarged incision. The spatula is moved out to release the IOL, which is manipulated into position for enclavation. The enclavation is performed with a specially developed implantation forceps and using the tips only to grasp the PMMA haptics, not the optic as is done when implanting the Artisan. "The spatula and forceps needed for Artiflex implantation are inexpensive and the IOL unfolds in a very controlled manner in the viscoelastic filled anterior chamber without touching the endothelium or anterior capsule," Dr. Budo said. The surgeon then performs iridectomy/iridotomy, if it has not been done previously, viscoelastic is removed with irrigation, and the wound hydrated with saline only, he added.
Antonio Marinho MD Camille Budo MD
|
