Presbyopic Phakic IOL Promising in French Trial

By Cheryl Guttman

Georges D. Baikoff, MD

BARCELONA- Accumulating data indicate that the foldable, angle-supported bifocal phakic implant (Vivarte/GBR) is an excellent modality for correcting presbyopia, said its inventor Georges D. Baikoff, MD, director, centre for ophthalmology, Clinique Monticelli, Marseilles, France.

Clinical trials with the presbyopic phakic IOL began 18 months ago in the Czech Republic where Eva Volkva, MD, implanted six eyes of six patients aged 50 to 55 years old. All eyes were emmetropic with an addition of 2.50 D. The IOL was explanted in two patients due to lens oversizing. However, the remaining patients achieved 20/20 to 20/30 UCVA, could read J2 or better without correction, and have experienced no anatomical complications.

Under the French HURIET law, Dr. Baikoff launched a prospective study in August, 2001, at the Monticelli clinic. Patients eligible for participation have an anterior chamber depth >/=3-mm, an endothelial cell count at least 2500 cells/m2, an open angle, and no anterior chamber pathology. Ten eyes have been operated on in patients all aged 55 years old. All eyes were either emmetropic or had spherical errors between -3.0 D and +1.0 D with no astigmatism. LASIK was performed to correct residual myopia in 1 eye.
At last visit, residual refractive errors ranged from +0.50 D to -1.0 D and all eyes have distance UCVA of 20/30 or better and can read J2 or better. Patient satisfaction has been very high except for one individual who is concerned about having near and far vision but no intermediate vision, Dr. Baikoff reported.

"A Major Step Forward"
“The introduction of this presbyopic phakic IOL is a major step forward in refractive surgery as presbyopia correction is the remaining refractive surgery frontier. The efficacy and safety achieved in these initial patients is very encouraging, and we look forward to implanting it in eyes with higher refractive errors and/or astigmatism that will be corrected by LASIK. However, much further study is needed to characterize the performance and limitation of this implant,” he commented.

The presbyopic phakic IOL is based the one-piece tripod design of the Vivarte/GBR monofocal implant, but features a bifocal optic. It has semi-rigid PMMA haptics with hydrophilic acrylic haptic footplates, comes in three lengths: 12.0, 12.5, or 13.0mm, and can be implanted through a 3.2mm self-sealing incision.
The hydrophilic acrylic optic measures 5.5mm and has central and peripheral zones for distance vision and an intermediate zone with a +2.50 D add for near vision that allows successful correction of most presbyopes.

“This add corrects presbyopia in patients who are in the 51 to 59 year-old age range. For 50-year-olds, there is a slight overcorrection of +0.50 D and patients 60 years and older are slightly undercorrected by about -0.50 D. Both of those small errors are well-tolerated by patients. However, in the future we hope to modify the optical properties of the add zone in terms of surface, diameter, and power for more accurate correction,” said Dr. Baikoff.

The only complication encountered so far in recipients of the presbyopic phakic IOL has been some mild halos in dim light. Those symptoms have decreased over time and have not been bothersome enough in any individual to prompt a request for implant removal.
“When asked to compare discomfort associated with night time halos and that of presbyopia, the patients have unanimously preferred correction of their presbyopia,” Dr. Baikoff said.

Potential Pupil Problems…and Solutions
There remains a potential for pupillary ovalisation with this angle-supported IOL, although no cases have occurred. Systems for accurately measuring the internal diameter of the anterior chamber intra-operatively or pre-operatively are being developed, and their use will minimize the risk of pupillary ovalisation.

In a few months time, two pre-op measuring methods will be available. One is an optical digital sizer based on a retro-illumination system that should allow the surgeon to estimate, with a still undefined precision, the internal diameter of the anterior chamber Another company is working on an ultra high frequency ultrasound biomicroscopy device that should be able to give the exact anatomy of the anterior chamber with a 40µ risk of error. It would then be possible to provide the surgeon with a pre-sized, pre-powered phakic IOL. This would dramatically reduce the risk of pupillary ovalisation, explained Dr Baikoff.

Today, however, Dr. Baikoff noted that from the standpoint of safety, undersizing is preferred to oversizing when there is a question about which length implant to use.
“An implant that is slightly too small might rotate in the anterior chamber, but will not damage the endothelium if the footplates remain behind the Schwalbe ring. However, a device that is too large exerts pressure on the iris root and can cause pupillary ovalisation,” he explained.

Implantation of the presbyopic phakic implant has been facilitated with the development of folding systems that allow the IOL to unfold inside the anterior chamber parallel to the iris. One such system folds the implant into three parts and a second is available that folds it into four parts (M Folding ASICO, USA). In the future, the presbyopic phakic IOL implant should be available prefolded through the use of CIBAVision’s MemoryLens technology.

Dr. Baikoff is developing the presbyopic phakic IOL in collaboration with CIBAVision (Vivarte) and IOLTECH (GBR) as industrial partners.