Winter ESCRS meeting focuses on IOLs, wavefront technology

While phakic IOLs gain ground in refractive surgery, laser procedures increasingly employ aberrometry.

ROME – The future of refractive surgery lies in IOL technologies and in the application of wavefront technology to an increasingly wider range of indications. This was, in brief, the message that speakers at the winter meeting of the European Society of Cataract and Refractive Surgery brought to its 800 attendees. Most of the attention at the meeting here was devoted to these two topics.

IOLs in particular were the subject of discussion at all times, from the didactic courses to the symposia, from free papers to the live surgery sections.

Phakic IOLs old and new

Phakic IOLs had the star role at the meeting. If for some time their development has proceeded by trial and error, speakers said, their problems have now been mostly eliminated, their quality and design has been improved, and they are at present consolidating their role as a standard procedure for an increasingly wider range of refractive error.

It emerged at the meeting that a number of surgeons are now using less laser and more phakic implants. A preserved cornea, less induced optical aberrations and the reversibility of the procedure, together with the improved safety and efficacy of the new designs, are convincing arguments in favor of their use, surgeons said.

Long follow-up has demonstrated the safety of some of the oldest phakic IOL designs, such as the Ophtec Artisan, which has a good number of supporters. Its recently introduced foldable version, the ArtiFlex, is showing equally good results, according to Camille Budo, MD, and other speakers who have been implanting it during the last few months.

“The advantage is, of course, the small incision, which is what all phaco surgeons are aiming for,” Dr. Budo said.

The STAAR Surgical ICL also still has something to offer, according to some presenters. However, although the latest version of the ICL has improved its design, some concerns about secondary cataract were still expressed by speakers here.

Outcomes with CIBA Vision’s PRL were presented by more than one speaker.

“The preliminary results of the European study on 220 implants are promising. The fact that the lens floats, as proved by ultrasound biomicroscopy (UBM) and slit lamp, may be an important advantage of this phakic IOL, as it prevents contact with the crystalline lens,” said Carlos Moedas, MD.

A new lens that is showing great promise with more than a year of clinical application is the Vivarte Presbyopic, also from CIBA Vision, designed by Georges Baikoff, MD. What is new about this lens is the principle of applying multifocality for phakic presbyopes. The lens provides minus correction in the center for distance vision, an add for near vision in the middle part of the optical zone and again distance correction in the periphery.

“The results appear superior to other surgical techniques for the correction of presbyopia, with the additional advantage of reversibility,” Dr. Baikoff said. The Vivarte Presbyopic is foldable and injectable and maintains a safe distance from the endothelium even in flatter, hyperopic corneas, he said.

Enthusiastic consent was shown around the I-Care IOL from Corneal, designed by Philippe Sourdille, MD, a hydrophilic acrylic, one-piece injectable phakic IOL. The almost perfectly symmetrical design is the strong point of this lens, Dr. Sourdille said. It is “placed in the anterior chamber, not pressed, like with PMMA haptics, or attached as the Artisan,” said Dr. Sourdille. Forces are equally distributed on the four footplates.

The optic, as shown by UBM images, maintains an equal distance from the corneal endothelium and the surface of the crystalline lens, “a position which reflects excellent stability and safety,” he added. In the 151 eyes implanted in European countries, only three cases of pupil ovalization were reported, probably due to errors in the white-to-white measurement, Dr. Sourdille said.

The problem of sizing

The crucial problem of angle-to-angle and sulcus-to-sulcus estimation was raised by more than one speaker. The unanimous opinion was that white-to-white and other conventional ocular measurements are not adequate for planning safe phakic IOL surgery, and the use of more objective methods of evaluation was advocated.

The Ultralink Artemis 2 anterior segment scanning system, described by both Dan Reinstein, MD, and Carlo Lovisolo, MD, is not yet on the market. Prototypes of the system are in use by two centers in the United States and one in Italy. The Artemis 2, which was said to be “simply extraordinary” by Dr. Lovisolo, provides objective measurements of both angle-to-angle and sulcus-to-sulcus distances.

Speakers said other technology currently available, such anterior segment measurement with the Zeiss OCT or the IOLTECH LED Sizer, can be used to measure the angle-to angle distance.

New trends in aphakic IOLs

The attention given at the meeting to new IOL options for cataract surgery attested to a growing interest in the refractive aspects of the procedure.

Development of aphakic IOLs has basically taken three directions recently, based on presentations here.

First, there is an attempt to correct the positive spherical aberrations of the aphakic eye through a lens with negative spherical aberration, such as Pharmacia’s Tecnis. The positive results of this novel lens design on optical quality and contrast sensitivity were presented by Roberto Bellucci, MD, at the national meeting of the Italian cataract and refractive surgery association (AICCER), which was held in conjunction with the ESCRS congress.

Second, lens technology with the potential of restoring accommodation is being explored. This option can be applied to both cataract surgery and refractive lensectomy. The two accommodative IOLs currently available, the C&C Vision CrystaLens and the Humanoptics 1CU are gaining increasing popularity as positive results emerge with increasingly long follow-up, speakers here said.

The third and most recent trend is that of lenses that can be injected through a 1.5-mm incision. This extreme foldability is achieved through a concentric optic design and thermosensitivity in the ThinOptX IOL and through the special shape and suppleness of the material in the AcriSmart lens by Acri.Tec. Both models have been implanted by Matteo Piovella, MD. He said he was equally satisfied by the results with the two lens models.

“Now that lens technology has achieved the goal of micro-sizing, we are obliged to improve bimanual surgical techniques and instrumentation, which at the moment are not yet up to the standards of these new implants,” Dr. Piovella said.

Wavefront achievements

Wavefront technology in its various applications was discussed throughout the meeting. Ophthalmologists are demonstrating rapidly growing interest in customized ablation, as it becomes increasingly clear that addressing optical aberrations can help to obtain high-quality refractive correction.

Three aspects of wavefront technology were explored: wavefront-guided customized ablation, topography-supported customized ablation for the correction of aberrations induced by laser surgery, and wavefront analysis of the visual quality following refractive surgery, both with laser ablation and phakic IOL implantation.

The results of different types of software for ablation planning, old and new, were presented, in combination with various lasers. In both LASIK and photorefractive keratectomy, presenters said wavefront-guided systems were found to give better refractive correction, better quality of vision and more accurate results, with a lower increase in fourth-order spherical aberration and a reduction of third-order aberrations (coma).

The study with the largest number of eyes was presented by Stephen Slade, MD, who showed the results of LASIK with Zyoptix (Bausch & Lomb) in 340 eyes from three investigation sites in the United States.

Refractive surgical complications were shown to be fully or partly correctable by topography-supported customized ablation programs like TOSCA (Carl Zeiss Meditec), said Ioannis Pallikaris, MD. He said he uses TOSCA with the Meditec MEL-70 flying-spot laser.

“It is not the perfect and ultimate solution, but it is at present the best we can get for correcting surgically induced aberrations which so badly affect visual quality,” Dr. Pallikaris said.

Numerous papers at the meeting suggested that aberrometry will become the standard method of evaluating optical quality in eyes after cataract surgery and all refractive surgery procedures.

To evaluate the outcomes of the Pharmacia Tecnis in comparison with standard IOLs, Dr. Bellucci measured the point spread function and the modulation transfer function with a Shack-Hartmann aberrometer from Topcon. Similarly, Helgason Göran, MD, said he used the Bausch & Lomb Zywave system to assess the effects on higher-order aberrations of the STAAR ICL and the CIBA Vision PRL.

Several types of foldable IOLs implanted after phacoemulsification were also evaluated. In all cases, the conclusion was that higher-order aberration changes occur in all types of ocular surgery, and that lens material and design do have an influence on the amount of postoperative aberrations, speakers said.

In a final message at the end of the meeting, Dr. Pallikaris pointed out that, in the future, customized ablation will have to be even more customized to the patient, taking into account age, profession, social life and daily habits.

“Since aberrations are different in an eye looking far or near, we’ll have to decide in each case what kind of correction we want, and whether we want to correct the aberrations at far, near or intermediate,” he said.

Eye tracking needs improvements

An entire symposium during the meeting was dedicated to eye-tracking systems. A series of weak points, as well as some novel options, were discussed. The conclusion reached was that eye tracking is still a technology in development.

Patient fixation, as well as eye, head and body movements, remain out of the control of the surgeon and of whatever sophisticated technology in use during surgery, speakers noted.

Marie-José Tassignon, MD, raised the question of unbalanced ocular motility, a problem that she said is often ignored by surgeons.

“We all have a dominant eye, and some patients have an absolute dominant eye. Serious cases of decentration are often seen in these patients, because the nondominant eye has fixation problems and rotates into abnormal positions during surgery,” she said.

A magnetic system for preoperative evaluation of involuntary eye movements was presented by J.L. Bour, MD. But are eye-tracking systems up to the task of compensating for these movements intraoperatively? Dr. Bour said that, in his opinion, “video-based systems should be improved by increasing sample frequency. Systems based on infrared laser light have a better possibility, because they can achieve high sample frequency from 200 Hz to 500 Hz. However, if eye rotation exceeds 10°, which is about 1.5 mm, then all eye trackers are unreliable, and we should just stop the laser.”

If parallax errors are more often induced by eye-tracking systems that center on the pupil, according to some surgeons, centration on the visual axis is not devoid of problems. The latest developments in customized ablation have created the necessity of aligning topography, aberrometry and laser, which all may have different methods of centration.

“The alignment capability of our tracking systems must be improved,” said José Güell, MD. “We still are a long way from what we need.”

Refractive surgery complications

Complications of refractive surgery and their legal implications were also discussed at the meeting, with a focus on prevention.

Pupil-related night vision disturbances are often preventable because patients at high risk for these symptoms are identifiable, said Emanuel Rosen, FCOphth. He strongly recommended the use of a digital pupillometer, such as the one manufactured by Procyon, because it provides dynamic multiple measurements and therefore greater accuracy.

Other presentations dealt with ways of avoiding decentration and ways of treating them if they occur. Refractive surprises and post-LASIK ectasia were also discussed.

“There are patients who don’t have keratoconus or thin corneas but still develop ectasia,” said Dan Epstein, MD. Looking at preoperative pachymetry maps of patients who developed postop ectasia, Dr. Epstein found asymmetries in corneal thickness and decentered thinner points in the cornea. These, he said, might be predictors of post-LASIK ectasia. Criteria for patient selection might therefore consider such patients unsuitable for refractive surgery, he said.

Concern about the growing number of medicolegal proceedings related to refractive surgery was expressed by both the speakers and the audience. The obligation to educate patients about possible complications, minimize the occurrence of complications and properly diagnose and manage them if they occur was stressed in many presentations.

Discussing data on medicolegal cases in Italy in recent few years, Roberto Dossi, MD, explained that the Italian Opthalmological Society has been organizing a system of legal advisory and insurance for its members.

“Professionals should not be left to deal with legal issues alone, because every single case of badly managed legal loss falls upon the entire specialty,” he said.

The initiative is proving to be successful, he said, and could be a model for similar initiatives by other national and international medical societies.