Early multifocal ablation results positive

Among the highlights of the ASCRS Summer Refractive Congress were recent advances in cornea- and lens-based refractive surgery.

SEATTLE — In early results, all participants in an ongoing clinical trial of multifocal ablations have shown visual acuity improvement, according to an investigator.

Follow-up is brief and patients are few to date, but results of the U.S. clinical trial using the Visx Star S4 laser (Advanced Medical Optics) to create multifocal ablations for presbyopia correction are promising, said Colman R. Kraff, MD.

During the ASCRS Summer Refractive Congress in Seattle, Dr. Kraff described the Visx technology’s multifocal treatment design. A variable-spot, scanning, wavefront-guided technology is used to create the subtle ablation pattern to provide near and distance vision.

In the bilateral feasibility study for U.S. Food and Drug Administration premarket approval, the dominant eye receives a standard CustomVue treatment, and the nondominant eye receives the CustomVue treatment combined with the investigational presbyopic component, Dr. Kraff explained.

Colman R. Kraff

“Early postoperative results show positive outcomes,” he said. “Uncorrected distance vision, intermediate vision and near acuity in the multifocal eye has improved in all subjects. Multifocal eyes achieved 20/40 or better uncorrected near acuity in all five subjects.”

In the presbyopic correction, the central zone is steepened for near vision and the peripheral cornea is targeted for distance vision.

“We do what is called a pupil-size-dependent central zone,” Dr. Kraff said. “The peripheral zone, combined with the LASIK flap, produces an aspheric surface that expands the depth of focus.”

Iris registration is an important component for the presbyopic treatment because the multifocal ablation is pupil-dependent, he said.

“It is critical that we use iris registration to really accurately place the treatment over the pupil centroid,” Dr. Kraff said.

Cornea-based Refractive Surgery

Keratoconus treated with CK

Conductive keratoplasty can be a viable option to treat keratoconus, said Helen K. Wu, MD.

She presented a case study of a 40-year-old man who had mild to moderate keratoconus and underwent CK to treat it.

The patient had significant surface disease due to rosacea blepharitis that had been treated with multiple modalities by many practitioners, she explained.

The patient was also contact lens intolerant and a high myope with high astigmatism; he did not want to undergo Intacs placement or penetrating keratoplasty.

His uncorrected visual acuity was 20/200 in the right eye and 20/50 in the left eye. His best corrected visual acuity was 20/40 in the right eye and 20/25 in the left eye.

Dr. Wu used CK, placing five spots on the apex of the cone, outside the pupillary border, to flatten the cone based on the elevation map.

“His UCVA improved from 20/200 to 20/50 on the first postoperative day, and he later regressed back to 20/200. He was able to wear a toric soft contact lens with a BCVA of 20/30 in his right eye at 1 month postop,” she said.

“Early results with standard CK technique show regression that is significant after a year, but the LightTouch technique may afford better results and possibly could be used in combination with Intacs,” she said.

Pre-LASIK cyclosporine for dry eye

A preoperative regimen of cyclosporine may enhance clinical outcomes for both normal and dry eye patients undergoing LASIK treatment, according to Marguerite B. McDonald, MD.

“Dry eye after LASIK is actually the most common complaint. This has been documented by many authors,” she said. “At this point in time we are treating dry eye in LASIK with unpreserved artificial tears, gels, ointment at night, punctal plugs, nutritional supplements, wraparound goggles, and most recently we have investigated cyclosporine.”

Dr. McDonald and colleagues in New Orleans conducted a prospective study in which eyes were treated with cyclosporine 0.05% for 1 month before refractive surgery. The study included 42 eyes of 21 patients with moderate to severe dry eyes. They were randomized into two treatment groups before LASIK – those treated with unpreserved artificial tears and those treated with cyclosporine.

“The cyclosporine group was significantly closer to its intended refractive target than the unpreserved tear group at both 3 months and 6 months, and that was highly statistically significant,” she said.

Intracorneal lenses for presbyopia

Intracorneal lenses may present promising treatment options for emmetropic presbyopic patients, according to Richard L. Lindstrom, MD.

Richard L. Lindstrom

Dr. Lindstrom reported early clinical outcomes with small-diameter intracorneal lenses during the conference.

“There are a lot of emmetropic presbyopes,” Dr. Lindstrom said. “A lot of patients can be treated with [conductive keratoplasty] or LASIK monovision, and some of them do well with that, but a lot of patients don’t want to give up that distance to get the near.”

Dr. Lindstrom said the Acufocus is about to begin U.S. clinical trials. Preliminary trials began in Mexico in 2003.

The Acufocus implant is an ultrathin donut-shaped disc that uses a small-aperture principle. After the correction of ametropia with LASIK, the device is implanted under the LASIK flap while the flap is still lifted, for the purpose of improving near vision.

Lens-based Refractive Surgery

Capsule contraction with accommodating IOL

Harvey L. Carter, MD, described capsule contraction syndrome following accommodating IOL implantation at the ASCRS Summer Refractive Congress. Image: Stiglich JM, OSN

A small number of cases of capsule contraction syndrome have been reported after the first 25,000 implants of the eyeonics crystalens, according to Harvey L. Carter, MD.

In the clinical trial data on 500 eyes submitted to the Food and Drug Administration for premarket approval of the accommodating IOL, no incidence of capsule contraction syndrome was reported, Dr. Carter said.

The crystalens, designed to provide a continuous range of vision from distance through intermediate to near, has been approved for marketing in the United States since 2003 for patients undergoing cataract surgery and for the correction of presbyopia.

Dr. Carter said he was the first surgeon to encounter a case of capsule contraction syndrome (CCS) following crystalens implantation. Prior to this report of 57 cases in 25,000 implants, eyeonics said it had been made aware of 30 cases of CCS among the first 13,000 implants.

“So we are seeing roughly the same rate of incidence,” Dr. Carter said.

He said the onset of symptoms occurs between 1 and 7 months postoperatively and seems more common in patients less than 60 years old, but CCS has been seen “in virtually all age groups.” He noted that most of the patients in the FDA trial were older than 60 years and had cataract.

More about this syndrome and how to avoid it will appear in an upcoming issue of Ocular Surgery News.

Shallow chamber after ICL

A number of conditions can produce a shallow anterior chamber after implantation of a posterior chamber phakic IOL, and each must be treated differently, said Stephen S. Bylsma, MD.

Dr. Bylsma presented case studies to differentiate the conditions that can cause a shallow chamber after implantation of the STAAR Visian ICL.

Among the conditions he discussed were pupillary block glaucoma, oversized ICL vault with angle-closure glaucoma, wound leak, retained viscoelastic syndrome and malignant glaucoma. Correct treatment for these conditions requires accurate diagnosis, he said.

Of some concern for ophthalmologists is how to recognize an ICL vault caused by high pressure, he said.

“It is important to be ready with pupillary block and be able to recognize it as opposed to a high vault,” Dr. Bylsma said. “The diagnostic maneuver is to dilate the pupil. If you dilate the pupil, if it is pupillary block, the vault will go down.”

Phakic anterior chamber IOL

A phakic anterior chamber IOL has shown a low rate of endothelial cell loss in clinical trials to date, said Stephen S. Lane, MD.

Dr. Lane presented the mean outcomes in his implantations of Alcon’s anterior chamber phakic lens, which he said is in an early phase of clinical trials.

“We have to count endothelial cells obviously for clinical trials. To date, I have been able to place 14 of these lenses,” he said. “At a 4-month period of time our average [endothelial cell loss] was 2%.”

Dual-optic accommodating IOL

A dual-optic accommodating IOL was found to be “safe and stable,” according to one investigator’s feasibility study in a small number of eyes.

Ivan L. Ossma-Gomez, MD, MPH, reported that early postoperative data from eyes implanted with Visiogen’s Synchrony IOL showed that uncorrected vision improved in all cases.

Dr. Ossma-Gomez reported on 28 eyes implanted with the accommodative IOL for which he had at least 12 months follow-up. Early results indicate that 82% of eyes achieved 20/40 or better uncorrected distance visual acuity, and 100% achieved 20/40 or better uncorrected near visual acuity.

“This is a promising technology. It is safe and stable over time in the first 2 years with accommodative amplitudes of over 2.75 D as can be measured at this time,” he said.

For Your Information:

• Joan-Marie Stiglich, ELS, is Editor in Chief of Ocular Surgery News. Daniele Cruz is an OSN Staff Writer who covers all aspects of ophthalmology.