February 2013

 

COVER FEATURE

 

Presbyopia

A scleral approach to presbyopia


by Vanessa Caceres EyeWorld Contributing Writer

   
Coin Scleral spacing procedure Implant

Scleral spacing procedure steps Scleral spacing procedure implant steps

Eye

Scleral procedure

Scleral spacing procedure implant position behind eyelids Source (all): Karl G. Stonecipher, M.D.

SSP Implant SSP Implant Source (all): Karl G. Stonecipher, M.D.

Procedure in Phase III FDA trial targets plano presbyopes

The expanding options for presbyopic patients in the future may include the placement of scleral implants in the eye.

Better known as PresVIEW (Refocus Group, Dallas), this scleral spacing procedure for presbyopes has been around for a while and continues to undergo review and follow up as investigators track patients in the U.S. FDA Phase III stage of PresVIEW's clinical trial.

PresVIEW involves the insertion into the eye of four olymethylmethacrylate implants about the size of a small grain of rice, according to the Refocus website. Surgeons create tunnels for the implants in the scleara with a scleratome, said Karl G. Stonecipher, M.D., medical director, TLC Laser Eye Centers, Greensboro, N.C. The scleratome used now is a lighter weight model than a previous version. Changes to the scleratome and the procedure itself have halved the time it takes to perform the procedurefrom 30-40 minutes per eye before to about 20 minutes per eye now, Dr. Stonecipher said. After the implant is inserted, U.S.-based surgeons suture the conjunctiva, while surgeons in Europe are using tissue glue, he said.

Patients receive numbing drops and anti-anxiety medication, according to the Refocus website. The patient may have some soreness and inflammation a few days after the procedure, and it takes a couple of weeks for complete healing.

The Phase III clinical trial with PresVIEW includes about 330 patients. Patients are plano presbyopes between the ages of 50 and 60 without any need for distance correction; although they may want to improve their reading vision, their best corrected distance visual acuity must be 20/20 or better. Patients' eyes are operated on three weeks apart.

The U.S. trial has reached the maximum allowed enrollment, and therefore is no longer enrolling patients; instead, investigators around the U.S. are focusing on the collection of two years of follow-up data, said Lance Kugler, M.D., Kugler Vision, and University of Nebraska Medical Center, Omaha, Neb.

The trial should be complete by July 2014, according to ClinicalTrials.gov.

So how's it working?

What is surprising to investigators is how patients in the trial are finding increased visual improvement over time, instead of great visual improvement right away that might fade with time. "It's as if to say, 'I'm giving you the gym, you build that muscle up and work it out,'" Dr. Stonecipher said, noting that 52 patients have participated at his practice. "If you look at our patients after six months, you see more of an effect than at three months. If you look at them at one year, there's a better effect than at six months. The procedure seems to continue to improve their ability to see with time," Dr. Kugler said. "Of the patients we've done, no one has worsened, and most people have improved." Some of Dr. Kugler's 30 patients no longer need reading glasses; others still use them for some tasks, he said.

"Patients have improved reading vision from the procedure," said Brian S. Boxer Wachler, M.D., director, Boxer Wachler Vision Institute, Beverly Hills. Dr. Boxer Wachler has been involved with PresVIEW since its Phase I trials; in Phase III, he has performed the procedure in 13 patients/26 eyes.

Although the results have been positive, the research still needs to show exactly what makes PresVIEW effective in target patients, Dr. Stonecipher said.

The procedure itself will have some improvements in the near future, including the previously mentioned faster surgical speed. "The company is working on the device that will make creating the tunnels a faster process than it currently is. This will make it easier for surgeons," Dr. Boxer Wachler said.

Some refinements to PresVIEW that are undergoing tests overseas may soon reach the U.S. and make the procedure more predictable, Dr. Kugler said. There is a risk of anterior segment ischemia with the procedure, Dr. Stonecipher said. However, with the use of a pupillometer, surgeons can measure the pupil as needed and eliminate the chance of such a problem occurring.

A marketplace fit

If PresVIEW's trials have positive results and the procedure is approved by the FDA, investigators envision the surgery targeting the large number of plano presbyopes in the populationand specifically, patients who want to avoid or cannot tolerate monovision and who may need particularly strong binocular vision, Dr. Kugler said.

"Right now, we don't have a great solution for plano presbyopes," Dr. Kugler said. "You look at scleral spacing and corneal inlays and other technology that's emerging. I think there will be a role for all of them, and the demand is huge."

Dr. Stonecipher also sees a role for the various presbyopic solutions, ranging from modified monovision to corneal inlays to lens-based solutions to a procedure like PresVIEW.

"I think the market will allow us to treat different factions of patients with different options," he said.

PresVIEW also fits into the ever-growing presbyopic market due to both the large population of plano presbyopes ideal for this treatment and because patients who have had previous refractive surgery are requesting presbyopic options as they age into their naturally occurring presbyopia, Dr. Stonecipher said.

Editors' note: Dr. Stonecipher has financial interests with Refocus Group. Drs. Boxer Wachler and Kugler have no financial interests related to this article.

Contact information

Boxer Wachler: 310-860-1900, bbw@boxerwachler.com
Kugler: 400-558-2211, lkugler@lasikomaha.com
Stonecipher: 336-288-8523, stonenc@aol.com

Related articles:

Monovision revisited by Erin L. Boyle EyeWorld Senior Staff Writer

Presbyopia treatment Poll size: 198

Filling a void in the spectrum of options for presbyopia correction

Presbyopia case management by Erin L. Boyle EyeWorld Senior Staff Writer

Optimizing refractive outcomes in presbyopia patients by Enette Ngoei EyeWorld Contributing Editor

A scleral approach to presbyopia A scleral approach to presbyopia
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