This article is more than 5 years old. Information may no longer be current.
Implants help manage aniridic patients
Although no products are currently FDA-approved, one is in clinical trials and another has been implanted on a compassionate-use basis.
Click Here to Manage Email Alerts
Options for surgical management of patients with traumatic or congenital aniridia are few, but several implants now offer hope for patients with the condition. Though no implants currently have regulatory approval in the United States, one is now in clinical trials and others have been implanted on a compassionate-use basis.
|
|
The Ophtec Aniridia Lens (Ophtec USA) recently began a clinical trial for Food and Drug Administration approval. The first implant in the trial was performed last month by Francis W. Price Jr., MD.
According to the company, this is the first multicenter study of an implantable artificial iris for FDA approval. Sources agree the low incidence of patients suffering from such iris defects is a main reason device manufacturers have not previously sought FDA approvals.
“It’s not a huge problem, but in any given area there are a few people that have this. And those people are severely limited,” said Dr. Price, a corneal, refractive and cataract surgeon in Indianapolis and lead investigator involved in Ophtec’s trial.
“I think we are all very thankful to the FDA for working with Ophtec to allow us to do this study, because it’s not something that anyone is really going to get rich on. It’s really tough for companies to justify doing studies like this if only a small group of patients are going to be treated. But it is a group of people who are fairly desperate for something to help them,” Dr. Price said.
Another surgical option for aniridic patients has been implants manufactured by Morcher GmbH, of Stuttgart, Germany. Several models of artificial iris from this company have been made available to surgeons through compassionate-use exemptions, which are granted on a case-by-case basis by the FDA.
Hillard Welch, the U.S. representative for Morcher GmbH, told Ocular Surgery News the FDA has allowed surgeons to obtain Morcher’s implants under emergency use or compassionate use regulations. A surgeon wishing to use Morcher’s aniridic devices can submit a request to the FDA explaining why he or she feels the device is the most satisfactory solution to the patient’s problem.
Mr. Welch said the process is “strictly between the surgeon and the FDA,” and Morcher is not involved in the request. Once the surgeon receives approval, the FDA notifies the company and the manufacturer can supply the implant under that individual letter of authorization.
According to Mr. Welch, Morcher would like FDA approval for their aniridic devices.
“However, under the statutory regulations governing the FDA, the FDA can not summarily approve the devices. There has to be documentation, and this is something that will only be demonstrated after sufficient years of use,” he said.
There is some question as to whether the Morcher implants would remain available for U.S. compassionate use if Ophtec’s device gains approval. A spokeswoman in the FDA’s ophthalmic device branch said that it would depend on how well suited each device was for use in each individual case.
Ophtec trial
Ophtec USA announced June 25 that it received an investigational device exemption (IDE) from the FDA to begin clinical trials of the company’s iris reconstruction IOL for treating congenital or traumatic aniridia.
Rick McCarley, president and chief executive officer of Ophtec USA, said in a company statement, “Until now, surgeons needing these custom implants for their patients were required to undertake the lengthy process of obtaining case-by-case compassionate use approvals from institutional review boards and the FDA. Devices obtained under compassionate use do not provide for the collection and analysis of multicenter data to support marketing approval. Therefore, valuable data were being lost.”
Dr. Price said the trial will initially include five sites. Data received from those centers will then be submitted to the FDA. Approval will allow expansion of the trial to additional centers.
The trial will gather data on the use of Ophtec’s iris reconstruction IOL in patients with congenital or traumatic aniridia.
“In most studies, you are trying to get something to market. But I think for most of the physicians we just have been looking for a way to do this, to have access,” Dr. Price said. “This is a situation where there is a small group of people who are severely limited by not having irides.”
The Ophtec device is a PMMA implant composed of a central 4-mm optic for correction of aphakia. From the optic out to 9 mm, the implant has an opaque plastic ring to simulate the missing iris. The two haptics have eyelets at each end for fixation with polypropylene sutures in the absence of a capsule.
“If a capsule is not present, you can just place it in the sulcus,” Dr. Price said.
The lens is inserted with forceps through about a 9.5-mm limbal incision.
Dr. Price said many patients with congenital aniridia have problems with retinal development in addition to iris defects. Patients with traumatic aniridia can also have scarring of the cornea.
“Some congenital aniridia patients can have good vision, and some of them will have relatively poor visual acuities, no matter what you do,” Dr. Price said.
“You might say that these are a fairly desperate group of patients. They need something done, but they are not like the average guy off the street. Each case is different. As a group, you don’t really know what to expect. When you implant a normal IOL, most of the people you implant can be expected to achieve 20/20 vision. A lot of the eyes that we are operating on, we don’t ever expect them to achieve 20/20 because these aren’t normal eyes,” he said.
Dr. Price has been using the Ophtec lens on a compassionate basis for the past 4 years. He said he has not experienced any problems with the device.
Aniridia-Ring
Scott E. Burk, MD, PhD, a cataract surgeon with the Cincinnati Eye Institute, told Ocular Surgery News there have been only about 55 cases of aniridia referred to his center in the past 2.5 years.
“To date at the Cincinnati Eye Institute, we have used primarily the Morcher GmbH Aniridia-Ring Type 50 C,” he said. The Type 50 C is a black PMMA ring with a 10.75-mm diameter.
Dr. Burk said the ring-type prosthetic iris implants can stabilize the capsular bag.
“They work as an endocapsular ring because that’s their basic design,” he said. “For anyone who has a capsule, I think endocapsular is better than having the sutured, large-style lens. Endocapsular placements don’t have any movement and you don’t have the risks of glaucoma and prolonged inflammation, which have been reported in some cases,” he said.
“Plus, you don’t have such a large incision,” he added. “With the large lens implants, you have to implant through about a 10.5-mm incision.”
Dr. Burk said he would consider using an implant in cases in which there is greater than a few clock hours of iris loss, “or else we may not even implant a device. Sometimes people with about 3 clock hours of [iris] loss can be sutured.”
Dr. Burk presented on his experience using the Aniridia-Ring at the American Society of Cataract and Refractive Surgery meeting in Philadelphia. He said management of aniridic patients can be difficult due to underlying problems limiting visual acuity. Common complaints include glare and photophobia.
Dr. Burk said prosthetic iris implants can reduce the pupil radius by a factor of two and can reduce the pupil area by a factor of four. “This results in blocking 75% of the stray light entering the eye,” he said.
Implantation
Dr. Burk said a number of congenital aniridics have thin, weak capsules that leave them susceptible to capsular tears and make a capsulorrhexis very difficult.
In cases of congenital aniridia, Dr. Burk said he feels a capsular dye should always be used during capsulorrhexis.
“It really helps to highlight the location of the capsule. The rhexis is not normal; it proceeds in a very fragile manner. The capsular dye will help you follow that rhexis around.
“You also have to be careful to not bump the edge of the rhexis with any intraocular instruments. Things you might get away with in a normal capsule, in an aniridic capsule you can split it. That makes things a lot more difficult,” Dr. Burk said.
According to Dr. Burk, if the anterior capsule is intact, then phacoemulsification can usually proceed normally. Implantation of the prosthetic iris rings then follows.
Two rings are gently rotated into the capsular bag.
“Be careful not to place too much torque on the ring because the black PMMA is somewhat brittle and will fracture if bent too far,” Dr. Burk said.
The second ring is rotated so the fins on each ring interdigitate. An IOL is then placed in the capsular bag.
Dr. Burk said he uses the Type 50 C in most of the aniridia cases he sees. The 50 C can be implanted through a 3-mm to 3.2-mm incision.
“It makes your life a little easier if you make it 3.2 mm. There’s just a little more flexibility in terms of getting it into the capsular bag where you want it,” he said.
Other than fractured implants, a problem Dr. Burk experienced early in the learning curve using the device, he has not had any complications.
For Your Information:
- Francis W. Price Jr., MD, can be reached at Price Vision Group, 9002 N. Meridian St., Suite 100, Indianapolis, IN 46260; (800) 317-3937; fax: (317) 844-5590.
- Scott E. Burk, MD, can be reached at the Cincinnati Eye Institute, 10494 Montgomery Road, Cincinnati, OH 45242; (513) 984-5133; fax: (513) 984-4240.
- Hillard Welch, U.S. representative for Morcher GmbH, can be reached at 334 Annabelle Road, Centerville, MA 02632-2402; (508) 771-6777; fax: (508) 775-9051.
- Rick McCarley, president and CEO of Ophtec USA Inc., can be reached at 6421 Congress Ave., Suite 112, Boca Raton, FL 33487; (561) 989-8767; fax: (561) 989-9744; e-mail: ophtecusa@aol.com; Web site: www.ophtec.com.
Reference:
- Morcher GmbH, manufacturer of the Aniridia-Ring Type 50 C, can be reached at Kapuzinerweg 12, 70374 Stuttgart, Germany; (49) 711-95320-0; fax: (49) 711-95320-80; e-mail: info@morcher.com.
- Ophtec USA, manufacturer of the Iris Reconstruction IOL, can be reached at 6421 Congress Ave., Suite 112, Boca Raton, FL 33487; (561) 989-8767; fax: (561) 989-9744; e-mail: ophtecusa@aol.com; Web site: www.ophtec.com.
- A list of investigators and investigational sites involved in the trial of the Iris Reconstruction IOL is available by contacting the Clinical Research Department of Ophtec USA at (561) 989-8767.
- Price FW, Wellemeyer ML. Transscleral fixation of posterior chamber implants. J Cataract Refract Surg. 1995;20:567-573.