In treating patients who, through disease or trauma, require an iris implant, surgeons' options have always been fairly limited and not very appealing. That may change in the coming years.
Three companies have manufactured iris implants that have been used in the United States: Morcher GmbH, Ophtec BV, and Dr. Schmidt Intraocularinsen GmbH, a subsidiary of the HumanOptics Group. The newest implant (CustomFlex Artificial Iris by HumanOptics) will soon begin clinical trials.
None of these iris implants is currently approved by the Food and Drug Administration, and they can only be implanted after receiving a compassionate use exemption, which can be time-consuming. "Every time a patient needs one of these devices, we have to file 11 documents with the FDA. Then, we have to file another set of documents with the IRB," says Kevin M. Miller, MD, professor of clinical ophthalmology at Jules Stein Eye Institute and the David Geffen School of Medicine at UCLA.
Candidates for artificial iris im–plants are patients who have sustained trauma to the eye and patients with congenital aniridia. "Some trauma cases don't need an artificial iris implant," says Francis W. Price Jr., MD, in practice at Price Vision Group in Indianapolis. "We may be able to reconstruct the iris with sutures, and that's always what we try first. If that's not possible, then we go to an artificial iris implant."
Currently, none of these implants is covered by insurance. "This is a problem," Dr. Price explains. "We have argued for years that the benefit of these implants is primarily functional. If you don't have a pupil, you have disabling light sensitivity and glare as well as losing depth of focus."
He notes that this is an interesting group of patients because most of them have other eye problems. "For instance, if a patient has congenital aniridia, he or she has a high probability of also having problems with glaucoma, corneal scarring and maldevelopment of the macula so that some of these people may only have best-corrected vision of 20/200," he says. "Additionally, they often develop cataracts at an early age. These issues can complicate an FDA clinical trial, because the FDA likes to have everything clean, with nothing else going on."
Like patients with congenital aniridia, trauma patients rarely have injury to the iris without other ocular involvement. They may have retinal detachment, corneal decompensation and corneal scars, glaucoma and dislocated lenses. "One of the first things you need to do when you see one of these patients is to see what else is going on and manage the other problems," Dr. Price explains.
According to Dr. Miller, Morcher was the first company to enter this market. "The very first one out there was a modified capsular tension ring with a little black paddle on it," he says. "It was good for covering small holes in the iris. Morcher now has many devices. Most are made of black PMMA, so there is no cosmetic benefit, but they do significantly reduce glare sensitivity."
In 2008, Dr. Miller and his colleagues at UCLA published their interim results with Morcher iris diaphragms in the treatment of partial or complete aniridia.1 This single-site clinical trial was conducted to evaluate the Morcher iris diaphragm models 50D, 50F, 96S and 96F. Thirteen patients completed one year of follow-up. Patients had a median improvement in best-corrected visual acuity of two Snellen lines, which was statistically significant. They reported two adverse events: minor bleeding during a posterior synechialysis that resolved on its own, and piggyback intraocular lens decentration from worsening zonular dialysis in an eye that had a history of trauma. There was a median improvement in best-corrected glare acuity of 10 Snellen lines, which was statistically significant. Subjective daytime glare improved five questionnaire points, while night-time glare improved three points.
However, these implants are not ideal. They have two overlapping rings that must be dialed into place. "They are not overly easy to place, and the black PMMA is brittle and can break easily," says Michael E. Snyder, MD, who is in practice at the Cincinnati Eye Institute. "The 67 series has an outer diaphragm of varying proportion and a central aperture of varying proportion. They come either with or without a focusing optic."
In August, Morcher sent a letter to doctors who have implanted the devices to inform them that the FDA "will no longer provide 'compassionate use' approvals for Morcher aniridia devices. They say we are required to file for an investigational device exemption leading to a premarket approval." So, these Morcher implants are currently unavailable in the United States. However, they are still being implanted in Canada and Europe.
According to Dr. Price, two Ophtec devices have been implanted in the United States: the IPS and the Model 311 Aniridia Lens II.
The Iris Prosthetic System (IPS) is implanted in the capsular bag and provides occlusion of partial or total iris defects. It is used in combination with a posterior chamber IOL and a capsular tension ring to stabilize the capsular bag. It comes in either a 3-mm or 4-mm pupil width, and it has an overall diameter of 10.5 mm.
The 311 Aniridia Lens II is designed for scleral or sulcus fixation, depending on the clinical condition of the zonules. These implants come in brown, green and blue.
Dr. Price notes that these implants were designed for patients in the Netherlands who have very light irises. "They don't see some of the really dark irises that we see in people who are from southern Europe or who are African American, but it's still better than nothing," he says. "The haptics go out to 13.75 mm, so it's a pretty large implant. You can basically sew it into anybody's eye, and if you're careful and meticulous, you can put these in the capsular bag, which I've done a number of times. The biggest drawback is that, because the artificial iris part is 9 mm in diameter, you have to make a 10-mm incision to get it into the eye."
The Ophtec 311 is currently finishing Phase III trials, and results have not yet been published. However, preliminary Phase I results found that it can improve uncorrected visual acuity and reduce glare and photophobia in patients with partial or total absence of the iris.2 For the Phase I study, 10 lenses were placed in 10 patients at six sites. Nine of the patients had lost all or part of their iris from trauma, and one patient lacked iris pigmentation due to congenital albinism. All eyes experienced improvement in uncorrected visual acuity after implantation.
Photophobia was reduced in all nine eyes that experienced photophobia preoperatively, and glare was reduced in all six eyes that experienced glare preoperatively.
"This study has been going on for a number of years in hundreds of patients, and the results are really spectacular," Dr. Price says. "Patients notice the improvement in the light sensitivity and glare immediately. These people are really disabled by the lack of an iris or a large defect in the iris. Putting these artificial irises in their eyes changes their lives completely. It has been an amazing thing. The drawback of this particular lens is that it just comes in three colors that are kind of light, and the blue is a little bright. Also, they are flat, so there is no texture to them."
HumanOptics/Dr. Schmidt Intraocularisen
In contrast, the CustomFlex Artificial Iris, which will soon begin clinical trials in the United States, has a realistic, natural-looking appearance and can be implanted through a 3.2-mm incision.
The device is made of silicone and has a textured anterior surface and an opaque black posterior surface. "The anterior surface is made to match a photograph taken of the fellow iris," says Dr. Snyder. "It comes in a 12.8-mm outer diameter aperture and a 2.75-mm inner aperture and is available in two versions. One has an imbedded polyester mesh, and the other doesn't. The one with the mesh has a greater ability to hold sutures. It is also a little bit stiffer, so it is a little bit harder to manipulate within the anterior chamber. Currently, these are available only under compassionate use device exemptions."
Dr. Snyder notes that the device is so realistic that ophthalmologists can be fooled into believing it's a natural iris. "It's head and shoulders above anything else out there," he says. "It looks awfully natural. Even among the investigators I have recruited to be part of this study, even after they have seen my videos and the pictures, they are surprised by how real it looks. The first time I put one in an eye-bank eye, after inserting it, one of my retinal colleagues was walking by the room, and I asked him to take a look at it. He asked what he was supposed to be looking at. It looked that real. It is truly amazing."
Samuel Masket, MD, too, calls the device "truly spectacular." Dr. Masket, who is in practice at Advanced Vision Care in Los Angeles, says, "I think ophthalmologists could be fooled into thinking it's a normal iris even at the slit-lamp it is so spectacular in its workmanship."
According to Dr. Miller, after a photograph is taken of the patient's normal iris, the patient approves the color match by looking in the mirror and then looking at the picture. "Then, we send those pictures off to the company, and the iris color is hand painted onto a silicone wafer that is encased in clear silicone, which provides texture," he explains. Additionally, the implant can be cut to size for further customization.
The implant is rollable/foldable and can be inserted through a 3.2-mm incision. Additionally, these implants do not have an optic, which Dr. Masket believes is an added benefit. "Because it doesn't have an optic, you can use it with any optic you choose," he says. "If the patient requires a toric lens or a multifocal lens, the surgeon still has the optic of choice. People can say that not having an optic is a disadvantage, but to me it is an advantage in that it allows the surgeon to work through small incisions and use whatever IOL or optic is most appropriate for that patient."
This device is relatively new to the United States. According to Dr. Snyder, approximately 55 have been implanted in this country so far under a compassionate use device exemption. "The protocol for the FDA clinical trial has already been submitted. It would be nice if we could get the implant to approval in a 2.5-year timeframe," he says.
1. Olson MD, Masket S, Miller KM. Interim results of a compassionate-use clinical trial of Morcher iris diaphragm implantation: Report 1. J Cataract Refract Surg 2008;34:1674-1680.
2. Price MO, Price FW Jr., Chang DF, Kelley K, Olson MD, Miller KM. Ophtec Iris Reconstruction Lens United States Clinical Trial Phase I. Ophthalmology 2004;111-1847-1852.