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  • Prosthetic Iris Devices: Indications, Availability, Preoperative Planning, Clinical Examples, and Implantation Tips

    Refractive Mgmt/Intervention
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    Patients with iris defects do not present very often in routine clinical practice. The average ophthalmologist may encounter only a handful of these patients in a year. But when they present, they are usually quite light- and glare-sensitive and they present a significant therapeutic challenge.



    Indications

    Patients with iris defects do not present very often in routine clinical practice. The average ophthalmologist may encounter only a handful of these patients in a year. But when they present, they are usually quite light- and glare-sensitive and they present a significant therapeutic challenge.

    Most iris defects result from penetrating and nonpenetrating trauma. Penetrating iris injuries are often associated with iris tissue loss. Many patients with significant trauma histories have other ocular injuries including corneal scars, corneal decompensation, retinal scarring, and retinal detachment histories. Another common cause of acquired aniridia is surgical trauma. Posttraumatic and postoperative aniridia is further classified as partial or complete.

    In routine clinical practice, congenital forms of aniridia are less common. Congenital forms include colobomas and hereditary aniridia. Hereditary forms of aniridia can also be partial or complete. Hereditary aniridia is often associated with corneal thinning, glaucoma, loose zonules, and poor visual potential. Current Availability of Prosthetic Iris Devices

    At this time, there are no FDA-approved artificial iris devices in the United States. While many companies have plans to enter the prosthetic iris market, only a Dutch company, Ophtec, and a German company, Morcher, have actually manufactured devices for worldwide distribution.

    Ophtec manufactures a variety of artificial iris devices, and their model 311 iris reconstruction lens is in phase 3 clinical trials in the United States. Ophtec hopes the model 311 lens will be approved by the FDA by the second or third quarter of 2008. Morcher has no plans to pursue clinical trials of its devices in the United States. Morcher implants are available on a case-by-case compassionate-use basis through the FDA.

    Preoperative Planning

    If an aniridic patient presents with a clear lens, the lens should not be sacrificed to correct an iris defect. Patients with clear lenses should be instructed to wear dark glasses or tinted contact lenses. Artificial iris contact lenses are also available.

    The most important question a surgeon asks in planning the implantation of an artificial iris device is, “Does the patient have a cataract?” If yes, and the zonules are reasonably strong, my preference is to implant 1 or 2 Morcher capsule tension ring (CTR) devices to recreate an artificial iris. If the iris defect is sectoral, a sectoral or coloboma ring can be implanted. If the defect extends 360 degrees, 2 or more CTR devices can be implanted to reconstruct an entire iris, as shown in Figure 1. The most common devices I implant are the 96F coloboma ring and the 50F pupil reconstruction ring. Two 50F rings are needed to reconstruct a complete iris.

    Courtesy Kevin M. Miller, MD.
    Figure 1. Morcher 50D ring being implanted on top of an IOL.

    Currently available Morcher sulcus implants don't have the necessary radial dimension to cover the edge of a lens implant. Best results with Morcher implants are obtained when they are implanted inside the capsular bag.

    If a patient is aphakic or pseudophakic and the capsular bag is violated, I prefer to implant an iris reconstruction lens rather than a CTR. The Morcher 67B iris reconstruction lens, shown in Figure 2, is preferred for patients with dark-brown irises. The brown Ophtec 311 iris reconstruction lens is a good choice for patients with light brown or brown-green irises. I prefer the green Ophtec for patients with green or greenish-brown irises, and reserve the blue Ophtec 311 for patients with very light blue irises, such as those we see in albinos. Ophthalmologists should implant the blue Ophtec 311 with caution because it is very light and reflective. All 3 Ophtec model 311 devices are shown in Figure 3.

    Used, with permission, from www.morcher.com.
    Figure 2. Specifications for the Morcher 67B iris reconstruction lens.

    Courtesy Kevin M. Miller, MD and Ophtec USA.
    Figure 3. Ophtec 311 iris reconstruction lenses.
     

    Clinical Examples

    A few clinical examples will serve to illustrate how the different devices can be used to compensate for both small and large iris defects.

    The Morcher 96F ring is useful for treating small sectoral defects of the iris. The patient in Figure 4 (left) fell and hit his left eye against a stake in the ground as a child, rupturing his globe and causing a significant pupil deformity. The eye developed amblyopia and a dense cataract ensued. As an adult, the patient came to me complaining of decreased peripheral vision and difficulty flying a private airplane. If standard cataract surgery had been performed and a normal lens implanted, the patient would have had significant glare from light entering the eye outside the edge of the optic.

    Courtesy Kevin M. Miller, MD.
    Figure 4. Patient with corectopia, some iris tissue loss, and a dense cataract.

    To address the problem, the scar was released from the limbus area and the pupil centrally stretched. To cover the secotral iris defect created by surgery, a Morcher 96F ring was implanted inside the capsular bag in front of the lens implant. Figure 4 (right) shows the postoperative result. The patient’s visual acuity improved from 20/200 to 20/70 uncorrected, better than he remembers, and his peripheral vision was restored.

    If a larger defect in the iris is present, or the iris is completely missing but the lens and zonules are intact, a different type of iris reconstruction capsule tension ring can be implanted. Figure 5 (left) shows the clinical appearance of an eye with partial congenital aniridia. This patient had a strong family history of congenital aniridia. For this patient, 2 Morcher 50D aniridia rings were implanted in the capsular bag. My ring of choice now is the 50F. Two overlapping rings were placed in the capsular bag on top of the lens implant. The postoperative appearance is shown in Figure 5 (middle), and a slit lamp retro illumination view is shown in Figure 5 (right). The 50F design eliminates the manipulation holes at the pupil margin shown in the retro-illumination photograph. These overlapping occluder rings hide the edge of an implant so that it does not produce glare symptoms.

    Courtesy Kevin M. Miller, MD.
    Figure 5. Patient with partial and asymmetric aniridia.

    If a patient is aphakic, pseudophakic, or has a visually significant cataract, and the iris is dark brown, my preference is to implant a Morcher 67B iris reconstruction lens. This device has a 3-mm optic and a black artificial iris. Suture-fixation eyelets on the haptics can be used to suture-fixate the device to the sclera.

    The patient in Figure 6 (left) suffered complete traumatic aniridia in a motor vehicle accident several years before, presenting with a dense cortical and posterior subcapsular cataract. His irises were dark brown. As can be seen in the retro illumination photographs in Figure 6 (right), the patient had significant cause for light and glare sensitivity. Phacoemulsification and intraocular lens (IOL) implantation were performed. The patient’s foldable lens implant was removed and replaced with a Morcher 67B iris reconstruction lens.

    Courtesy Kevin M. Miller, MD
    Figure 6. Patient who is completely aniridic in his right eye.

    Cosmetic outcomes of surgery are important to most patients; this is particularly true of patients who suffer from partial or complete aniridia. If a patient has a blue or green iris, it is generally safe to implant a brown Ophtec 311 iris reconstruction lens. The brown implant is ideal for patients who have light brown irises. If there is sufficient capsule support or a patient is pseudophakic, the Ophtec 311 can be implanted without suture fixation.

    The patient in Figure 7 (top left) had cataract surgery that resulted in inferior iris trauma, posterior synechia, lens capture, and significant light and glare sensitivity. The dislocated lens was removed, the posterior synechiae were broken, and a brown Ophtec 311 iris reconstruction lens was implanted in its place. This lens requires a 9.5-10 mm incision for implantation. The lens in this case was simply placed in the ciliary sulcus between the remaining anterior capsule and the iris, as shown in Figure 7 (top right). Close-up photographs of the patient before and after surgery reveal a satisfactory cosmetic result, as shown in Figures 7 (bottom left and right).

    Courtesy Kevin M. Miller, MD.
    Figure 7. Patient who had traumatic cataract surgery

    Ophtec 311 iris reconstruction lenses can be implanted in piggyback fashion if the first lens is securely in the capsular bag and a large iris defect is present. Residual spherical refractive errors can also be corrected. Figure 8 (top left) shows the appearance of an eye that was moderately hyperopic prior to cataract surgery. Anterior capsule opacification is shown in Figure 8 (top middle). A lens was successfully implanted in the capsular bag, but the iris was damaged in the processes and the eye turned out hyperopic. At the time of reoperation, the anterior capsulotomy was enlarged and a green Ophtec 311 iris reconstruction lens was implanted in piggyback fashion without suture fixation, as shown in Figure 8 (top right). The cosmetic outcome on the patient’s appearance is shown in Figure 8 (bottom left and right).

    Figure 8. Patient with a blue-green iris and a shallow anterior chamber

    Finally, many patients present with significant ocular comorbidity besides partial or complete aniridia. Blunt trauma to the eye of one patient, shown in Figure 9 (top left), resulted in complete expulsion of the iris and lens, corneal decompensation, retinal detachment, and macular scarring. Corneal transplantation was necessary to rehabilitate this patient’s eye. At the time of transplantation, a blue Ophtec 311 iris reconstruction lens was sutured into the ciliary sulcus. The postoperative result is shown in Figure 9 (top right). Before and after full-face photos are shown in Figure 9 (bottom left and right). The patient has a postoperative esotropia following scleral buckle repair of a retinal detachment.

    Courtesy Kevin M. Miller, MD.
    Figure 9. Patient with traumatic globe rupture

    As can be seen from all the examples above, perfect cosmetic results are difficult to achieve. Nevertheless, most patients report significant improvement in light and glare sensitivity and improvement in functional vision following implantation of these prosthetic iris devices. Implantation Tips

    A few practical tips make implantation of artificial iris devices easier. First, it is easier to implant Morcher 96F coloboma implants if the ring portion of the CTR is implanted first and the occluder paddle is dialed in last.

    When implanting two Morcher devices in the capsular bag, it is helpful to use high magnification to visualize the capsulorrhexis. Staining the capsular bag with trypan blue dye is also helpful, even if the cataract is not dense. It can be difficult to visualize the capsulorrhexis once a lens implant and one ring implant are already inside the bag.

    The lens implant should always be placed behind Morcher implants to avoid the problem of lens-induced visual disturbances or dysphotopsias. Some surgeons find it easier to inject the lens implant through the opening in the Morcher implants rather than implant the IOL first and the Morcher rings second.

    Extreme caution should be exercised in implanting blue Ophtec 311 iris reconstruction lenses. The blue device is very light in color and very reflective. It can be seen from across a room, and it attracts considerable attention. Brown is the safest color to implant, even if an iris is blue or green. Green looks nice in an eye that has a blue-green iris.

    When suturing Morcher 67B or Ophtec 311 implants in the ciliary sulcus, it is best to attach sutures to the eyelets away from the surgical field. This way, suture material will not get caught in the lid speculum and drape. The surgeon should always use nondissolvable sutures. 10-0 and 9-0 Prolene are the most common. Some surgeons use Gore-Tex. Prolene sutures should be trimmed long to avoid erosion through Tenon’s capsule and conjunctiva. If the sutures are trimmed short, the knots should be buried beneath scleral flaps.

    It is difficult to center iris reconstruction lenses. They can also be tilted. Decentration and/or tilt of a Morcher implant are generally unnoticeable cosmetically. Ophtec lens decentration, however, is usually obvious. The surgeon is never really certain of final implant position until the eye is closed and pressurized. If a device is decentered after closure, it prolongs surgery time to reopen the eye and repass the sutures.

    The long-term health of eyes that suffer from partial or complete aniridia depends on ocular comorbidities. The most significant determinate in my experience is whether a corneal transplant is needed. Eyes that receive simultaneous corneal transplants have mixed results, with very good and very poor outcomes. The long-term prognosis in these cases depends on the long-term health of the corneal transplant.

    Summary and Conclusion

    Patients with congenital and acquired defects of the iris remain a challenge for the ophthalmologist. Prosthetic iris devices available through Ophtec and Morcher provide the possibility of reducing light and glare sensitivity and improving visual function for these uncommon problems

    References

    1.Miller KM, Keener GT Jr. Stretch pupilloplasty for small pupil phacoemulsification.Am J Ophthalmol. 1994;117(1):107-108.
    2.Osher RH, Burk SE. Cataract surgery combined with implantation of an artificial iris.J Cataract Refract Surg. 1999;25(11):1540-1547.
    3.Burk SE, Da Mata AP, Snyder ME, Cionni RJ, Cohen JS, Osher RH. Prosthetic iris implantation for congenital, traumatic, or functional iris deficiencies.J Cataract Refract Surg. 2001;27(11):1732-1740.
    4.

    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(1):1847-1852.

    5.Miller AR, Olson MD, Miller KM. Functional and cosmetic outcomes of combined penetrating keratoplasty and Ophtec iris reconstruction lens implantation in eyes with a history of trauma.J Cataract Refract Surg. 2007;33(5):808-814.

    Author Disclosure

    Dr. Miller is an unpaid clinical investigator in the Ophtec 311 iris reconstruction lens US Food and Drug Administration clinical trial. He also holds an FDA individual device exemption (IDE) to implant and study Morcher artificial iris devices. He does not receive compensation from Morcher for this study.