Clinical Evaluation of Morcher Artificial Iris Diaphragms

Clinical Evaluation of Morcher Artificial Iris Diaphragms to Treat Light and Glare Sensitivity in Partial or Complete Aniridia

The purpose of this study is to determine the safety and efficacy of Morcher iris diaphragms in the treatment of congenital and acquired aniridia. Morcher iris diaphragms are intraocular devices that are designed to provide an artificial pupil for patients suffering from partial or complete aniridia. These devices are constructed from clinical quality, ultraviolet light-absorbing, opaque black polymethylmethacrylate (PMMA). After surgical implantation, patients are monitored over the course of 1 year to measure any changes to visual acuity and improvements in light and glare sensitivity.

Aniridia is a condition in which the iris, the colored portion of the eye, is either partially or completely absent. The iris is responsible for regulating the amount of light entering the eye by adjusting the size of the pupil. Aniridia can either be a congenital condition, often a genetically-based abnormality affecting the formation of the iris, or it can be acquired by blunt trauma with or without rupture, penetrating trauma, or severe intraocular inflammation. Aniridia can also vary in the level of severity. A mild case might involve a thinner iris or iris remnant with a normal pupil. A severe case might involve complete absence of the iris or impairment of the muscles responsible for adjusting pupil size. Iris defects can occur without the loss of stromal tissue as well. In some cases, the iris pigment epithelium is missing. In other cases, holes are present in the iris or the pupil is chronically enlarged or mydriatic. People who suffer from iris defects also commonly suffer from other eye conditions. Common comorbidities include glaucoma, cataract, and nystagmus. Other structures in the eye are often affected, including the cornea, crystalline lens, zonules, and retina. Iris defects can cause severe visual disability if untreated. Common treatments for iris defects include the use of colored or tinted glasses or contact lenses to reduce the amount of light entering the eye. In this trial, several Morcher iris diaphragms are being evaluated as a potential treatment to improve the symptoms associated with aniridia and other iris defects. Morcher iris diaphragms are manufactured in Germany by Morcher GmbH [website: http:// www.morcher.com]. These devices have been utilized in Europe to treat aniridic patients for over 40 years. Additionally, these devices hold the European CE mark of conformity. When a patient is implanted with a Morcher iris device, surgery always involves additional standard of care surgical procedures. Typically, a device is implanted during cataract surgery along with an intraocular lens (IOL). Morcher devices can also be implanted during an IOL exchange with or without an anterior vitrectomy. All implantation procedures take place in an operating room under local or general anesthesia. In some cases, a Morcher iris reconstruction lens containing both an artificial iris and a lens is implanted. Also, depending on the condition of the eye, the lens and iris device may need to be sutured to the sclera, the white portion of the eye. All patients undergoing surgery are prescribed 2 different eye drops, an antibiotic and a corticosteroid. These medications are used for up to 6 weeks following implantation of the device. There are 5 postoperative follow-up visits that each patient must complete. Visits occur at specific intervals over the course of a 1-year period. At each visit, standard of care procedures are performed and, at certain time points during the follow-up interval, digital photos and endothelial cell counts are obtained. In instances where both eyes are implanted, surgery for the second eye is scheduled 6 months or more later.

aniridia, Morcher iris diaphragms, modified capsule tension ring, artificial iris, iris reconstruction lens, glare sensitivity, photophobia

This is a non-randomized, non-comparative interventional surgical series. Patients will undergo Morcher iris diaphragm implantation in their affected eye(s). After surgery, patients will complete 5 postoperative examinations. At each examination, they will be evaluated for changes in light and glare sensitivity and visual acuity. They will also be monitored for adverse reactions.

Change in Light and Glare Sensitivity as Determined by a Clinical Glare Test (Primary Efficacy Measure)

The primary efficacy measure of the study was the change in corrected distance visual acuity (CDVA) under glare conditions. A transilluminator light was held just in front of the distance corrected study eye in one of four quadrants (above, below, nasal, or temporal) to the line of sight to evoke a glare response. The direction that produced the worst CDVA was called the CDVA with glare. A ≥ 2 line improvement in Snellen CDVA with glare following Morcher device implantation was considered a positive clinical change (glare sensitivity better). A ≥ 2 line worsening of Snellen CDVA with glare following Morcher device implantation was considered a negative clinical change (glare sensitivity worse). A change of < 2 Snellen lines following Morcher device implantation was considered to be a neutral change (glare sensitivity the same).

The primary safety measure of the study was the change in best corrected distance visual acuity (CDVA) as measured using a Snellen eye chart. A ≥ 2 line improvement in Snellen CDVA following Morcher device implantation was considered a positive clinical change (visual acuity better). A ≥ 2 line worsening of Snellen CDVA following Morcher device implantation was considered a negative clinical change (visual acuity worse). A change of < 2 lines was considered to be a neutral change (visual acuity the same).

A secondary efficacy measure of the study was day time glare disability as assessed by subjective questionnaire. Glare disability was rated using a 0 to 10 scale, where 0 was considered very slight and 10 was considered very significant.

Another secondary efficacy measure of the study was night time glare disability as assessed by subjective questionnaire. Glare disability was rated using a 0 to 10 scale, where 0 was considered very slight and 10 was considered very significant.

A secondary safety measure of the study was the change in endothelial cell count. A loss of >10% of central corneal endothelial cells was considered clinically significant at the onset of the study. (Note, the 10% loss criterion was established before the 67B implant was added to the list of study devices. The 67B implant has an expected greater cell loss than that associated with the 96F, 96S, 50D, and 50F modified capsule tension rings because it requires a larger incision for implantation. Thirty one (48.4%) of the 64 patients were implanted with the 67B device.)

Another secondary safety measure of the study was the need to explant or exchange a Morcher iris diaphragm within 1 year of implantation. Explantation in < 25% of patients was considered to be clinically acceptable.

Inclusion Criteria: Patient must be 18 years old and have partial or complete aniridia. Be willing and able to comply with all follow-up requirements. Must have increased light and/or glare sensitivity or complete aniridia. Patients may be phakic, aphakic, or pseudophakic. Phakic patients will require simultaneous cataract surgery. Aphakic patients will require secondary intraocular lens implantation. Exclusion Criteria: The presence of any ocular condition that may cause complications from the surgical procedure Active ocular infection or inflammation Patients with allergies to operative and/or postoperative medications Pregnant or lactating women Persons who, in the determination of the investigator, are not competent to understand the procedure or the actions asked of them as research subjects

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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 Oct;34(10):1674-80. doi: 10.1016/j.jcrs.2008.05.048.

Date RC, Olson MD, Shah M, Masket S, Miller KM. Outcomes of a modified capsular tension ring with a single black occluder paddle for eyes with congenital and acquired iris defects: Report 2. J Cataract Refract Surg. 2015 Sep;41(9):1934-44. doi: 10.1016/j.jcrs.2015.10.001.

Miller KM, Nicoli CM, Olson MD, Shah M, Masket S. Outcomes of implantation of modified capsule tension rings with multiple black occluder paddles for eyes with congenital and acquired iris defects: Report 3. J Cataract Refract Surg. 2016 Jun;42(6):870-8. doi: 10.1016/j.jcrs.2016.03.035.

Lin SR, Miller KM. Lessons Learned from Implantation of Morcher 50D and 96S Artificial Iris Diaphragms. Case Rep Ophthalmol. 2017 Nov 23;8(3):527-534. doi: 10.1159/000484128. eCollection 2017 Sep-Dec.

Miller KM, Kuo A, Olson MD, Masket S. Safety and efficacy of black iris diaphragm intraocular lens implantation in eyes with large iris defects: Report 4. J Cataract Refract Surg. 2018 Jun;44(6):686-700. doi: 10.1016/j.jcrs.2018.03.033. Epub 2018 Jul 4.

Related article: Cataract and lost iris tissue after trauma. Cataract & Refractive Surgery Today. January 2012