Artificial iris-lens diaphragm in congenital aniridia
KAMAL JOUDA OKASHA
The International St. John Gaza Eye Center, 30 Jamal Abdel Naser St., Gaza, Palestine
Kamal Jouda Okasha — MD, PhD, Ophthalmic Consultant, Director of St. John Gaza Eye Center, tel. 00 972 (0)8 2824955, e-mail: Kam_Shahd@yahoo.com
Introduction
Aniridia is a congenital, hereditary, bilateral, extreme form of iris hypoplasia that may be associated with other ocular defects [1, 2]. Usually the patient with aniridia complains of decrease vision, glare and photophobia. There are different modalities for Treatment of photophobia which includes tinted contact lens, tinted spectacle lenses and tinted intraocular lenses (IOLs) [3]. In 2005, Pozdeyeva N.A. and coauthors described a new artificial iris-lens diaphragm in reconstructive surgery for aniridia and aphakia [4]. One of the advantages of this diaphragm is a foldable construction therefore it can be implanted through a small incision into the capsular bag. Moreover, the sulcus and scleral fixation are available too. I have been used this implant in one patient with bilateral congenital aniridia combined with cataract.
Case report
A 34-year-old patient who was presented to our center with complains of enterable glare and low vision on both eyes since childhood.
His eyes examination reveals the following:
Visual Acuity (VA):
R.E: 2/60 +7 = 6/36 L.E: 1/60 +10 = 6/60
Intraocular pressure (IOP):
R.E: 18 mm Hg. L.E: 16 mm Hg.
Slit lamp examination:
It showed on both eyes a clear cornea, a deep anterior chamber, a complete absence of the iris and anterior polar lens opacity (pic. 1).
Figure 1. Photo eye before surgery
Fundus Examination:
It was uneventful but a bilateral optic nerve hypoplasia.
A preliminary diagnosis was a bilateral aniridia with anterior polar cataract. The full medical examination for the patient was done to exclude any systemic disease.
The management plan was designed to lens aspiration with binocular implantation of the artificial iris lens diaphragm. Refraction and optical biometric data were sent to the manufacturer to order a blue implant.
Implant Descriptions
The implant was designed by Dr. Pozdeyeva (Svyatoslav Fyodorov MNTK Eye Microsurgery, Cheboksary, Russia) and cooperation with Reper-NN Company.
It consists of two parts; a 3,5 mm optical part and a 10 mm iris disk one. Although it has 5 elastic closed haptics of 3 mm in diameter with the overall diameter of 13 mm (pic. 2).
Figure 2. Model «A» of artificial iris-lens diaphragm
The diaphragm is manufactured from elastic polymer, allowing free implantation through 5, 5 mm corneoscleral tunnel incision.
Operation was undergone on the left eye on 29/01/2011, then the another one on 31/03 2011.
Surgical technique
Under a general anesthesia, the fornix based conjunctival incision was made from 11`oclock to2 o’clock. Cautery of scleral vessels was made and partial thickness scleral incision was done 3 mm at the limbus. The scleral tunnel was extended till the clear cornea. Then paracentesis was done and viscoelastic material was injected into the anterior chamber. The scleral tunnel was opened in the cornea by keratome, large capsulorexis was done by cystotome and capsulorexis forceps, lens aspiration was done using irrigation aspiration Simco cannula.
A +33 diopter iris-lens diaphragm was implanted in capsular bag using folding forceps (pic. 3). A suture was placed in the scleral wound and viscoelastic was aspirated from anterior chamber. Conjunctiva was sutured and subconjuctival injection of dexamethasone + gentamycin was done (pic. 4).
Figure 3. Iris-lens diaphragm folded before implantation using folding forceps
Figure 4. Eye with implanted with Iris-lens diaphragm at the end of the operation
Results
Both eyes were operated uneventfully, except a redial tear of anterior capsule which was noticed during the capsulorexis of the right eye. The same eye had a self-limited hyphema at the 3ed post-op day.
IOP was slightly elevated on both eyes after one week of operations and was well controlled with anti-glaucoma agents until January 2015.
IOP became uncontrolled on left eye and Ahmed valve surgery was planned and it will be done on 6 March 2015.
IOLs have normal position on both eyes. Posterior capsule opacification was occurred one year after operation and uneventful YAG laser capsulotomy was done on both eyes.
The one month follow up revealed a steady improvement of uncorrected vision to 6/24 on both eyes.
Discussion
Aniridia is a rare genetic disorder in which there is a variable degree of hypoplasia or absence of iris associated with other ocular features [1, 2].
The major diagnostic feature is congenital partial or complete hypoplasia of the iris; foveal hypoplasia with reduced visual acuity is almost always present and associates with early onset nystagmus. Other frequently associated ocular abnormalities, generally with later onset, include cataract, glaucoma and corneal opacification and vascularization secondary to limbal stem cell deficiency [5].
Several measures have been taken to overcome these symptoms which include eyelid surgery, corneal tattooing [6, 7] and implantation of artificial irides [8]. Artificial iris implants have been found to diminish visual discomfort such as photophobia.
The use of a black diaphragm intraocular lens (IOL) to correct both congenital and traumatic aniridia has been advocated [9, 10].
These lenses include the Morcher aniridia IOL type 67F and 67G, the aniridia ring type 50C and the coloboma diaphragm type 96G. They can be placed in the ciliary sulcus if there is adequate support, or are sutured trans-sclerally. However these lenses are only available in 3 standard colours in brown, green and blue and therefore manufacture cannot guarantee the perfect color match with the fellow eye. The other disadvantages of these lenses are their rigid material and necessity of large incision for implantation which increases the complications itself.
Complications reported included postoperative uveitis, secondary glaucoma, clinically significant macular edema, chronic endothelial cell loss, progression of corneal epithelial disorders and hyphema [11].
In our case study the Iris lens diaphragms were uneventfully implanted in the bag in both eyes through a small corneoscleral incision.
Glaucoma in aniridia usually occurs during the preadolescent or early adolescent years [12]. It is thought to be due to developmental abnormalities in the drainage angle of the eye, which obstruct the outflow of aqueous humor. The treatment of glaucoma associated with aniridia is difficult. Grant and Walton [13] found that 38.7% responded to medical treatment, including miotic eye drops. Of those that were responsive to medical treatment, 50.0% required oral carbonic anhydrase inhibitors.
Glaucoma has been found to be the most important complication of artificial iris. Though implantation of the iris prosthesis in the capsular bag may reduce this complication, but this requires a large capsulorexis and presents a surgical challenge.
In our patient elevated IOP was noticed after one month post-op and it was controlled by using Timoline and oral carbonic anhydrase inhibitors, however, a decision would be made to do Ahmed valve tubing because of frailer of conservative treatment.
Finally, the patient with aniridia may need lifelong regular follow-up care for the early detection of any new problems, especially glaucoma and corneal once, so that timely treatment is given [14].
REFERENCE
- Melanie Hingorani, Isabel Hanson and Veronica van Heyningen Aniridia European Journal of Human Genetics, 2012; 20: 1011-1017. doi: 10.1038/ ejhg.2012.100. published online 13 June 2012
- Lee H., Khan R., O’Keefe M. Aniridia: current pathology and management. Acta Ophthalmol, 2008; 86: 708-715.
- Robert H Osher Cataract surgery combined with implantation of an artificial iris1 J Cataract Refract Surg., 1999 Nov.; 25(11): 1540-1547
- Pozdeyeva N.A., Pashtayev N.P., Lukin V.P., Batkov Y.N. Artificial iris-lens diaphragm in reconstructive surgery for aniridia and aphakia J Cataract Refract Surg., 2005 Sep; 31(9): 1750-9.
- Melanie Hingorani, Anthony Moore, Aniridia, Includes: Isolated Aniridia, Wilms Tumor-Aniridia-Genital Anomalies-Retardation (WAGR) Syndrome, Bookshelf ID: NBK1360, 2008.
- Burris T.E., Holmes-Higgin D.K., Silvestrini T.A. Lamellar intrastromal Corneal tattoo for treating iris defects (artificial iris) Cornea, 1998; 17: 169-173
- Beekhuis W.H., Drost B.H., van der Velden Samderubun E.M. A new treatment for photophobia in posttraumatic aniridia: a case report Cornea, 1998; 17(3): 338-341
- Menezo J.L., Martinez-Costa R., Cisneros A., Desco M.C. Implantation of iris devices in congenital and traumatic aniridias: surgery solution and complications Eur J Ophthalmol., 2005; 15(4): 451-457.
- Reinhard T., Engelhardt S., Sundmacher R. Black diaphragm aniridia intraocular lens for congenital aniridia: long-term follow-up J Cataract Refract Surg, 2000; 26: 375-381
- Burk S.E., Da Mata A.P., Snyder M.E., Cionni R.J., Cohen J.S., Osher R.H. Prosthetic iris implantation for congenital, traumatic, or functional iris deficiencies J Cataract Refract Surg, 2001; 27: 1732-1740
- Sundmacher T., Reinhard T., Althaus C. Black diaphragm intraocular lens in congenital aniridia Ger J Ophthalmol, 1994; 3: 197-201
- Grant W.M., Walton D.S. Progressive changes in the angle in congenital aniridia, with development of glaucoma Trans Am Ophthalmol Soc., 1974; 72: 207-228.
- Grant W.M., Walton D.S. Progressive changes in the angle in congenital aniridia, with development of glaucoma Trans Am Ophthalmol Soc., 1974; 72: 207-228
- Jastaneiah S., Al-Rajhi A.A. Association of aniridia and dry eyes Ophthalmology, Sep 2005; 112(9): 1535-40