Prosthetic Iris Devices

From EyeWiki


Disease Entity

Prosthetic Iris Devices

Background

The first Prosthetic Iris Device was implanted by Dr. Choyce in 1956. It was intended to fill iris defects in patient suffering from traumatic iris defects, congenital aniridia, iris coloboma, herpetic iris atrophy, surgical iris loss, or ocular albinism among others in order to restore some of the functions of the iris. The iris acts as a diaphragm regulating the amount of light entering the eye; for instance, the amount of light entering an aniridic eye (limbal diameter 12.0 mm) is about 4-fold greater than the amount of light entering a 6.0 mm pupil. It also promotes depth of focus and limits spherical and chromatic aberrations.

Types of devices

Traditionally, there are 3 types of prosthetic iris devices:

  • Iris lens diaphragm
  • Endocapsular tension ring with fins and the
  • Costumized artificial iris such as CustomFlex from HumanOptics.

Outcomes

Burk et al, in a prospective case series of patient with iris defects who underwent prosthetic iris device implantation, reported that 79% of patients had improvement in their visual acuity and 96% reported reduction in glare. [1]

Advances

In recent years, new prosthetic iris devices have become available in the market to improve cosmesis. These devises are designed to be implanted in the anterior chamber infront of the natural iris.

Complications

Many authors have reported cases where the prosthetic iris device has lead to complications requiring explantation. Anderson et al. reported 2 cases that lead to severe complications such as hyphema, glaucoma that required explantation and other surgeries like trabeculectomy to control glaucoma. [2]Arthur et al reported a case of uveitis glaucoma hyphema syndrome and corneal decompensation that followed the implantation of the device. [3] Hoguet et al published a case series of 14 eyes who had a cosmetic iris implant, it showed that the most common complications included uveitis, glaucoma, corneal edema, and decreased visual acuity. [4]

Pathophysiology

In cases of cosmetic iris implants, corneal decompensation may be secondary to trauma to the endothelium during implantation. The implant comes in close proximity to the iris leading to frequent rubbing that releases pigment and results in pigment dispersion and glaucoma. It may also impinge on the trabecular meshwork raising the intraocular pressure. Castanera et al examined some of the implants using scanning electron microscopy and noted that the surface of the implant is very irregular and rubs on the iris.[5]

Physical examination

Prosthetic Iris device may be present in the anterior chamber or in the sulcus or bag depending on the type.

Signs

Anterior chamber reaction, flare and corneal decompensation as well as glaucoma may be present.

Symptoms

The patient may report blurring in vision.

Management of complications

Each secondary complication needs to be addressed. However the first step is explantation. This surgery requires cutting the implant into pieces after using viscocohesive material. Arjmand et al posted a video that shows a certain technique for explantation of cosmetic iris devices.[6]

References

  1. Burk SE, Da Mata A., 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).
  2. Anderson J, Grippo T, Sbeity Z, Ritch R. Serious complications of cosmetic NewColorIris implantation. Acta Ophthalmol., 2010. 88: p. 700-704.
  3. Arthur SN, Wright M., Kramarevsky N, Kaufman SC, Grajewski AL, Uveitis- glaucoma-hyphema syndrome and corneal decompensation in association with cosmetic iris implants. Am J Ophthalmol 2009. 148: p. 790-3.
  4. Hoguet A, R.D., Koplin R, Wu E, Raviv T, Aljian J, Seedor J, Serious ocular complications of cosmetic iris implants in 14 eyes. J Cataract Refract Surg, 2012. 38(3): p. 387-93.
  5. Castanera F, Fuantez Paez G., Ten P, Pinalla B, Guevara O, Scanning electron microscopy of explanted cosmetic iris implants. Clin Experiment Ophthalmol, 2010. 38(6): p. 648-51.
  6. Arjmand P, Gooi P., Ahmed I., Surgical technique for explantation of cosmetic anterior chamber iris implants. Cataract Refract Surg, 2015. 41: p. 18-22.
  1. Sathish Srinivasan, Ting D., Snyder M., Prasad S., Koch H., Prosthetic iris devices. Can J Ophthalmol, 2014. 49: p. 6-17.