Iridocorneal endothelial syndrome is a group of unusual eye conditions which are associated with changes in the iris and corneal cells. The iris is the circular diaphragm that forms the colored part of the eye with the pupil in the center. The cornea is the transparent, dome-shaped surface on the front part of the eye. It contains five layers of cells. The endothelium is the innermost layer which pumps fluid out of the cornea.
ICE involves the movement of the cells from the cornea to the iris. This action can result in corneal edema (swelling) and a distorted pupil and iris. ICE affects only one eye.
ICE is also associated with glaucoma. Glaucoma occurs when the corneal cells move and prevent the fluid from draining as it should through the microscopic drainage channels of the eye. The blockage leads to intraocular pressure.
- Chandler syndrome – Affects about 50% of all Iridocorneal endothelial syndrome (ICE) cases. Corneal edema can develop into a tumor even with normal intraocular pressure (IOP). There are no iris changes at this level. The main abnormality is in the cornea.
- Progressive iris atrophy – The changes in the iris are robust and progressive.
- Iris nevus/Cogan-Reese syndrome – The anterior surface of the iris has tan nodules or pigmented lesions. There is iris atrophy (a disorder where the pupil is distorted or out of place).
Causes and Risk Factors
The causes of ICE are not fully known. It is however believed that the virus herpes simplex, may trigger ICE. The virus causes the cornea to swell. ICE is more prevalent in women than men. It also affects middle-aged people.
Signs & Symptoms
The signs of ICE may include:
- A swollen cornea
- Changes in the iris or pupil
- Signs of glaucoma
The following symptoms may be present in people with ICE:
- Pain in the eye
- Blurry vision in one eye
- Changes in the iris or pupil
The eye care professional will do a complete eye examination which includes:
- Taking a complete medical history
- Visual acuity test to determine how well an individual can see from a distance
- Checking the pupils using a flashing light to check how they dilate
- Checking peripheral vision for signs of glaucoma
- Ocular motility to see if the eyes are aligned and that the eye muscles are working well
- Tonometry to measure the pressure in the eye. High pressure is indicative of glaucoma
- A slit-lamp examination to check the front part of the eye especially for swellings of the cornea
- Dilating the eye to check on the health of the retina and optic nerve
- Other tests like specular microscopy to diagnose ICE
- A pachymeter to check for corneal edema
- Stereo disc photography and optical coherence tomography to check for glaucoma
- Gonioscopy to diagnose secondary angle-closure glaucoma
Treatment of ICE is directed towards reducing corneal edema and managing glaucoma.
There is no medical treatment for ICE. Treatment aims to manage glaucoma. Glaucoma can be treated using topical medication to reduce pressure in the eye. To reduce corneal edema and IOP, the eye doctor will prescribe aqueous suppressants such as beta-blockers, alpha agonists and carbonic anhydrase inhibitors. Also, topical hypertonic saline solutions and gels can help to reduce corneal edema by dehydrating the cornea.
Glaucoma can also be managed by surgery if IOP persists after administration of topical medications. A trabeculectomy with antifibrotic agents or an aqueous shunt (a glaucoma drainage device) can help control IOP and consequently ICE.
For intractable cases of glaucoma, a ciliary body destruction procedure is necessary. This procedure is conducted using a diode laser cyclophotocoagulation (diode CPC).
If necessary, a corneal transplant may be performed. In a penetrating keratoplasty, the surgeon replaces the cornea with a healthy cornea from a donor. Endothelial keratoplasty, popularly referred to as DSAEK or DSEK, can help improve the function of the cornea when the abnormal corneal endothelial cells are replaced.
ICE syndrome can progress to advanced glaucomatous optic neuropathy which causes extensive vision loss if it is not treated. Glaucoma tends to be severe in people with progressive iris atrophy and Cogan-Reese syndrome.
Changes in the iris such as corectopia and atrophy in patients with potential for good vision could lead to visual distortion and glare.
Glaucoma surgery may fail which can lead to loss of vision. However, in some situations, an Nd: YAG laser treatment can correct failed surgery.