Iridocorneal endothelial syndrome

Overview

Iridocorneal endothelial (ICE) syndrome is a rare, progressive eye disorder that primarily affects the cornea, iris, and the drainage angle of the eye. It typically occurs in one eye (unilateral) and is more common in middle-aged women. ICE syndrome is characterized by abnormal corneal endothelial cell proliferation and migration, which leads to structural changes in the iris, corneal edema (swelling), and secondary angle-closure glaucoma. The condition encompasses a spectrum of related disorders, including Chandler syndrome, essential iris atrophy, and Cogan-Reese syndrome.

Causes

The exact cause of ICE syndrome is not fully understood, but several factors are thought to contribute:

• Abnormal endothelial cells: In ICE syndrome, corneal endothelial cells lose their normal characteristics and acquire epithelial-like features, leading to migration and membrane formation.

• Viral infection hypothesis: Some studies suggest a possible link to herpes simplex virus or other viral infections that may trigger or exacerbate endothelial cell abnormalities.

• Idiopathic origin: In most cases, no specific trigger or genetic cause is identified, and the condition appears sporadically.

Symptoms

Symptoms of ICE syndrome typically develop gradually and may vary depending on the subtype and severity. Common signs and symptoms include:

• Blurred vision: Often due to corneal edema from endothelial dysfunction.

• Eye pain or discomfort: Usually associated with elevated intraocular pressure (IOP).

• Halos around lights: Caused by corneal swelling and irregularities.

• Asymmetrical pupil shape: Due to iris atrophy or abnormal adhesions (synechiae).

• Glaucoma symptoms: Headache, eye pressure, or vision loss from secondary angle-closure glaucoma.

Diagnosis

Diagnosis of ICE syndrome involves a comprehensive eye examination and imaging tests to assess corneal, iris, and angle abnormalities:

• Slit-lamp examination: Reveals corneal edema, "beaten bronze" endothelial appearance, and iris changes.

• Gonioscopy: Evaluates the angle of the anterior chamber and detects peripheral anterior synechiae (PAS).

• Specular microscopy: Used to assess endothelial cell morphology and density.

• Tonometry: Measures intraocular pressure, which may be elevated due to glaucoma.

• Visual field testing and optic nerve imaging: Performed to evaluate the extent of glaucoma damage.

Treatment

There is no cure for ICE syndrome, and treatment focuses on managing its complications, particularly corneal edema and secondary glaucoma:

• Medications:

  • Topical intraocular pressure-lowering agents (e.g., beta-blockers, prostaglandin analogs, carbonic anhydrase inhibitors).

  • Hypertonic saline drops or ointments to reduce corneal swelling.

• Surgical options:

  • Glaucoma surgery: Such as trabeculectomy or glaucoma drainage implants for uncontrolled IOP.

  • Corneal transplantation: In advanced cases with significant corneal decompensation, penetrating keratoplasty or endothelial keratoplasty (DMEK/DSAEK) may be needed.

• Avoiding laser peripheral iridotomy: As ICE-related glaucoma is not due to pupillary block, this procedure is generally not effective.

Prognosis

The prognosis of ICE syndrome varies based on the severity of corneal damage and glaucoma. While the condition is progressive and requires long-term monitoring, many patients maintain functional vision with appropriate treatment. However, vision loss can occur due to irreversible optic nerve damage from glaucoma or significant corneal edema. Regular follow-up with an ophthalmologist is essential for managing intraocular pressure and monitoring corneal health to preserve vision and quality of life.