On the intricacies of treating uveitic glaucoma

Take-Home

Glaucoma is a frequent complication of uveitis arising from the inflammatory disease process itself or from corticosteroid use or both.

By Lynda Charters; Reviewed by Sumru Onal, MD, FEBOphth

Istanbul, Turkey-Management of glaucoma in patients with uveitis should aggressively target intraocular inflammation and the underlying systemic disease.

Sumru Onal, MD, FEBOphth, discussed the numerous medical, laser, and surgical options available to manage these complicated cases.

“Glaucoma develops in from 20% to 40% of patients with uveitis, although historically, the diagnosis has often been made on the basis of IOP elevation alone,” said Dr. Onal, associate professor of Ophthalmology, Department of Ophthalmology, Koc University School of Medicine, Istanbul, Turkey.

“Uveitic glaucoma is more common in some uveitides and numerous mechanisms are involved in its pathogenesis,” Dr. Onal said. “Almost all patients with uveitis with elevations in intraocular pressure (IOP) require treatment with antiinflammatory and antiglaucoma medications. Thirty percent of these patients will require a glaucoma surgery and the percentage increases to almost 60% in pediatric patients.”

A wide range of therapies (i.e., medical, laser, and surgical) are involved in the management of uveitic glaucoma.

Medical therapy

The management of uveitic glaucoma requires treatment of the primary disease and glaucoma. Corticosteroids are still the mainstay of treatment of acute intraocular inflammation, but many patients are at risk of steroid-induced ocular hypertension, she commented. Cycloplegics are used to prevent posterior synechiae. The off-label use of immunomodulatory therapy (IMT) is the standard of care in the uveitis practice today. Apart from controlling the inflammation IMT has a steroid-sparing effect and has the potential to induce long-term remissions. In patients unresponsive to IMT, biological response modifiers are an option. Antiviral drugs are used for anterior uveitis associated with herpes simplex virus and cytomegalovirus.

Medical therapy of elevated intraocular pressure includes the first-line choices of topical beta-blockers and topical carbonic anhydrase inhibitors (CAIs); alpha-2 agonists can be used but avoided in young patients because of adverse effects on the central nervous system; prostaglandin agonists can lower IOP without increasing uveitic flare-ups in patients with controlled uveitis treated with IMT. Oral CAIs can be used with the disease is refractory to topical CAIs. Oral intravenous hyperosmotic agents can be beneficial for patients with acutely elevated IOP.  Patients with uveitic glaucoma often need more than one drug to manage the IOP.

Laser therapy

Laser iridotomy is indicated for patients with pupillary block glaucoma. In cases in which the laser iridotomy closes, a surgical iridectomy may be needed; surgical iridectomy also might be required in pediatric patients with uveitis and pupillary block glaucoma. Argon laser trabeculoplasty generally is not beneficial in eyes with uveitis. Transscleral laser cyclophotocoagulation can be used to treat patients who cannot achieve IOP lowering by any other means. However, the risk of permanent hypotony increases with this treatment.

Surgical management

Glaucoma filtration surgery is indicated in patients with elevated IOP refractory to maximum-tolerated medical therapy. The conjunctiva in these patients should have no or minimal scarring.

“Well-controlled inflammation during surgery decreases the risk of bleb encapsulation and failure,” Dr. Onal said.

Trabeculectomy can be performed with or without the use of antimetabolites to treat uveitic glaucoma. This success rates of achieving an IOP below 21 mm Hg vary (i.e., 50% to 100% at 1 and 2 years postoperatively and from 50% to 76% at 5 years postoperatively). The success rates with unaugmented trabeculectomy have been modest, Dr. Onal noted that the risk of failure in the long term is substantial.

Trabeculectomy with mitomycin C (MMC) is associated with a significant increase in the long-term success of the surgery. A study that compared the short-term (1- and 2-year rates) success of trabeculectomy with MMC in in patients with uveitic glaucoma and those with high-risk primary open-angle glaucoma (POAG) showed no difference between the groups in the short-term when the procedures were the initial surgeries. However, the failure rate at 2 years was higher in eyes with uveitis. Studies of the longer-term success of an initial trabeculectomy with MMC procedure showed no significant difference at 5 years between patients with uveitis and POAG.

The results of trabeculectomy with 5-fluorouracil were found to be comparable to those of trabeculectomy with MMC over the long term. However, both drugs are associated with ocular adverse effects.

Bleb and filter failure are associated with younger age, African-American descent, perioperative/postoperative inflammation, and the need for more surgery among others.

Glaucoma drainage devices are indicated for patients with extreme conjunctival scarring, active/recurrent uveitis, and those who failed trabeculectomy.

“The Ahmed device is advantageous over devices that have no valves because it can prevent hypotony immediately postoperatively,” she said.

In addition, the Ahmed device has high success rates in the intermediate and long term. The Ahmed valve has also been shown to be safe and effective for the treatment of pediatric uveitic glaucoma.

In eyes with uveitis, shunt failure and corneal complications are the most common problems associated with glaucoma drainage devices.

Goniotomy is a minimally invasive procedure that may be consider for pediatric patients before trabeculectomy with its excessive scarring and implant surgery.

Dr. Onal concluded, “Treatment of patients with uveitic glaucoma should first attempt aggressive and comprehensive control of intraocular inflammation and the underlying systemic disease. Uncontrolled IOP can be managed with medical therapy first and then surgical intervention in refractory cases.  Glaucoma drainage devices have increased long-term success rates. Randomized controlled trials should assess the safety and efficacy of new procedures and implants in patients with uveitic glaucoma.”

Sumru Onal, MD, FEBOphth

E: sumruo_md@yahoo.com

Dr. Onal has no financial interest in the subject matter. This article is adapted from Dr. Onal’s presentation during Uveitis at the annual meeting of the American Academy of Ophthalmology.