Dexamethasone Injection May Speed IOP Drop in Angle-Closure Glaucoma

By Lorraine L. Janeczko

May 14, 2019

NEW YORK (Reuters Health) - In acute primary angle closure (APAC), subconjunctival dexamethasone injection helps high intraocular pressure (IOP) drop more quickly and improves treatment success rate, researchers in China report.

"The anti-inflammatory treatment of combined subconjunctival injection of dexamethasone for APAC eyes has significant clinical importance," they write in the British Journal of Ophthalmology, online April 18.

Dr. Xiulan Zhang and colleagues at Sun Yat-Sen University Zhongshan Ophthalmic Center in Guangzhou recruited 42 patients with APAC for their randomized controlled trial.

The 21 control-group participants received 1% topical pilocarpine four times daily, topical beta-blocker (timolol 0.5%) two times daily, brinzolamide two times daily, topical alpha-2 agonists two times daily, 250 mg oral acetazolamide three times daily, and 250 mL of intravenous 20% mannitol, once. The 21 injection-group participants received the same drug treatments plus 2.5 mg dexamethasone disodium phosphate by subconjunctival injection 4 mm from the limbus via a 30-gauge needle.

At baseline, and at three, six, 12 and 24 hours after injection, the researchers measured IOP and intraocular inflammation. Examiners and the statistician analyzing the data were masked to group allocation.

While both groups showed significant drops in IOP, 24 hours after treatment, the injection group IOP was significantly lower than that of the control group (18.0 vs. 26.6 mm Hg, P=0.017).

On Kaplan-Meier survival curve analysis, the total success rate of the injection group and the control group were 79.7% and 54.9% (P=0.027), respectively.

When the researchers examined anterior chamber inflammation at 24 hours, they found that the severity of conjunctival erythema, ciliary flush, and pain were significantly lower in the injection group than that in the control group. But both groups had similar findings regarding anterior chamber cells, anterior chamber flare and photophobia.

Dr. Paul Baciu, an ophthalmologist at the Henry Ford Health System in Detroit, Michigan, told Reuters Health by email, "While the study was small, the results do seem to indicate a potential benefit to injecting dexamethasone subconjunctivally for medical management of acute primary angle closure."

"However, optimal treatment of primary angle closure involves laser iridotomy, which was not done in the study," added Dr. Baciu, who was not involved in the study. "Performing laser iridotomy would resolve the pressure elevation much sooner than 24 hours, which was the first time there was a statistically significant difference in pressures between the two study groups. If a clinician has no access to a laser, then perhaps these study results would be applicable in those instances."

Dr. Joel S. Schuman, chair of the department of ophthalmology at NYU Langone Health in New York City, was not surprised by the results.

"That pressure went down faster in the group that received the steroid is not surprising because inflammation is increased in people who have acute primary angle-closure glaucoma," he told Reuters Health by phone.

"The purpose of lowering IOP in patients with acute primary angle-closure glaucoma is only to clear the cornea enough to improve the view of the iris, to prepare the eye for laser surgery," noted Dr. Schumer, who also was not involved in the study. "It may helpful to add a subconjunctival steroid injection to the regimen of medicines used."

The study did not have commercial funding.

Dr. Zhang was not able to respond to requests for comment by press time.

SOURCE: https://bit.ly/2VzcvIw

Br J Ophthalmol 2019.

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