Some patients may experience symptomatic delayed-onset hyphema after trabeculotomy

The mild adverse reaction is likely triggered by pressure-gradient reversal.

Issue: November 10, 2012

Delayed onset of symptomatic hyphema developed in nearly 5% of patients who underwent ab interno trabeculotomy, according to a study.

“It surprised me how often this delayed bleeding occurs, based on my own clinical experience,” study co-author Arthur J. Sit, MD, told Ocular Surgery News. However, Sit said that the condition is likely underestimated, considering that the cases that were documented were only the patients who had blurred vision and presented to the clinic.

The retrospective case series included 262 patients with a mean age of 74.3 years. Twelve patients (4.6%) experienced delayed hyphema after having undergone electrosurgical ablation of the trabecular meshwork and inner wall of Schlemm’s canal using the Trabectome (Neomedix).

“We remove the blood-aqueous barrier because it is a barrier to flow of fluid,” Sit said. “However, there are conditions where the pressure gradient reverses and you have a higher pressure in the episcleral veins than in the anterior chamber of the eye.”

The study was published in the American Journal of Ophthalmology.

Mechanism of action

The study authors identified an exertion-related increase in episcleral venous pressure as the mechanism of action for the delayed condition.

“We hypothesize that while patients are sleeping, they push on their eye,” Sit said. “When you push on the eye, that temporarily causes an elevation in the intraocular pressure, which slowly drifts back down to baseline. When you then remove the pillow or whatever is pushing on the eye, the pressure in the eye drops suddenly, causing the normal pressure gradient in the eye to reverse and allowing blood to flow from the episcleral veins back into the anterior chamber.”

Other possible causes of hyphema after trabeculotomy are maneuvers that raise pressure in the episcleral veins above the IOP, such as straining, strenuous exercise or a head-down position.

The median time to onset of hyphema was 8.6 months, ranging from 2 months to 31 months.

“All patients have hyphema immediately after surgery, but it usually clears within a few days to a couple of weeks at most. … It was surprising to see hyphema recurring so far out from surgery,” Sit said.

Sit has used the Trabectome since 2006 in 300 to 400 patients.

Mild course

In most cases, hyphema is self-limited.

“We treat most patients as you would treat any bleeding in the eye, with steroid eye drops and limiting activity of the patient,” Sit said. Some patients also had elevated pressure that was sometimes treated with additional glaucoma medications.

In one of the 12 patients, trabeculectomy was performed after a failure to respond to treatment.

“For the other 11 patients, [the hyphema] was a mild adverse event that resolved on its own,” Sit said.

He recommended counseling patients who are susceptible to hyphema to avoid sleeping on the operated side and potentially pressing that eye on a pillow.

“This seems to have helped our patients who are symptomatic,” he said.

For patients unable to change sleeping positions, wearing an eye shield while sleeping may help as well.

Sit recommended discussing late-onset hyphema with all patients for whom the Trabectome is being considered. – by Bob Kronemyer

Reference:

Ahuja Y, Malihi M, Sit AJ. Delayed-onset symptomatic hyphema after ab interno trabeculotomy surgery. Am J Ophthalmol. 2012;154(3):476-480.

For more information:

Arthur J. Sit, MD, can be reached at Department of Ophthalmology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905; 507-284-2787; email: sit.arthur@mayo.edu.
Disclosure: Sit is a consultant to Glaukos.