Presurgery Corticosteroids May Worsen Conjunctival Hyperemia Post Trabeculectomy

Patients who took steroid eye drops before trabeculectomy for glaucoma had worse conjunctival hyperemia and a shorter noninvasive tear breakup time following the surgery, according to a new report.

This study, published in the Arquivos Brasileiros de Oftalmologia, is based on clinical and keratograph analyses of 31 patients with glaucoma, the incidence of which is rising on a global scale, the investigators noted.

As part of their glaucoma treatment, many patients take eye drops to relieve ocular pressure. These drops, however—in particular, benzalkonium chloride, the preservative they contain—have been associated with an increased risk of ocular surface disease (OSD). The risk of OSD multiplies when patients take more than 1 type of eye drop, the study authors noted, and previous study findings show that the inflammation associated with such medications can lead to trabeculectomy failure.

Recent studies results suggest, however, that corticosteroids can reduce irritation in OSD. Given this potential to reduce OSD, which itself can be an adverse effect of trabeculectomy, the present study investigators sought to see how the use of preoperative steroid eye drops might affect patients scheduled for filtration surgery.

They recruited 31 patients (31 eyes) with glaucoma. The mean (SD) patient age was 69.9 (10.77) years, their mean visual acuity was 0.40 (0.34) logMAR, and they all had been using at least 3 topical eye drops for longer than 6 months before the study.

For the study, the patients were given loteprednol etabonate ophthalmic suspension 0.5% for 4 times per day in the week before their surgeries, and they were assessed by an ophthalmologist and keratograph before their surgeries and 2 weeks after surgery.

Two weeks after surgery, clinical assessment of the patients showed no significant differences in bulbar redness, tear breakup time, or keratitis compared with their initial assessments. However, a keratograph analysis did show significantly different bulbar redness and average noninvasive tear breakup time, the authors said.

“Patients presented more conjunctival hyperemia and shorter noninvasive tear breakup time after trabeculectomy as compared with before surgery (P = .013 and P = .041, respectively),” they said.

The authors noted that earlier studies have suggested that loteprednol etabonate led to improvement in OSD and that their conflicting finding may be due to the fact that the topical drops were given after surgery in those earlier studies.

“[B]ecause these patients had recently undergone trabeculectomy surgery, they might present with worse OSD,” they wrote. “To our knowledge, this preliminary study is the first to attempt to compare the same patient before and after trabeculectomy using keratograph analysis.”

The authors noted a number of limitations to their study, such as its cross-sectional design and small sample size. In addition, although the patients were evaluated by a single ophthalmologist, the subjectivity of the findings could have affected the results.

Still, they said, the use of objective measures in addition to the subjective assessment strengthens their results. They concluded that despite loteprednol etabonate’s association with OSD improvement, its effect when given prior to trabeculectomy appears to increase conjunctival hyperemia.

Reference

Fares NT, Portela RC, Machado LF, et al. Effect of steroid eyedrops after trabeculectomy in glaucoma patients: a keratograph analysis. Arq Bras Oftalmol. 2021;84(4):345-351. doi:10.5935/0004-2749.20210050