Physicians have the option of various adjunctive therapy when prostaglandin analog therapy alone is not sufficiently potent to lower IOP, i.e., they can add one agent, a fixed-combination therapy, or perform selective laser trabeculoplasty (SLT).
“We need to add a second-line agent when the target IOP is not achieved or the target has to be reset when pressure is not lowered enough and progression of glaucoma at the current IOP is noted,” said Sanjay G. Asrani, MD.
But there are a number of considerations surrounding addition of a second-line agent: patient compliance, side effects, allergic reactions, contraindications, and call backs.
Dr. Asrani sets the target IOP range according to the guidelines of the Canadian Society.
Specifically, for patients with advanced glaucoma, the target is in the low teens with the least fluctuation tolerance, i.e., less than 3 mm Hg; for moderate glaucoma, the target range is the mid-teens with acceptable fluctuations of less than 4 mm Hg; and for mild glaucoma, the target range is the high teens with acceptable fluctuations of less than 5 mm Hg, he outlined.
Dr. Asrani, professor of ophthalmology; Head, Glaucoma OCT Reading Center; and director, Duke Eye Center of Cary, Duke University, Durham, NC, enumerated some important considerations.
He noted that roughly a third of patients who are newly treated require adjunctive therapy within one year. When the adjunctive therapy is combined with a prostaglandin, the patients are typically instilling drops twice daily, once in the morning and again in the evening.
When a single drug agent is added, the mean IOP-lowering effect is similar, but the side effects and nocturnal IOP-lowering efficacy differ.