Researchers recently crunched the numbers and discovered glaucoma care—whether pharmaceutical, laser or incisional—is not affordable for most patients, in both developed and developing countries.

After studying data from 38 nations, 21 of which were developing countries, and comparing glaucoma intervention costs with the median annual household income, the team designated a price tag of 2.5% of income or below to be an affordable intervention. While considerable variability existed from country to country—trabeculectomy was anywhere from 0.3% to 42%, for example—timolol came out on top as the most affordable, registering above the affordable line in only two countries. However, latanoprost was deemed affordable in all developed countries and even six developing ones.

Trabeculectomy was the most expensive for most countries, above the affordability threshold in 95% of developing countries and just shy of 60% in developed countries as well.

Laser trabeculoplasty sat somewhere in the middle, and was deemed unaffordable in 65% of developing countries and 24% of developed countries. Still, this intervention was more affordable than a three-year supply of latanoprost in 53% of countries included in the study.

“Successfully reducing global blindness from glaucoma requires addressing multiple contributing factors, including making glaucoma interventions more affordable,” the study authors conclude.