Tinnitus was significantly associated with pre-existing primary open-angle glaucoma, researchers reported in the Journal of Glaucoma.

“The underlying mechanism relating glaucoma and tinnitus is not exactly clear,” Tung-Mei Kuang, MD, PhD, of the department of ophthalmology at Taipei Veterans General Hospital in Taiwan, and colleagues wrote. “Vascular dysregulation is one possible common pathway. Although POAG [primary open-angle glaucoma] is multifactorial, and a clear pathophysiology is not established, it has been suggested that the glaucomatous ganglion cell damage is caused, at least in part, by chronic impairment of blood supply to the optic nerve head.”

Seeking to better understand the association between POAG and tinnitus, Kuang and colleagues conducted a population-based, case-control study using data from the Taiwan National Health Insurance Research Database. Participants were predominantly of Han-Chinese ethnicity and included 542,682 with tinnitus (mean age, 55 years; 43% men) and 1,628,046 controls.

Of 2,170,728 total participants, 85,257 had POAG before the index date of tinnitus, 25,506 were patients with tinnitus, and 56,761 were controls (P < .001). Overall, researchers determined that about 30% of patients with tinnitus were more likely to have pre-existing POAG than controls.

The study also showed tinnitus was significantly associated with hearing loss (P < .001), hyperlipidemia (< .001), rheumatoid arthritis (P = .005) and idiopathic intracranial hypertension (< .001).

“[Eye care providers] should be aware of this association, and further studies are needed to understand the underlying mechanisms,” the authors concluded.

Article originally appeared on Healio