Background: Good adherence to ocular hypotensive agents is important to control intraocular pressure and hence to prevent progressive glaucomatous optic nerve head damage. Periodic investigation of adherence is crucial in glaucoma treatment. The purpose of this study was to assess level of adherence to ocular hypotensive agents and to identify factors affecting adherence among glaucoma patients at a tertiary public eye care center.

Methods: The study was a hospital-based cross-sectional study that was conducted in Menelik II Referral Hospital from June 1, 2015 to July 31, 2015. A systematic random sampling technique was used to select 359 study participants from the source population. The study patients were interviewed and their medical charts were reviewed using a pretested structured questionnaire. Adherence was assessed using Morisky Medication Adherence Scale - 8 and adherence determinant factors were identified using multivariate binary logistic regression analysis. The association was declared statistically significant at p < 0.05.

Results: Among the 359 study glaucoma patients, 42.6 % were adherent to their prescribed hypotensive agents. Higher educational level (AOR = 4.60, 95 % CI: 1.01-21.03, p < 0.049), being self - employed (AOR = 6.14, 95 % CI: 1.37-27.50, p < 0.018) and taking lesser frequency of drops (AOR = 2.89, 95 % CI: 1.25-6.66, p < 0.013) were significantly associated with adherence, whereas being a farmer (AOR = 0.07, 95 % CI: 0.01-0.75, p < 0.028), having very low monthly family income (AOR = 0.22, 95 % CI: 0.06-0.77, p < 0.019) and self - purchasing of medications (AOR = 0.30, 95 % CI: 0.10-0.93, p < 0.036) were significantly associated with non-adherence.

Conclusions: The study has identified the adherence level to the prescribed ocular hypotensive agents to be sub-optimal and is influenced by different factors among glaucoma patients of the public tertiary center. We recommend glaucoma care providers to pay due attention on the importance of adherence.