In a large, retrospective, case-control study involving over four million patients, Zhang et al[2] found that 22% of patients with glaucoma had depression compared with 2.3% of patients without glaucoma. Berchuk et al[19] followed over 3000 glaucoma suspects over an average of more than 3 years and found that patients with concomitant anxiety and depression had a significantly higher risk of later developing glaucoma. However, it is well-established that many glaucoma patients fail to fill their prescriptions or discontinue eye drop therapy.[24] Patients with low adherence to glaucoma medications are also more likely to have worse visual field defect severity.[25] In addition, patients with severe glaucoma are less likely to be compliant with recommended follow-up times than those with mild or moderate glaucoma.[26] Depression has therefore been thought to contribute to glaucoma progression. Prevalence of Depression in Glaucoma Patients A number of studies have found an increased prevalence of depression in glaucoma patients. [Extracted from the article]