Self-report questionnaire may aid in screening for depression in patients with low vision

Optom Vis Sci. 2009;86(2):139-145.

A questionnaire based on self-reported symptoms may help clinicians identify patients with warning signs of depression, and the test may be especially useful for patients with low vision because they are at high risk of poor mental health status.

Previous studies have found a higher rate of clinical depression among elderly patients with impaired vision, as much as two to five times greater when compared with similarly aged patients without sight impairments. While a definitive diagnosis of depression should be made by a specialist, the Patient Health Questionnaire was designed for use in the primary care setting to screen for warning signs of depressive disorders.

The Patient Health Questionnaire nine-item depression module, or PHQ-9, has a sensitivity of 88% and a specificity of 88% in diagnosing major depression, and researchers have validated the test in use over the phone and in diagnosing mild, moderate, moderately severe and severe depression.

Using Rasch analysis, researchers validated that a slightly modified version of PHQ-9 - response categories were collapsed to remove potential redundancies - is sufficient for identifying depressive symptoms in the visually impaired population. One hundred three low-vision patients with an average age of 74.7 years completed the survey; 46 of these patients had severe vision impairment.

Although the results of the analysis are based on a small patient population, the authors said that "PHQ-9 has the potential to be used as a tool to measure depressive symptoms in people with visual impairment."