Most optometrists know that patient perception of dry eye disease (DED) can be a poor indicator of severity. Some barely realize they have it while others report excruciating discomfort but show few, if any, signs. Now, researchers out of Miami may be able to offer insight on why some patients experience symptoms when others don’t. Chronic pain conditions elsewhere in the body and mental health issues such as post-traumatic stress disorder correlate with more intense symptoms, according to the study published in the May British Journal of Ophthalmology.

The study, conducted by the Veterans Administration hospital in Miami ands Bascom Palmer Eye Institute, looked at 326 patients using quantitative sensory testing to assess nociceptive system integrity and both the Dry Eye Questionnaire-5 and Ocular Surface Disease Index to document dry eye symptoms. It found that mental health indices were positively correlated with a discordance between signs and symptoms of DED. It also found that the “intensity ratings of prolonged after-sensations of pain evoked by noxious hot and cold stimuli were also significantly correlated,” the study says.