• Somatosensory Function in Patients With Idiopathic Dry Eye Symptoms

    By Lynda Seminara and edited by Neil M. Bressler, MD

    Journal Highlights

    JAMA Ophthalmology, November 2016

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    Symptoms of dry eye (DE) are com­mon among patients who have chronic overlapping pain conditions (COPCs) and are associated with central sensiti­zation. Patients with DE often charac­terize their ocular pain as burning and report increased sensitivity to wind and light. Galor et al. conducted a prospec­tive cross-sectional study of individu­als with a variety of DE symptoms to investigate whether somatosensory dys­function plays a role in their experience of pain. The researchers found that the severity of neuropathic-like DE pain symptoms correlates with quantitative measures of pain sensitivity at a site remote from the eye (the forearm).

    The quantitative sensory test (QST) was used to measure vibratory and thermal thresholds and cold and hot pain temporal summation (TS) in 118 patients treated at the Miami Veterans Affairs Hospital. In addition to receiv­ing QST on the forearm and an ocular surface exam, participants completed the 5-Item Dry Eye Questionnaire, Ocular Surface Disease Index, and Neuropathic Pain Symptom Inventory modified for the eye (NPSI-E). Psycho­logical status was evaluated using the 9-item Patient Health Questionnaire, the PTSD Checklist–Military Version, and the Symptom Checklist–90 for anxiety.

    Linear regression analyses showed significant associations between overall DE symptom severity and PTSD scores as well as tear breakup time. Anxi­ety and hot pain TS at the forearm accounted for 17% of the variability in ocular burning. PTSD score, tear breakup time, and hot pain TS at the forearm explained 25% of the variabili­ty in sensitivity to wind and 30% of the variability in total NPSI-E scores. Mea­sures of hot pain TS and aftersensations (15 seconds after cessation of stimulus) on the forearm showed the strongest positive correlation with reported DE symptoms, including neuropathic-like qualities of eye pain and pain sensitivi­ty at the cornea.

    In conclusion, these results support the hypothesis that DE symptoms may represent peripheral manifestation of a COPC and may involve somatosenso­ry dysfunction beyond the trigeminal system. (See also invited commentary by Rosenblatt MI.)

    The original article can be found here.