Objective To evaluate how closely neuropathic-like ocular pain (NOP) symptoms align with a metric of central sensitisation (ie, the presence of persistent ocular pain after topical anaesthetic placement) in individuals with dry eye (DE) symptoms.
Design Cross-sectional study of 224 individuals with DE symptoms seen in the Miami Veterans Affairs eye clinic. An evaluation was performed consisting of questionnaires regarding DE symptoms, NOP descriptors and evoked pain sensitivity testing on the forehead and forearm, followed by a comprehensive ocular surface examination including corneal mechanical sensitivity testing. Subsequent analyses were performed to examine for differences between those with and without ocular pain after topical anaesthetic placement.
Results The mean age was 62 years with 91% being men. DE symptoms and NOP symptoms were higher in subjects with persistent ocular pain after anaesthesia. Most DE signs were not related to persistent pain, with the exception of meibum quality. Individuals with persistent ocular pain also demonstrated greater sensitivity to evoked pain at testing sites on the forehead and forearm. When examining receiver operator characteristic curves considering persistent pain as a gold standard for central sensitisation within the corneal pathway, intensity of ocular pain ratings, Ocular Surface Disease Index scores and sensitivity to light provided the most robust relationships, each with an area under the curve of 0.72.
Conclusions Individuals with DE symptoms and persistent ocular pain after topical proparacaine (a marker of central sensitisation to pain) more frequently report NOP-like symptoms and demonstrate increased sensitivity to evoked pain.
- Ocular surface
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Contributors Conception or design of the work (ERF, RCL, KDS, AG). Acquisition, analysis or interpretation of data for the work (AMC, WF, ERF, RCL, ALM, KDS, AG). Drafting the work or revising it critically for important intellectual content (AMC, WF, ERF, RCL, ALM, KDS, AG). Final approval of the version to be published (AMC, WF, ERF, RCL, ALM, KDS, AG). Agreement to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved (AMC, WF, ERF, RCL, ALM, KDS, AG).
Funding The financial and material support of this paper comes from the Department of Veterans Affairs, Veterans Health Administration, Office of Research and Development, Clinical Sciences Research EPID-006-15S (AG), NIH Center Core Grant P30EY014801, Research to Prevent Blindness Unrestricted Grant, NIH NIDCR RO1 DE022903 (RCL) and the Department of Anesthesiology, Perioperative Medicine, and Pain Management, University of Miami Miller School of Medicine, Miami, Florida, USA.
Competing interests None declared.
Ethics approval Veterans Affairs Medical Center.
Provenance and peer review Not commissioned; externally peer reviewed.