Ocular Microbiology and Immunology Group
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2026 OMIG Abstract

Central Pain Mechanisms Predominate in Patients with Ocular Surface Discomfort and Poorly Correlate with Dry Eye Signs

Pedram Hamrah^1,2, Loretta Szczotka-Flynn³, Stephanie Ann McLin Cox², Nancy Gee², Qian Wu⁴,
Abdus Sattar⁴, and Milton Hom⁵

¹Cornea Service, Department of Ophthalmology, Morsani College of Medicine, University of South Florida, Tampa, Florida; ²Department of Ophthalmology, Tufts Medicine, Boston, Massachusetts; ³Department of Ophthalmology & Visual Sciences, Case Western Reserve University, Cleveland, Ohio; ⁴Department of Population and Quantitative Health Sciences, School of Medicine, Case Western Reserve University, Cleveland, Ohio; ⁵Canyon City Eye Care, Azusa, California

Purpose: To determine the contribution of central and peripheral pain mechanisms and their relationship to clinical dry eye disease (DED) signs in patients presenting with ocular surface discomfort, which is commonly associated with infectious keratitis and auto-immune and inflammatory disorders.

Methods: Cross-sectional analysis of 477 subjects across 16 sites with ocular surface discomfort undergoing visual analog scale (VAS) assessment before and after topical anesthetic and hypertonic challenge. DED signs included tear break-up time (TBUT), Schirmer test, and corneal staining.

Results: Following anesthetic, 50.3% of eyes showed no improvement or worsening pain, while 18.1% demonstrated complete pain relief; the remaining eyes exhibited partial improvement, indicating mixed pain. Hypertonic challenge induced >2-step VAS increase in a 44.3%, of which 82.8% had abnormal TBUT (<7), 40.2% Schirmer <10 mm, and 14.9% staining >4; 88.9% exhibited >1 abnormal sign but only 7.3% met all three.

Conclusions: Ocular surface discomfort is predominantly driven by central and mixed pain mechanisms and shows marked discordance with traditional DED signs, highlighting limitations of conventional topical therapies.