Eye pain and ocular surface characteristics in Postural Orthostatic Tachycardia Syndrome (POTS): The role of autonomic dysfunction

Postural Orthostatic Tachycardia Syndrome (POTS), an autonomic nervous system dysfunction, is frequently associated with ocular symptoms including pain and dryness. This study aimed to characterize ocular surface findings in POTS patients to clarify whether these symptoms reflect classic dry eye disease or altered sensory processing related to autonomic dysfunction. A retrospective observational study was conducted on patients with confirmed POTS who underwent standardized ocular surface evaluations at a tertiary academic center between 2019 and 2024. Demographics and medical history were extracted from records. Assessments included pain ratings (0-10 Likert scale), proparacaine response, Schirmer testing, ocular staining score (OSS), and in vivo confocal microscopy (IVCM) when available. Forty-three patients (39 females; mean age 45.1 ± 14.0 years) were included. Thirty-eight reported ocular pain and dryness. Among 21 patients with recorded pain scores, the median (IQR) was 5 (4), reduced to 4 (4.5) after proparacaine. Median Schirmer score was 5 mm (IQR 27), with 13 patients ≤5 mm. Median OSS was 0 (IQR 2), with only 4 patients showing OSS>1 with improved symptoms after proparacaine, suggesting neuropathic etiology in 34 patients. IVCM, available in six cases, revealed reduced nerve density and microneuromas. Migraine was the most common comorbidity (76.7 %) and was strongly associated with pain without staining (OR = 15.0; 95 % CI 2.65-85.0; p = 0.002). POTS patients frequently report ocular pain and dryness, yet objective signs of dry eye are uncommon. These findings underscore the need for ocular surface staining to distinguish dry eye disease from neuropathic ocular pain, suggesting that altered corneal nerve function in autonomic dysfunction may drive symptoms.