Ocular Surface Changes in Patients with Thyroid Eye Disease: An Observational Clinical Study

BACKGROUND: This study aimed to compare ocular surface parameter changes in active and inactive thyroid eye disease (TED) patients and controls. METHODS: This is an observational clinical study that included 60 eyes divided into three groups following clinical activity score (CAS) assessment. The first group (Group A) comprised 20 eyes with active TED (CAS score ≥3/7), while the second group (Group B) comprised 20 eyes with inactive TED (CAS score <3/7) and the third group (Group C) comprised 20 eyes of controls without dry eye manifestations. The palpebral fissure height, degree of proptosis, degree of lagophthalmos, ocular surface disease index (OSDI), Schirmer test without anesthesia, corneal fluorescein staining (CFS), non-invasive tear break-up time (NITBUT), tear meniscus height (TMH), lipid layer thickness (LLT), meiboscore, meibomian gland dysfunction (MGD), and thyroid antibodies were assessed and data were compared between study participants. RESULTS: The mean OSDI was 40.0 ±5.80 in Group A, which significantly differed from Group B with a mean of 26.5 ±5.10 (p=0.02). There were significant differences between the two groups regarding palpebral fissure height (p=0.02), amount of proptosis (p=0.008), and degree of lagophthalmos (p=0.001). Similarly, active TED patients had more decreased tear secretion than inactive TED patients (p=0.012). Moreover, active TED patients showed a significant increase in Meibomian gland loss areas in both upper and lower eyelids compared with inactive TED patients (p=0.001). Corneal fluorescein staining also revealed a statistically significant difference between the studied groups (p=0.0001). CONCLUSION: This study showed differences regarding ocular surface parameter changes between both active and inactive TED and compared to controls. Further studies are needed to confirm these results.