To assess the frequency of Dry Eye Syndrome (DES) in patients with Thyroid eye disease (TED).

In a prospective non-comparative observational case series, patients with diagnosis of TED of more than 18 years of age whose severity of TED was Rundle B and Rundle C were recruited. Values for TED clinical activity score (CAS), Ocular surface disease index (OSDI), Tear Meniscus height, Tear film osmolarity, 5-minute Schirmer, Fluorescein tear break up time (TBUT), Fluorescein and Lissamine green stain were recorded. Dry Eye Syndrome (DES) was defined as OSDI score of more than 23 and at least one positive test.

There were 69 patients (138 eyes) with mean age of 39.48 (SD= 14.21) in whom 59.4% (41/69) were females and 89.9% had hyperthyroidism. Rundle B and C of TED were observed in 68.11% (47/69) and 31.88% (22/69), respectively. Mean CAS Score was 1.44 SD:1.13, range: 0-5). Mean palpebral fissure height was 11.68 (SD=2.24, range: 7- 17) and Exophthalmometry was 22.15 (SD= 9.11, range: 13- 24). The mean OSDI score was 27.64(SD=15.72). Normal, mild, moderate and severe OSDI score were observed in 14.5%, 23%, 20.3%, and 33.3% of patients, respectively. The mean tear film osmolality was 294.63 (SD:17.55, range: 260-387). TBUT test showed severe defect in 24.6% and moderate in 31.9 % of patients. Schirmer test revealed mild, moderate, and severe dry eye in 2.9%, 21%, and 24.6% of patients, accordingly. Seventy eyes (50.7%) had underlying meibomian gland disease. Fluorescein Staining and Lissamine Green Staining was positive in 37% and 30% of patients, respectively. Overall DES was found in 41.2% of patients which was significantly different between Rundle B and C (P=0.012) and not significantly different between genders (P=0.3), CAS (P=0.426), PF height (P=0.304 ), exophthalmometry (P=0.719 )

This study found 41.2% DES in patients with TED. It was significantly higher in patients with more severe TED.