Thyroid-associated eye disease (TED), is a cosmetically disfiguring and functionally incapacitating, chronic, infiltrative ocular disease that is usually associated with Hyperthyroidism [1]. However, it may be seen with other thyroid diseases such as Hashimoto’s thyroiditis and thyroid cancer [2]. More than 50% of patients with Hyperthyroidism will develop mild to severe, unilateral or bilateral TED at some point during their disease with severe forms affecting 3% to 5% of patients. Onset of eye disease is usually concomitant with the onset of hyperthyroidism, but ophthalmopathy may precede or follow hyperthyroidism and even occur in thyroid or hypothyroid patients. [2].

TED is seen six times more frequently in females than males (86% versus 14% of cases, respectively), but the female: male ratio is reduced to 4:1 with severe forms of eye disease [3,4,5,6]. Palikhe et al. from Nepal reported 71.7% prevalence of TED; 75% were hyperthyroiditic, 16.7% hypothyroiditic, and 8.3% euthyroid [7]. Kashkouli et al. showed that 53.4% had graves, 44.1% hypothyroid, and 5.5% euthyroid [8]. Dry eye syndrome (DES) is defined by an abnormal tear film that results in changes to the ocular surface, which can lead to ocular discomfort. Its symptoms may include blurred vision, burning, itchiness, redness, or grittiness in the eye, and sensitivity to light.

DES is a common disease and is increasingly prevalent among people with autoimmune disease and thyroid disorders, in postmenopausal women, and in the elderly. Two main types of dry eye are known, which are, namely, aqueous tear-deficient dry eye and evaporative dry eye. Aqueous tear-deficient dry eye is caused due to lack of lacrimal secretion and the conjunctiva failing to secrete water, while evaporative dry eye is caused due to certain internal and external causes that serve to accelerate the evaporation of tears. Disorders in the meibomian gland are the most common internal cause of evaporative dry eye.

Moreover, ocular surface disorders and the wearing of contact lenses are the most common external causes for evaporative dry eye [9]. Instability in the tear film can lead to dryness since tear film stability depends on several factors, such as tear osmolarity, tear clearance, appropriate blinking, normal lacrimal function, and the maintenance of a normal ocular surface.

Intraocular pressure (IOP) was measured in primary position and upward gaze. Retraction of either upper or lower eyelid was defined as any exposed superior or inferior sclera beyond the limbus in the primary gaze. Dry eye was also diagnosed clinically.

Statistical analysis: The recorded observations were analyzed using the SPSS Version 18. (SPSS 18‑ IBM Corp. Armonk, NY). Categorical variables were expressed as counts and percentages. The Chi‑square test for independent proportions or Fisher’s exact test was used. P<0.05 is considered statistically significant.

Written Informed consent was taken after thoroughly explaining the objectives to the participants. The study was approved by Institutional Ethics Committee.

Table-1: Demographic Details and Clinical Characteristics of Study Participants (N=70)

*p<0.05 is statistically significant

According to Table 1 a total 70 patients with established hyperthyroidism were studied. The study was female preponderance comprising 25% of hyperthyroid patients. The mean age in males is 42.5 ±22.4 years and in females is 44.6±16.6 years which was found to be statistically significant (p<0.05). Increased Intraocular pressure was seen in of hyperthyroid patients and the association was found to be statistically significant.

Table-2: Distribution of presenting eye signs in Hyperthyroid Patients (N=70)

*p<0.05 is statistically significant

As per Table 2 the most common presenting eye sign was found to be diminished vision in almost all patients of Hyperthyroidism which was found to be statistically significant. (p<0.05).

In a study by Haefliger et al., performed on 500 patient charts, the prevalence of increased IOP was noted to be 24% [13]. In 2007, Behrouzi et al. reported a prevalence of 11%, and He reported an incidence of 31.3% in Chinese patients [14]. With persistence of exophthalmos, there was an increased chance of development and progression of glaucoma signs such as cupping of the disc and visual field defects. The present study had (36.6%) cases of increased IOP in primary position. Increase in IOP can be explained by increased pressure on the globe by enlarging muscle masses and by impediment of episcleral outflow. Increased IOP was seen more in men (36.6%) than women (10%), P=0.01. Persistence of hyperthyroidism may lead to progressive increase of IOP, leading to overt manifestations of glaucoma such as cupping of the disc and visual field loss, therefore, follow-up of patients in this regard is warranted.

The studies by Besharati, Perros and Lee also demonstrated the same trend. [5,10,12] It appears that even though dry eyes and raised intraocular pressure was more frequently seen in females, a more aggressive form is seen with increasing age and the male gender. The ocular complaint was observed in 44.27% of patients; foreign body sensation being the most common presenting symptoms in 61.79%. In a study done by Kashkouli et al., bilateral proptosis (9.9%), burning sensation (5.4%), pain behind the eye (5.3%), and puffiness (4.7%) were the most common signs and symptoms [13]. The frequency of in the present study is 67% of have common symptoms.

Dry eye has historically been explained by increased tear evaporation from proptotic eyes. [15,16] Nonetheless recently it has been shown that the lacrimal gland may also be a target of TSH antibodies [17]. Clinical evidence of dry eye was noted in 12 (17%) of our patients significant in women when compared to male. When dry eye was cross-referenced with presence of proptosis, it was not found to be significant, indicating that lacrimal gland dysfunction should be considered as an entity by itself and not merely a consequence of proptosis. Interestingly, it has been shown by Gupta et al. that in patients presenting with dry eyes, previously undiagnosed thyroid dysfunction may be the underlying cause [18].

Limitations: Smoking has been shown to correlate with the severity of hyperthyroidism but in the present study there were only 10 smoker who had hyperthyroidism, yet there was not enough data to make a