Dry eye syndrome can occur in patients with Graves' ophthalmopathy and as a separate disease.  Dry eye syndrome is defined as an abnormal tear film that causes changes to the ocular surface. These changes lead to discomfort and a variety of symptoms including blurred vision, burning, itching, redness, grittiness in the eye and sensitivity to light. Dry eye syndrome can occur in people with autoimmune thyroid disorders, postmenopausal women, the elderly, and in people exposed to eye strain, including excessive computer work or unprotected exposure to sunlight. 

In individuals with Graves' ophthalmopathy, eye dryness is related to exposure due to proptosis and eyelid retraction and aqueous tear deficiency. Mechanical impairment of the lids in GO is caused by the hypertrophy of surrounding orbital muscles, fibrosis of the levator muscle complex, and the increased orbital fat found in orbital connective tissue.  Inflammation in GO contributes to reduced aqueous tear production. In GO, patients also have an abnormal protein composition of their tear fluid, consistent with lacrimal gland dysfunction.

It's important for patients with autoimmune thyroid disease to have annual eye exams so that appropriate treatment can be prescribed if dry eye does occur and to diagnose associated eye problems at an early stage.

Resource:
Selter, J, A Gie, and S Sikder. “The relationship between Graves’ ophthalmopathy and dry eye syndrome.” Clinical ophthalmology, Jan 2015: 57-62.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4287254/pdf/opth-9-057.pdf