*6.2.4. Sings and symptoms*

The earliest manifestations of ophthalmopathy are usually a sensation of grittiness, eye discomfort, and excess tearing. Other common symptoms are spontaneous retroorbital pain, pain on ocular movement and diplopia. Diplopia is most common in upgaze or in extremes of lateral gaze, because of the involvement of inferior or lateral rectus muscle. About one third of patients have proptosis which can best be detected by visualization of the sclera between the lower border of iris and the lower eyelid when the eyes are kept in primary position.

In severe cases proptosis can cause exposure keratitis and corneal ulcerations. Proptosis is frequently assymetrical. Retraction of the upper eyelid and less commonly of lower eyelid results in lid lag, globe lag, and lagophthalmos. Movements of the lids are jerky, and also there is tremor of lightly closed eyes. These are the non specific manifestations of thyrotoxicosis. Other signs and symptoms are photophobia, swelling of the eyelids, blurring of vision, conjunctival injection and chemosis, periorbital edema.

Decreased visual acuity and color vision, corneal ulceration, and subluxation of globe are present in most severe cases. Blindness may result from corneal ulceration and compression of the optic nerve at the orbital apex due to increased orbital pressure and venous congestion.

Graves' ophthalmopathy can occur in absence of Graves' disease in 10% cases, that's why it is also known as thyroid associated ophthalmopathy, or euthyroid Graves' opthalmopathy. Graves' ophthalmopathy is usually bilateral but it can be unilateral in upto 10% cases.
