Table of Contents
Graves’s ophthalmopathy definition
Graves’s ophthalmopathy – changes in the EYE that occur as a result of Graves’s disease, a form of HYPERTHYROIDISM, and occasionally as a result of other forms of thyroid disease. The most prominent feature of Graves’s ophthalmopathy is EXOPHTHALMOS, an outward bulging or protrusion of the eyes that often is the first indication of Graves’s disease. The exophthalmos results from enlarged extraocular muscles (the muscles that move the eye) and edema (swelling due to retained fluid) in the tissues around the eye and within the ocular orbit (eye socket). This circumstance restricts the ability to move the eyes, particularly upward and side to side, as well as to close the eyelids.
Graves’s ophthalmopathy can involve only one eye (unilateral) though most often involves both eyes (bilateral). Symptoms and consequences range from mild to severe, with about 5 percent of people experiencing substantial loss of vision that may include loss of the eye. Graves’s ophthalmopathy can appear before there are any indications of Graves’s disease, at the onset of hyperthyroid symptoms, or months to years after the diagnosis of Graves’s disease.
Graves’s ophthalmopathy presents a significant threat to vision. The swelling in and around the orbit pressures the structures of the eye and can compress the OPTIC NERVE, which can result in OPTIC NERVE ATROPHY (the death of cells in the optic NERVE) and permanent VISION IMPAIRMENT. The external pressure against the eye also raises the pressure inside the eye (INTRAOCULAR PRESSURE), which can result in GLAUCOMA. The combination of exophthalmos and restricted lid movement prevents the eyelids from closing completely, which allows the CORNEA to become dry. The resulting irritation and INFLAMMATION(KERATITIS) reduces VISUAL ACUITY and also exposes the inner eye to INFECTION. Though the symptoms that threaten vision eventually subside, many of the changes that result, including exophthalmos and vision impairment, are permanent.
Symptoms of Graves’s ophthalmopathy and Diagnostic Path
The symptoms of Graves’s ophthalmopathy include
- exophthalmos (sometimes called poptosis)
- DIPLOPIA (double vision)
- CONJUNCTIVITIS (inflammation of the inner eyelids)
- diminished visual acuity (blurry or distorted vision)
- PHOTOPHOBIA (sensitivity to light)
- excessive tearing
As these symptoms are distinctive for Graves’s ophthalmopathy, the doctor often can make the diagnosis based on their presentation. Tests of thyroid hormone levels in the BLOOD confirm Graves’s disease, if not already diagnosed. Conventional OPHTHALMIC EXAMINATION and SLIT LAMP EXAMINATION allow the ophthalmologist to assess the status of vision and health of the structures of the eye. A COMPUTED TOMOGRAPHY (CT) SCAN helps assess the extent of orbital swelling and compression of the optic nerve.
Graves’s Ophthalmopathy Treatment Options and Outlook
The course of Graves’s ophthalmopathy seems to unfold in two stages, regardless of treatment for or status of the underlying hyperthyroidism. The first stage is the acute or active phase, during which symptoms emerge. During this stage, which extends over 18 to 30 months, ophthalmologic treatment focuses on reducing pressure on the eye and stabilizing vision, and may include
- ophthalmic lubricating drops or ointment to keep the cornea hydrated
- patching the eyes at night to protect the corneas during sleep
- NONSTEROIDAL ANTI-INFLAMMATORY DRUGS (NSAIDS) to reduce inflammation and relieve discomfort
- CORTICOSTEROID MEDICATIONS to suppress the body’s immune response
- ANTIBIOTIC MEDICATIONS to treat bacterial infection of the eyelids (BLEPHARITIS), conjunctiva (conjunctivitis), and cornea (keratitis)
In the second stage of Graves’s ophthalmopathy, the progression of symptoms ends. However, the changes that have occurred are permanent. Fibrous deposits replace lymphocytes in the eye muscles, maintaining their enlargement and continuing the exophthalmos. Treatment in this stage targets minimizing these permanent consequences through surgeries to relieve the pressure within the orbit (orbital decompression), reduce the size of the extraocular muscles (myectomy), and reconstruct the eyelids so they close completely over the eye (BLEPHAROPLASTY). Corneal reshaping (keratoplasty) or CORNEAL TRANSPLANTATION may be necessary to restore vision when damage to the cornea is extensive. If infection resulted in loss of the eye, the ophthalmologist will place a PROSTHETIC EYE.
Risk Factors and Preventive Measures
Graves’s ophthalmopathy occurs only in conjunction with thyroid disorders, nearly always hyperthyroidism. It may appear months to several years before other clinical indications of hyperthyroidism, or a comparable time after beginning treatment for hyperthyroidism. Prompt diagnosis and treatment are essential to preserve vision, as the changes that occur with Graves’s ophthalmopathy are generally permanent. An ophthalmologist should evaluate any changes in the appearance of the eyes. Regular eye examinations help screen for Graves’s ophthalmopathy as well as other eye health problems.