On conservative clinical grounds alone (eyelid signs not included), Graves' ophthalmopathy (GO) can be identified in 25% of unselected patients with Graves' disease. With detailed orbit imaging (computed tomography, magnetic resonance imaging, or ultrasonography), however, up to 90% of patients with Graves' disease have evidence of ocular involvement.
Rebecca S. Bahn, M.D., of the Division of Endocrinology, Diabetes, Metabolism, and Nutrition at Mayo Clinic, says: "Fortunately, less than 5% of patients with Graves' disease have severe GO.
"The natural history of GO is characterized by progression over 3 to 6 months followed by a plateau phase lasting months to years. Active inflammation underscores both of these phases, and as the inflammation resolves, a third phase of gradual, but incomplete, improvement occurs.
"Overall, 66% of untreated patients with mild-to-moderate GO show spontaneous improvement over a 12-month period, while about 10% of untreated patients have deteriorating GO.
"Several risk factors for GO have become evident. A striking association between cigarette smoking and GO has been noted consistently in clinical studies, and it applies both to active and passive smoking. In addition, smoking has been shown to be associated with progression of eye disease after radioiodine therapy and to adversely influence the course of GO during treatment with corticosteroids and orbital radiotherapy."
Another important factor in prevention of development or progression of GO appears to be early and effective control of thyroid dysfunction. In most cases, the treatment method for hyperthyroidism is of secondary importance to restoring euthyroidism quickly and effectively and maintaining the euthyroid state.
Marius N. Stan, M.D., of the Division of Endocrinology, Diabetes, Metabolism, and Nutrition at Mayo Clinic, advises: "In patients with active inflammation and mild GO, sodium iodide I 131 (131I) therapy with or without corticosteroid use, antithyroid drugs, and thyroidectomy are all acceptable modes of treatment — provided an assessment of the risk-benefit ratio of concurrent corticosteroid therapy is made for those patients choosing radioiodine therapy.
"In cigarette smokers and other patients at increased risk for GO or ophthalmic deterioration, the risk-benefit ratio would likely favor the use of corticosteroids. Besides smoking, other risk factors to be considered include:
"The equivalent of a daily prednisone dose of 0.5 mg/kg beginning the day after radioiodine therapy and tapering over 6 to 12 weeks is generally used for prophylaxis against the development of GO. When GO is severe and remains active, however, it is probably best that 131I therapy be avoided and that antithyroid drugs or thyroidectomy be chosen as the treatment of hyperthyroidism.
"In all patients with GO or at risk for its development, hypothyroidism is to be avoided, and frequent monitoring of thyroid status (eg, every 2 weeks starting at 6 weeks after the therapeutic dose of 131I) is important in the initial phases of treatment, when changes in thyroid status are expected."
Management of GO requires a carefully integrated approach involving endocrinologists and ophthalmologists with expertise in the condition and other experts of particular specialties (eg, otorhinolaryngology, radiation oncology, neurosurgery, dermatology, psychiatry) in consultation, with the goal of preserving the patient's vision and restoring favorable self-perception and quality of life.
Determining the appropriate treatment of patients with GO rests on assessing whether the eye disease is active (inflammatory) or inactive (quiescent) and defining the severity of the ocular symptoms.
James A. Garrity, M.D., of the Department of Ophthalmology at Mayo Clinic, explains: "Most patients with GO have a self-limited and mild disease course and require only local measures for symptomatic relief. These patients have:
"Symptoms resulting from corneal drying are effectively treated with instillation of artificial tear eye drops during the day and use of artificial tear ointment at night, along with taping the eyelids shut if they do not close completely during sleep. Elevating the head of the bed may help improve GO-dependent edema, which can lead to increased soft tissue changes or temporary worsening of diplopia. The use of sunglasses or tinted lenses may assist in decreasing photophobia. In a dusty or windy environment, lateral shields or goggles can be used to avoid corneal irritation. Occasionally, prisms are useful for the correction of mild diplopia."
Patients with active and moderate-to-severe GO may have:
Dr. Bahn advises: "These patients should be assessed by an ophthalmologist to determine whether they require emergent treatment of compressive optic neuropathy or corneal ulceration.
"If no early surgical intervention is needed, the patient may benefit from a course of immunosuppressive therapy. Although oral corticosteroids have been shown to be effective in approximately 66% of patients with active GO, evidence is mounting that intravenous corticosteroids may be somewhat more effective in providing relief from pain, conjunctival edema, and swelling and in rendering the disease inactive. Some medical centers use orbital radiotherapy either alone or in combination with corticosteroids, which may be of benefit to patients with active GO, especially those with extraocular muscle dysfunction.
"Currently, we are recruiting patients with active, moderate-to-severe GO for a randomized clinical trial to determine the effectiveness of rituximab, an immunosuppressive monoclonal antibody targeting B cells, in these patients. Rituximab has been used successfully in the treatment of rheumatoid arthritis and other autoimmune conditions."
Dr. Garrity adds: "Orbital decompression surgery is generally considered for patients with GO who have:
"Patients with active disease who have shown intolerance or insufficient response to immunosuppressive therapy or have debilitating retrobulbar or periorbital pain may also benefit from decompression surgery. Optic neuropathy is our most common indication for orbital decompression. The orbit is decompressed surgically by removing 1 or more of its bony walls, a procedure that expands the eye socket and increases the potential space for orbital contents. In general, thyroid hormone levels should be restored to reference range before any type of orbital surgery is performed, except when severe GO threatens vision and requires urgent orbital decompression."
Dr. Garrity continues: "Typically, eye muscle surgery (strabismus surgery) is performed after decompression surgery if the patient has diplopia postoperatively. In patients not requiring decompression, strabismus surgery may be performed after at least 6 months of stable eye deviation measurements without concurrent corticosteroid therapy. The goal of strabismus surgery is single vision in primary gaze and the reading position; diplopia with deviant gaze may persist after surgery.
"Eyelid surgery for GO usually follows orbital decompression and strabismus procedures, if either or both are needed. Upper-lid retraction is relieved by weakening (recessing) the muscles; lower-lid retraction is treated with analogous procedures, although since it is an antigravity lid, spacers are often required."