Ocular Myasthenia Gravis

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Synonyms

OMG,

Overview

Ocular Myasthenia Gravis (OMG) is a rare autoimmune disorder affecting 15-20% of Myasthenia Gravis patients, causing fatigue and weakness specifically in the eye muscles. Key symptoms include fluctuating eyelid drooping (ptosis) and double vision (diplopia). Diagnosis involves serological antibody testing (AchR), clinical assessments like the ice test, and electrophysiological tests.

Symptoms

Ocular Myasthenia Gravis (OMG) primarily causes muscle weakness limited to the eyes and eyelids, characterized by fluctuating fatigue. The most common symptoms are ptosis (drooping of one or both eyelids) and diplopia (double vision). These symptoms usually worsen later in the day or after prolonged eye use.

Causes

Ocular Myasthenia Gravis (OMG) is a chronic autoimmune disorder caused by antibodies blocking acetylcholine receptors at the neuromuscular junction, leading to eye muscle weakness. It occurs when the immune system malfunctions, often linked to thymus gland issues, infections, or genetic factors. Symptoms include drooping eyelids (ptosis) and double vision.

Prevention

Ocular Myasthenia Gravis (OMG) cannot be prevented, as its cause is unknown. However, you can manage symptoms and reduce the risk of it progressing to Generalized Myasthenia Gravis (GMG) by using immunosuppressants (like corticosteroids) early, avoiding precipitating factors (infections, stress, certain drugs), and managing risks like thymoma.

Diagnosis

Ocular Myasthenia Gravis (OMG) is diagnosed through a combination of clinical exams (ice pack test, fatigability), specialized antibody blood tests (AchR, MuSK), and, if needed, electrophysiologic studies like single-fiber EMG. It primarily presents with fluctuating ptosis (droopy eyelid) and diplopia (double vision) that often worsens throughout the day.

Prognosis

Ocular Myasthenia Gravis (OMG) generally has a good prognosis, with 50-60% of cases converting to Generalized Myasthenia Gravis (GMG), usually within the first 1–3 years. If symptoms remain ocular for over two years, the likelihood of generalization decreases significantly. Early treatment with immunosuppressants or thymectomy can reduce this progression risk.

Treatment

Ocular Myasthenia Gravis (OMG) is primarily treated with acetylcholinesterase inhibitors (e.g., pyridostigmine) to improve muscle strength, followed by immunosuppressants (e.g., corticosteroids, azathioprine) if needed, particularly to manage ptosis and diplopia. Early treatment with immune modulation may help prevent progression to generalized disease.