Ocular Myasthenia Gravis
Ocular myasthenia gravis is a type of myasthenia gravis that only affects the eyes and eyelid movement. It is characterized by eye muscle weakness that increases during activity and improves after rest. Common symptoms include drooping of one or both eyelids and blurred vision due to weakness of the muscles that control eye movements. Treatment options may include medication, thymectomy, and assistive devices.
What Is Ocular Myasthenia Gravis?
Myasthenia gravis is an autoimmune disease that affects the transmission of signals from nerves to muscles. The name myasthenia gravis comes from Greek and Latin words meaning "grave muscle weakness." However, most cases of myasthenia gravis are not as "grave" as the name implies, and most people with myasthenia gravis can expect to live normal or nearly normal lives.
Ocular myasthenia gravis is a type of myasthenia gravis that only affects the eyes and eyelid movement. The hallmark of ocular myasthenia gravis is eye muscle weakness that increases during activity and improves after rest.
Understanding Nerves and Muscles
Normally when impulses travel down the nerves, the nerve endings release a neurotransmitter substance called acetylcholine. Acetylcholine travels through the neuromuscular junction and binds to acetylcholine receptors, which are activated and generate a muscle contraction.
What Causes Ocular Myasthenia Gravis?
In ocular myasthenia gravis, antibodies block, alter, or destroy the receptors for acetylcholine at the neuromuscular junction. This prevents the muscle contraction from occurring. Ocular myasthenia gravis is considered an autoimmune disease, in which the body's immune system mistakenly turns against itself, attacking its own tissues. Research scientists are still trying to understand why the immune system attacks the acetylcholine receptors.