What Causes Double Vision?
Thyroid Dysfunction
An individual affected by thyroid dysfunction may experience double vision as a result of their condition. The thyroid is a gland in the body responsible for the regulation of numerous processes with the production and administration of hormones. Individuals with a thyroid gland that does not function correctly can experience an associated complication that is called thyroid eye disease. Thyroid eye disease occurs when an individual's immune system abnormally activates receptors in the thyroid gland that result in the excessive production of hormones.
The immune system response that causes thyroid issues is also known to adversely affect the individual's eyes. The immune system attacks the healthy fat and muscle tissues behind the individual's eyes. This abnormal response results in inappropriate inflammation behind the eyes that cause the muscles to become stiff. The eyes become swollen, sore, red, and watery. The muscles cannot move the eyes properly, and double vision occurs because the brain is unable to combine both of the eye's representations correctly.
Myasthenia Gravis
Double vision can be the result of a disease called myasthenia gravis that causes voluntary skeletal muscles to become excessively weak and fatigued with regular use. The muscle weakness myasthenia gravis causes progressively worsens with the normal use of the affected muscle. Any of the muscles in the body can be affected, but the muscles of the throat, face, and eyes are most commonly affected. The reason behind this is these are the voluntary skeletal muscles utilized the most in everyday life.
Weakness in the individual's eye muscles is often the very first symptom of myasthenia gravis to manifest. Muscle weakness is defined as an inability to produce a muscle movement with a maximized effort to do so. When an individual has weakness in the muscles responsible for eye movement due to myasthenia gravis, the eyes are unable to work together with each other and the brain to create a proper depth of field. This discoordination causes the individual to experience double vision.
