In many instances, visual disturbances, such as floaters, decreased vision, or eye pain are a direct result of eye problems. Less commonly, you can have visual disturbances that occur indirectly, without damage to your eyes. When your eyes seem perfectly fine, the underlying problems are typically the result of a deeper issue.
Stroke is likely the most common underlying problem that can indirectly affect your vision. Sometimes the development of a stroke is preceded by episodes of transient ischemic attacks (TIA), during which there may be similar symptoms of a stroke, but the symptoms resolve spontaneously. One complex visual problem that may occur after a stroke is the loss of vision in specific areas of the visual field. The visual field for each eye can be divided into quadrants. In some instances, people will lose vision in the left (or right) visual field of each eye. Either the inner (right field in the left eye and left field in the right eye) or outer (left field in the left eye and right field in the right eye) portion of the visual field can be lost. Also, a single quadrant of the visual field can be lost in both eyes, such as the upper-right quadrant.
Multiple sclerosis (MS) is an autoimmune disease that causes demyelination of the nerves. Myelin is critical for conducting electrical impulses along the nerve. When these electrical impulses are slowed or otherwise disrupted, any number of problems can occur, such as loss of motor control, slowed gastric motility, and vision disturbances. Vision problems may be one of the first signs of MS, making it difficult to diagnose in the earlier stages since it is erroneously believed to be only a vision problem. In addition to blurry vision, involuntary movements of the eye, pain, and inflammation of the optic nerve can occur. This occurs because the immune system attacks the optic nerve and nerves responsible for eye movement.
Brain tumors can go undetected for years if they are small and do not grow rapidly, or only press against the brain without invading brain tissue. Tumors may cause visual disturbances that are similar to a stroke if they affect parts of the brain associated with visual processing. Another way tumors can cause visual disturbances is if they are located elsewhere in the brain, but cause pressure on the optic nerve. Other concerns with brain tumors that can contribute to vision problems are pressure on blood vessels. This may cause necessary blood vessels to become occluded, resulting in permanent vision loss. As with any tumor, there is the increased risk of increased pressure within the skull, which also cause vision damage or loss.
Although visual disturbances often seem like an eye problem, the complex nature of vision and visual processing means many conditions can contribute to visual problems. When your eyes seem healthy, but vision problems persist, seeing an eye specialist may be necessary to discover deeper issues.
For more information, contact your local ophthalmology office.