Double Vision - Diplopia 

Double vision, termed diplopia, causes a person to actually see two images of a single object or item. It can occur in both eyes (Binocular Diplopia) or it may occur in just one eye (Minocular Diplopia). Double images may appear beside, on top of, or diagonally to each other. There are a variety of treatment methods for double vision depending on the type, cause, and extent of the condition.

Your eyes and brain work together in an amazing synchronized fashion to create 3D images of your environment. Your eyeballs are round and almost an inch in diameter. They are located in the orbits (eye sockets) at the front of your skull. Six ocular muscles suspend and move each eye.

 

Light rays enter the front of your eye and are interpreted by your brain as images. Light rays first enter your eye through the cornea, the “window” of your eye. The cornea is a clear dome that helps your eyes focus.

 

The anterior chamber is located behind the cornea and in front of the iris. The anterior chamber is filled with a fluid that maintains eye pressure, nourishes the eye, and keeps it healthy. The iris is the colored part of your eye. Eye color varies from person to person and includes shades of blue, green, brown, and hazel. The iris contains two sets of muscles. The muscles work to make the pupil of your eye larger or smaller. The pupil is the black circle in the center of your iris. It changes size to allow more or less light to enter your eye.

 

After light comes through the pupil, it enters the lens. The lens is a clear curved disc. Muscles adjust the curve in the lens to focus clear images on the retina. The retina is located at the back of your eye.

 

Your inner eye or the space between the posterior chamber behind the lens and the retina is the vitreous body. It is filled with a clear gel substance that gives the eye its shape. Light rays pass through the gel on their way from the lens to the retina.

 

The retina is a thin tissue layer that contains millions of nerve cells. Think of your retina as a movie screen that receives images of what you see. The nerve cells are sensitive to light. Cones and rods are specialized receptor cells. Cones are specialized for color vision and detailed vision, such as for reading or identifying distant objects. Cones work best with bright light. The greatest concentration of cones is found in the macula and fovea at the center of the retina. The macula is the center of visual attention. The fovea is the site of visual acuity or best visual sharpness. Rods are are located throughout the rest of the retina.

 

Your eyes contain more rods than cones. Rods work best in low light. Rods perceive blacks, whites, and grays, but not colors. They detect general shapes. Rods are used for night vision and peripheral vision. High concentrations of rods at the outer portions of your retina act as motion detectors in your peripheral or side vision. 

 

The receptor cells in the retina send nerve messages about what you see to the optic nerve. The optic nerves extend from the back of each eye and join together in the brain at the optic chiasm. The optic chiasm is the place where the optic nerves from the right and left eye meet and cross one another. From the optic chiasm, the nerve signals travel along two optic tracts in the brain to the occipital cortex.  

 

The lateral geniculate bodies are the relay station for nerve signals between the eyes and brain. From the lateral geniculate bodies, the nerve signals travel to the occipital cortex in the brain. The occipital cortex is the brain structure that processes information received by the eyes into what you perceive as vision.

Double vision may occur for a variety of reasons. The most common cause of double vision is from functional problems in the visual system. Functional problems refer to the misalignment of the two eyes or problems with how the eyes work together. Double vision caused by functional problems is termed binocular diplopia.

 

Structural defects in the eye are a less common cause of double vision. Examples of structural defects include cataracts or lens irregularities. Structural defects can cause double vision in just one eye. Double vision caused by structural defects is called monocular diplopia.

 

Temporary diplopia can result from head injuries. You should contact your doctor immediately if you received a blow to the head and experience double vision. Temporary double vision may also result as the side effect of some medications or being drunk.

The only symptom of Diplopia is seeing two of a single object. Depending on the cause, double vision may be constant or occur every now and then. Temporary double vision goes away with time. Double vision may be present when you look at things close-up or far away, or both. It may occur in just one eye, each eye, or when you use both of your eyes together. The doubling does not usually go away when you look in different directions.

Your doctor will review your medical history and complete a thorough eye examination to determine the cause of your double vision. It is necessary to determine the cause to recommend the best and most appropriate treatment for you. You should tell your doctor about your symptoms, including the position of the double images and anything that makes your symptoms worse or better. You should let your doctor know if the double vision is intermittent and if it occurs at different times of the day.

 

Your doctor will check how well your eyes move together and how well your eye muscles work. The functioning of your facial nerves may be evaluated with simple clinical tests. Your doctor will check your vision. In some cases, lab tests or medical imaging tests may be ordered to rule out possible underlying medical conditions that might contribute to double vision.

The treatment of double vision depends on the type, cause, and extent of the condition. There are a wide variety of treatments for double vision. In some neurological cases, the condition is simply monitored carefully by the doctor until it resolves by itself. Eye patching may be used to help resolve the condition. Newer patching concepts are hardly noticeable and include glasses with stick-on opaque areas. Some types of double vision may be corrected with prism glasses or special contact lenses. Exercises may be used to strengthen the eye muscles, retrain the nerves, and improve functioning. Surgery may be used to treat the muscles that move the eye. Your doctor will discuss your condition with you and help you decide the treatment option that is best for you.