What is Diplopia or Double Vision?
Diplopia also known as Double Vision, is a condition where a person perceives a single object as double. This is a serious symptom and requires medical attention. There are some causes of diplopia which are quite minor, but other serious causes require prompt medical attention.
Causes of Diplopia or Double Vision
A normal human eye can see a single, clear image. Diplopia or Double Vision is a condition where a person perceives two images of a single object. These images can be horizontal, vertical or diagonal. Causes of double vision are many. Trouble with any part of the vision system can cause double vision. Given below are some of the causes:
- Corneal Problems: Corneal problems are a common cause for double vision in one eye only. If the affected eye is covered, this resolves the double vision. Corneal problem comprises of damage to the surface of the eye which distorts the incoming light resulting in double vision. Corneal damage can occur due to corneal infections of the cornea, such as herpes zoster, or shingles etc. These infections can alter the cornea. Another cause for corneal damage is a rare complication of LASIK surgery which causes alteration in one cornea resulting in generation of unequal visual images.
- Problems With The Lens: Cataracts are the most common cause for double vision resulting from lens problems. If both the eyes are affected from cataracts, then both the eyes will perceive distorted images. Cataracts can be removed surgically.
- Problems With Muscle: Weak muscle in one eye causes hindrance in the eye movement and this result in double vision. The causes of muscle problems are many, such as it can occur from Myasthenia gravis which is an autoimmune illness that obstructs the muscle stimulation by nerves. The earliest symptoms are double vision and drooping eyelids. Graves' disease is a thyroid condition and is another cause of weakening of the eye muscles and commonly results in vertical diplopia where a patient sees one image above another.
- Brain Problems: The nerves which control the eyes are linked directly to the brain. Various different causes for double vision have their origin in the brain and these causes are: strokes, aneurysms, increased pressure inside the brain such as occurring from bleeding, trauma or infection, migraine headaches and brain tumors.
- Problems With Nerves:There are various conditions which cause damage to the nerves and in turn lead to double vision and these include:
- Multiple Sclerosis. This condition affects the nerves in the brain or spinal cord and if the nerves controlling the muscles of the eyes are damaged, it results in double vision.
- Guillain-Barré Syndrome. This is a nerve condition which causes progressive weakness and one of the first symptoms may be double vision.
- Diabetes, if left uncontrolled causes nerve damage in one of the eyes which in turn causes weakness in the eye and double vision.
Symptoms of Diplopia or Double Vision
Depending on the cause other associated symptoms with Diplopia or Double Vision are:
- One or both the eyes may be misaligned and the patient may have a wandering eye or a "cross-eyed" appearance.
- Pain upon eye movements in either one or both the eyes.
- Patient experiences pain in the regions surrounding the eyes, e.g. temples, eyebrows.
- Patient may have a headache.
- Patient may experience nausea.
- There may be weakness felt in the eyes or in other areas.
- The eyelids may droop or sag.
Tests to Diagnose Diplopia or Double Vision
If the patient experiences newly developed Diplopia or Double Vision, then it requires immediate medical attention. There are many causes for double vision of which some are serious, so it is important to find out the cause and treat it immediately. Some of the tests used for diagnosing double vision are:
- Medical history and physical exam
- Blood tests
- Computed tomography (CT) scan
- Magnetic Resonance Imaging (MRI).
The best method to arrive at diagnosis is questioning the patient thoroughly and based on the information, an accurate diagnosis can be made. Question which should be asked are:
- When did the double vision start?
- Did the patient fall down and hit his/her head?
- Was the patient unconscious after the fall?
- Was the patient involved in a car accident?
- At what time does the double vision worsens?
- What are the other symptoms which the patient experiences with double vision?
- Does the patient have a tendency to tilt his/her head to one side?
- Does the double vision improve upon tilting the head on either side?
- The patient can be made to focus on something immobile in his/her field of vision, such as a table or a door. Then the patient is asked, if he/she sees the objects next to each other? Or one above the other? In a diagonal manner? Are both the images clear or blurry? Cover one eye of the patient and then uncover it, then cover the other eye and ask the patient if covering the eye is resolving his/her double vision?
Treatment for Diplopia or Double Vision
Treatment for Diplopia or Double Vision comprises of finding out the root cause first and treating it. Double vision can be managed and treated appropriately and by addressing its cause.
- Surgery may be required if the cause is weak eye muscles or an injury resulting in a pinched muscle causing double vision.
- If the cause is myasthenia gravis, then medications for this condition are given.
- Surgery or medicines may resolve Graves' disease, if it is the cause of double vision.
- If diabetes is the cause for double vision, then the appropriate medicines and insulin are given to control the diabetes.
- Sometimes double vision is irreversible, in such cases, treatment comprises of counseling and helping the patient to cope and adjust to living with double vision. The patient can wear an eye patch or special prism glasses so the effect of double vision is minimized.