Also medically termed as 'diplopia', double vision is a major concern that should not be taken for granted. This medical disorder of the eyes, causes the affected person to see two or double images of the same object, and this may happen occasionally or all the time. The problem can occur in both the eyes or one. Double vision in one eye is also known as monocular diplopia, and when it is with both eyes, which is more common, it is known as binocular diplopia.
How Does Double Vision Occur
Double vision occurs when the eyes have 'converged' for near objects and are not correctly aligned for viewing distant objects. In this condition, the eyes cease to work as a pair and lose their alignment with each other. What happens ultimately is, the brain remains unable to fuse the two images that have been produced. This happens due to one or more defects in the structure of the eye's optical system. Episodes of temporary double vision can occur from excessive drinking of alcohol or extreme fatigue. Such cases are usually not concerning unless, the problem becomes long-lasting or keeps recurring.
The Responsible Factors
» Astigmatism is one of the causes of monocular diplopia. It is defined as a visual disorder or an optical defect wherein, the vision of the affected person gets blurred. Here, the optics of the eye is unable to form a sharp image of a point object on the retina. Astigmatism occurs due to misshapen cornea or lens and it is a more complex disorder with complex variations, than myopia (short-sightedness) or hypermetropia (long-sightedness).
» Cataract is the most common eye problem which people come up with. It is one of the lens problems that is responsible for causing double vision. A person suffering from a cataract will notice his eye's lens getting cloudy, and may make him feel as if he is looking through a window that is misty or fogged-up.
» Problems in the cornea such as infection or complication caused by LASIK eye surgery could also be some of the common causes of double vision in one eye. Due to such complications, the damaged surface of the eye distorts incoming light and causes double vision.
» Another disorder of the cornea is keratoconus that leads to monocular diplopia. It is an uncommon degenerative eye disorder, wherein, the cornea keeps on becoming thinner. Eventually, it bulges outward and attains the shape of a cone and this ultimately affects the vision.
» Pterygium could also be responsible for causing the problem. It is again a disorder that is related to the cornea, which is believed to be caused by exposure to ultra-violet, dust and low humidity. It is diagnosed by pinkish, triangular-shaped tissue growth on the eye's cornea. The growth, usually, is benign.
» Weak eye muscles may also not allow the affected person to have a single and clear vision of objects. If the muscle of one eye is weak, then it becomes difficult for this eye to move smoothly with the healthy one. This causes gazing in directions controlled by the weak muscle, and eventually leads to problems such as double vision. Some of the common causes of muscle weakness result from myasthenia gravis (an autoimmune illness) and Grave's disease (thyroid condition). Grave's disease weakens the eye muscles and causes image to form on top of the other. This is known as vertical monocular diplopia.
» Diabetes is commonly associated with damaging the nerves responsible for keeping the eye movements coordinated. And this may cause a 'lazy' eye, which in turn, may give rise to diplopia in one or both the eyes.
» Other causes could be:
- Nerve problems such as multiple sclerosis, and Guillain-Barre syndrome
- Brain tumors
- Trauma to the brain
Treatment Measures for the Problem
Treatment is generally done with the help of medicines or surgery, and it is focused on the underlying cause. For instance, if astigmatism is causing it, then the patient would be suggested to wear corrective lenses. Besides this, laser surgery is also an option. And if cataract is the offender, then a surgery is required to get rid of it.
For some people, double vision cannot be reversed or cured completely. For them, treatment options can help in managing the symptoms, and lessening the discomfort to some extent.
Disclaimer: The information provided in this article is solely for educating the reader. It is not intended to be a substitute for the advice of a medical expert.