Double Vision Made Easy
By Dr Latif Hamed MD
Double vision refers to seeing two images simultaneously. Its causes can be very benign and simple to treat or they can be dangerous, even life threatening and more complex to manage.
If you have double vision, closing either eye and seeing if the double vision goes away or not can be informative. If it does not, then the problem is called monocular diplopia and the causes are usually in the eyeball itself such as dry eye, cataracts, corneal scars, astigmatism or holes in the iris. With monocular diplopia, one of the two images is a ghost image usually touching the clear image. A good eye exam can identify the problem and suggest solutions.
If the double vision goes away when you close one eye, then the problem is called binocular diplopia. This implies that the eyes are misaligned, sort of like a car that needs a front-end alignment. This is where the problem gets hairy as far as causation: the list is encyclopedic and the defect can be in the retina, the eye muscles, the nerves that supply the muscles, the nerve-muscle junction, the brain stem, or the brain. Sifting through the causes and working through the possibilities as well as offering treatments straddle two distinct specialties within ophthalmology, namely neuro-ophthalmology and strabismus surgery, two specialties that I have full fellowship training in and have written books on.
Some causes of binocular diplopia are benign and simple to treat. For instance, the patient may have had a tendency for the eyes to drift since childhood that was kept under control until he or she got older and his ability to "fuse" weakened. Such patients can be treated either with prism in their glasses or with strabismus eye muscle surgery depending on the size of the deviation.
Other causes of binocular diplopia are very serious such as brain tumors and aneurysms. Working up a patient with binocular diplopia resembles very intricate detective work. What clues are there to distinguish between a patient with a benign cause that can be approached leisurely and one with a potential rupture of an intracranial aneurysm where the doctor is racing against time? The challenge here is to identify that subset of patients where the cause is serious and to order the appropriate tests in a timely manner and offer timely referrals and treatments.
Consider the patient who comes in with headaches, double vision with one eye having a dilated pupil and a droopy eyelid. This picture has aneurysm written all over it and prompt action is needed before such aneurysm ruptures. Fortunately, such presentation is not common and the typical patient can be diagnosed and treated more leisurely. But it is important to avoid what I call errors of omission and commission. Errors of omission depict not doing (omitting) something that should have been done, such as performing and ordering appropriate tests to rule out myasthenia gravis in a patient with double vision who is having difficulty swallowing, fatigues easily, and a recent change in his voice.
Errors of commission, on the other hand, indicate doing something that should not be done, for instance performing eye muscle surgery on a patient with double vision secondary to thyroid Graves disease while the eyes and orbit are inflamed and "hot" as this may worsen the situation. Another example would be ordering very expensive complex tests like Magnetic resonance imaging on a patient who has simple but misinterpreted monocular diplopia or broken fusion of an old childhood misalignment. One of my professors at Bascom Palmer Eye Institute in Miami used to say that there are two types of doctors: diagnosing doctors and treating doctors. The thrill of diagnosing a complex diplo-pia problem that stumped others may boast a doctor's ego; and believe me there is no shortage of egos in my profession. How-ever, at the end of the day, what good is a fancy diagnosis if the patients problem was not solved or at least improved? You don't have to possess immense imagination to envision how challenging driving on the highway with double vision can be. Therefore, a diagnosis is only a means to an end, namely tailoring an appropriate treatment plan that results in a happy patient.
One of the most common treatments for double vision is strabismus eye muscle surgery. Each eye has six muscles that attach to it like the reins on the head of a horse and precisely "steer" the eye around. The surgery entails either weakening or strengthening one or more muscle (inserting the muscle in a new location) to change the amount of pull it has on the eye in order to restore proper eye alignment. A great deal of experience 1s required to determine which muscle to operate on and how much weakening or strengthening to do, especially since the surgery is normally performed under anesthesia and whether the diplopia has resolved will be ascertained only when the patient wakes up. One technique to eliminate surprises after surgery is what we call adjustable suture. This is where the operated muscle is not tied permanently to its new position but rather placed on "a bow-tie" and the muscle final position can be adjusted the next day at the office to eliminate any residual diplopia.
Not all causes of diplopia require treatment. Some causes such as microvascular ischemia (mini strokes affecting the nerves that feed the muscles) often resolve on their own in a few months. The challenge is always to identify precisely what one is dealing with. Once you uncover the cause, then the approach to treatment will be very specific rather than just throwing a bunch of treatments on the patient and hoping one will stick.
Worried About Double Vision? We’re Here to Help
If you’re experiencing double vision—whether it comes and goes or appeared suddenly—don’t wait for it to get worse. At Florida Eye Specialist Institute, Dr. Latif Hamed brings decades of expertise in neuro-ophthalmology and strabismus to pinpoint the cause and guide you to the safest, most effective treatment.
Call us today at (352) 237-0090 to schedule a thorough evaluation.
