Current Environment:

Frequently asked questions with Dr. David Hunter

Q: What is strabismus and why does it occur in adults?

Hunter Small MDA: Strabismus occurs when eyes don't line up with each other. Usually, one eye seems to be wandering. You may have heard this referred to as "crossed eyes" or "wall eye."

Sometimes it's called "lazy eye" but that is really amblyopia, which we can talk about later. An adult patient might have had this condition since childhood but was never successfully treated, or he or she might have had an illness or injury later in life. People who are born with strabismus will lose binocular vision if they aren't treated, or they will develop double vision.

Q: What is binocular vision?

A: Each of your two eyes sees a slightly different picture of the world. If you have binocular vision, it means your brain can take the two pictures from the two eyes and put them together into a single three-dimensional perception of the world around you. This is a complex skill that is quickly lost when the eyes don't line up. Without binocular vision, your depth perception may be limited. Unlike other vision problems, this cannot be resolved with glasses.

Q: Will strabismus cause double vision?

A: When strabismus begins in childhood, the brain learns to ignore the image from one eye just to avoid double vision. On the other hand, when strabismus begins in adulthood, the brain cannot just ignore one eye. In those cases, double vision can emerge and it can become quite unbearable. Patients might try closing one eye, tilting the head, prisms, "pirate" patches, even covering one eyeglass lens with fingernail polish or tape just to try to get rid of the double image.

Q: You mentioned "amblyopia." What is that?

A: Amblyopia (or "lazy eye") is a problem with vision that develops in childhood. The brain decides to ignore a misaligned eye to avoid double vision. The brain never learns to see clearly out of that eye. Once amblyopia develops in childhood, it has to be treated right away or the vision will never recover. Amblyopia can't be treated in adults, but if the eyes are misaligned they can still be straightened even if amblyopia is present.

Q: Am I too old to have my strabismus treated?

A: As an adult with strabismus, you may have been told in the past that nothing can be done. This is simply not true. In most cases, eye muscle surgery is a successful, safe, and effective treatment for strabismus in adults of all ages. The good news is that it is never too late for surgery. I have personally operated on patients in their 90's, and they were delighted with the results.

In addition to correcting misaligned eyes, treatment can restore binocular vision and even expand the field of vision in some cases. I have many patients who have said after surgery, "Why didn't I take care of this years ago?" They realize how much it affects their self-confidence. Finally, they can look someone in the eye or they can get rid of those heavy prism glasses or patches that they've been struggling with.

Q: I already had an operation, or maybe more than one operation, when I was a child, and the doctor said the muscles couldn't be moved anymore.

A: That does not necessarily mean your condition can't be corrected. Some doctors may not have a lot of education or experience treating complex eye muscle conditions. At Boston Children's Hospital, our doctors treat complex strabismus on a daily basis, using specialized techniques that can benefit patients who might not be able to be treated elsewhere. Of course there are some cases that really can't be fixed, but the only way to know about your case is to visit us for a consultation about your particular eye condition.

Q: But I'm an adult. Why should I go to Boston Children's for treatment?

A: Many adults with strabismus wonder, "Why in the world would I go to Boston Children's Hospital? I'm not a child anymore." The answer is that misaligned eyes are common in children but not so common in adults. Ophthalmologists who care for children tend to have the most expertise in treating eye muscle conditions. At Boston Children's Hospital, ophthalmologists are specially trained to perform the delicate eye muscle surgery required to align the eyes properly, in patients of all ages.

If you do require surgery, it can be performed at one of our adult-friendly surgical facilities or adjacent adult facilities so that you will receive appropriate operative and post-operative care. We do not usually give lollipops or stickers to our adult patients but if you ask nicely...

Q: Is eye muscle surgery to correct strabismus considered cosmetic surgery?

A: Many people believe that their misaligned eyes are a cosmetic issue and that they are being vain for even asking about it. Patients, family members, and friends should understand that there is only one normal position for the eyes and that's to have both eyes looking in the same direction at once. Anything else is a medical disorder that can and should be treated.

You communicate with people in part by looking them in the eye. If you aren't able to look someone in the eye when you talk, that makes it harder to engage attention. Patients have told me how people think they aren't telling the truth because they won't make eye contact. When your communication skills are affected in this way, so is your self-confidence and in many cases, so is your job performance.

You may be less inclined to introduce yourself to a stranger just to avoid having to worry about their reaction to your eye condition. One of my patients teaches Spanish. She came to me concerned that when she would try to look at her students in the eye to address them in Spanish, they wouldn't know that she was looking at them, and so they would not respond to her. She had to spend extra time every semester memorizing all of the kids' names before the first day of class to work around the problem. So it was impeding her work. After successful surgery, the problem went away, and now she can concentrate on all of the other challenges of teaching high school Spanish.

In addition to hindering eye contact, strabismus causes problems with eye function. As I said earlier, some adults develop terrible double vision. Others may have trouble driving because depth perception and side vision are affected. There is no doubt that the treatment of strabismus is considered a reconstructive, not cosmetic, medical intervention.

Q: Do insurance companies cover eye muscle surgery?

A: Most insurance companies do cover eye muscle surgery because it is a medical condition that causes functional disability. Some programs require pre-authorization and some programs may initially decline if they are not educated about the reasons for surgery. In this case we contact the insurance company directly and more often than not, we are able to come to some understanding. Nowadays it is very rare that an insurance company won't pay for this surgery.

Q: What happens during eye muscle surgery?

A: In both children and adults, the surgery is usually performed under anesthesia, although some adults prefer to be awake, and we can do that too. Once the patient is asleep, an incision is made over the white part of the eye, the muscle of interest is separated from the eye and we reattach it with tiny sutures back to the eye but in a different position. (Despite what you may have been told, there is no need to remove the entire eye to perform strabismus surgery.)

When we move the muscle to a new place it means that it either isn't pulling as hard on the eye or it's pulling a little bit harder, whichever is desired to get the eye position straight. This new positioning of the eye muscle changes the angle of the eye. For more details, see Eye muscle surgery, what to expect.

Q: What are adjustable sutures and why are they used?

A: An adjustable suture is a kind of slip-knot that holds the muscle in place. In eye muscle surgery, these sutures allow an ophthalmologist to readjust the position of the eye after surgery, after the patient has had time to wake up from anesthesia. When a patient is asleep during surgery, we can't always tell that the eye has responded to the repositioning of the muscle in the precise way we expect. When the patient wakes from surgery, we might see that the eye isn't exactly where we thought it was.

In the old days we would have to reschedule another surgery months later and start over again. But now, we can just lay the patient down in the recovery room and give anesthetic eye drops. Then, with the patient awake, we can pull those slip-knots one way or another to shift the eye muscle position again to redirect the eye. Believe it or not this doesn't usually hurt, but of course patients are anxious about having sutures adjusted until they've actually been through it and discover that it's not so bad.

Q: How successful is eye muscle surgery?

A: Adjustable sutures allow us to send most patients home with their eye alignment where we want it to be. It's not always perfect though because as the eye heals, the muscle may not stick down the way we thought it would and the eye may drift one way or another.

So we still may have patients come back a couple of months after surgery needing another operation. About 10-20 percent of patients will need more surgery within 3-6 months of the first procedure, depending on how complicated the case is. For the most part, when it doesn't work the first time, we wait a few months, reassess the alignment and then go back and try again. It is very rare that we can't fix it in a subsequent operation.

Q: What are the most serious risks of surgery?

A: Patients typically worry the most about complications from anesthesia, but anesthesiology techniques have advanced a lot over the last 10-15 years. As a result, the anesthesiologists tell me that for a healthy patient, the risks of being injured from anesthesia are equivalent or less than the risk of being injured during a car trip.

In my view it is not a reason to avoid having corrective surgery, any more than you would not drive to the store for milk because of the risk of a car accident. The other very rare complication would be that the eye itself could be injured during surgery, which could cause vision loss. This is also extremely rare, like the chances of being injured during anesthesia.

Q: What are some other complications of surgery?

A: The main complication is that surgery might not correct the problem. Despite our best efforts and careful measurements and adjustable sutures, some patients end up needing more surgery. In some cases, that may mean you develop double vision that you didn't have before, or the double vision that you did have doesn't go away until subsequent surgery.

Sometimes the eyelids may change position enough that something has to be done to correct it. There can occasionally be persistent scarring of the white part of the eye that doesn't go away, but this is pretty rare too except perhaps in patients who have had to have several operations.

Q: Is there pain after surgery?

A: There is going to be some discomfort and blurred vision in the eye for at least a few days, but not so much that you can't function around the home. Your eye may be sore and swollen. Until the sutures dissolve, you might feel that irritation. I tell most adults to take a week out of work.

I ask that they keep water out of the eye and to use some eyedrops for a week, but there are no other limitations. Some patients are back to work in a few days, others may take more than a week if there is double vision or unusual discomfort. The redness can take months to completely resolve, but each day is a little better than the day before.

Q: My doctor told me that there is no point in having surgery, that even if it does help the eyes are just going to drift again years from now.

A: In some cases, the eyes will once again drift apart years after surgery. The surgery doesn't correct the original defect that caused the brain to let the eyes wander in the first place, so the problem might come back years later. But it doesn't always come back. In fact, most patients require just one corrective surgery over a lifetime. If it does come back, it's usually possible for a skilled specialist to again reposition the muscles and restore the benefits of straight eyes for the patient.

Q: I heard that Botox can be used for the eye muscles.

A: In some cases, Botox (botulinum toxin) can restore normal binocular alignment. The advantage of Botox is that it avoids traditional surgery. But its not appropriate for all cases — you'll need to discuss this option with your doctor.

Q: I saw a web page that said that strabismus surgery only works 11% of the time and you will be blinded or killed by surgery. It said that I should do vision therapy instead.

A: The world wide web is open to all who have an opinion. We have treated thousands of patients with eye muscle surgery and most are quite pleased with the results. When we think that exercises might help, we offer that as well. We also use prisms in some cases, or Botox as I have mentioned. It depends on the patient, the patient's disposition, and the details of the condition.

Since we see a large number of patients with strabismus, we often come up with creative treatment ideas that others may not have considered. The only way to know whether surgery is right for you is to have a specialist examine you.

Q: Who do I talk to and how do I schedule a visit?

A: All pediatric ophthalmologists at Boston Children's Hospital evaluate and treat strabismus, but some treat more adults. These doctors are listed at

To schedule an evaluation with one of us, please call the Ophthalmology Department at 617-355-6401. Please be prepared to spend several hours for a complete evaluation of your specific eye condition.