Today's post focuses on a type of esotropia called accommodative esotropia. Don't know what the word esotropia means? Let's start with some basics then. Please read my "Breaking Down Strabismus" post first to get the background information you need before continuing onward!
Accommodative esotropia is a form of strabismus where the eyes turn inward because the eyes are working really hard to focus on objects up close. This is typically seen in children who are farsighted (medical term for farsightedness: hyperopia). A child with a moderate or high amount of farsightedness will need to work hard to overcome their farsightedness and focus on an object at near. The eyes have a natural tendency to cross in as they try to focus on an object up close. This crossing in of the eyes is part of the brain's accommodation-convergence reflex. How this reflex is coordinated between the brain and eyes is far more complex then what I am describing here. For the purposes of this post, just know that the eyes have a tendency to cross inward to focus on an object that is near.
Usually, a child with accommodative esotropia will start to have crossing in of the eyes anywhere between 6 months to 7 years of age. The crossing in of the eyes may start off as intermittent, but can become constant over time. This type of esotropia tends to run in families. Sometimes it can be associated with unequal vision between the eyes if one eye has a higher prescription than the other of if one eye crosses in more than the other (medical term: amblyopia) . If the crossing starts at an older age (around 7 years old for example), it may even cause double vision.
How do you treat it?
The majority of eye doctors will start off by correcting the farsightedness with glasses to help relax the eyes' reflex to cross in. I can't emphasize enough that a child needs to wear his/her glasses full time before you start to see an effect from the glasses. If there is unequal vision between the eyes (medical term: amblyopia), the child may also need to do patching or use atropine eye drops to get the vision between the eyes to be more equal. Sometimes the eyes cross in more up close then when looking at an object in the distance. In these situations, an eye doctor may recommend adding a bifocal to the glasses to see if the stronger prescription at near helps better correct the eye misalignment at near.
What if the glasses do not seem to be helping with the crossing?
The first question I would ask in response to this is whether your child has been wearing his/her glasses full time. It can be really frustrating to keep glasses on an infant or toddler. Often, children this age just do not like having anything on their faces, but glasses really are the most effective way to correct for this type of esotropia. First of all, the glasses are helping the child see better by correcting his/her farsightedness and preventing development of a lazy eye (medical term: amblyopia). Secondly, the glasses are also helping reduce the tendency for the eyes to cross in. The only way the glasses can work is if the child is wearing them consistently. So, my first response to this question would be to see if your child is wearing his/her glasses full time before we say that the glasses are not working.
Any tips to keep glasses on my child?
This question does deserve its own post and I will have to write one up soon! I would say there are several ways to approach this.
The eye doctor can double check to make sure that the glasses were properly made and that the correct prescription is in the glasses. The eye doctor can also recheck that the glasses prescription recommended is correct by doing a repeat eye exam.
I have found that a major issue with getting a child to wear glasses is fit. If the eyeglasses are too big or too small, they can be uncomfortable on the face. Double check that the nose piece of the glasses and the ear pieces sit properly on those areas of the face. Double check that the glasses are not too close to the eyes and pressing on the forehead, causing your child's eyelashes to turn in, or causing constant fogging of the lenses. If the material for the frame seems heavy, you can consider changing out the frame style and material. Adding on a strap also seems to increase the likelihood that glasses stay on a child's head.
Let's say that you have double checked the glasses fit and the prescription and there is nothing wrong with the glasses themselves. This is where it gets tricky. Now a lot of the recommendations are behavioral. You can try to encourage glasses wear by having other family members wear their glasses around your child. You can try to encourage glasses wear if a favorite doll or stuffed animal also wears glasses along with your child. Over the years I have seen families develop creative games and rewards for each day or period of time their child wears glasses. Depending on the age of the child, some families have tried socks or mittens on their infants' hands to make it harder for the child to take the glasses off. No matter the approach, I recommend sticking with it. The majority of children eventually get used to wearing the glasses.
If all else fails, there are certain situations when the eye doctor can prescribe an eye drop to be placed in both eyes for a few days to help with the acceptance of glasses.
Wearing glasses can be fun when your favorite toy is also wearing glasses!
My child has been wearing glasses consistently and the eyes are still crossing in. Now what do we do?
There are cases where glasses only help correct some of the eye crossing. If your child has worn glasses consistently for a good couple weeks to months and the eye crossing has not gone away completely, your eye doctor may say that your child has something called partially accommodative esotropia. This means that the glasses help correct some or most of the eye crossing, but not all of it. If the majority of the eye crossing has been fixed with glasses and the child seems to have good depth perception and equal vision, then that little bit of crossing may be okay to observe carefully. If the eye misalignment is still really large despite full time glasses wear or the child does not have good depth perception or continues to have unequal vision despite glasses +/- patching and eyedrops, the next step may be strabismus surgery to help correct the remaining crossing. Now, I do want to clarify that strabismus surgery can help correct the misalignment, but it does not get rid of the need for glasses wear. Usually a child still will need the glasses after strabismus surgery to help with the farsightedness.
Will my child always need to wear glasses if s/he has accommodative esotropia?
Our eyes tend to increase in farsightedness up until about 7-8 years of age. By around age 8, the eyes then begin to grow longer and then reverse and become increasingly nearsighted. I would say that until at least 8 years of age, we will need to recheck a child's glasses prescription yearly to make sure that we are properly correcting the farsightedness and correcting the eye crossing.
As a child gets older then this, if the glasses seem to be correcting the eye misalignment well, we can start testing out what happens if we weaken the glasses prescription. Some children will begin to cross again once we weaken the glasses prescription. These are the kids who likely will need to wear glasses into adulthood. However, some children over time are able to maintain straight eyes without bifocals or glasses altogether.
Does having accommodative esotropia make my child ineligible for laser surgery (like LASIK) in the future?
Not necessarily. There are a number of factors that are taken into consideration when we think about laser surgery. These factors include the child's final prescription in adulthood (they may no longer be farsighted as the eyes continue to grow and become nearsighted over time), stability of their glasses prescription over years, the shape and thickness of the front of their eyes. I would recommend that any individual who is interested in laser surgery have a consultation with a reputable refractive surgeon to discuss the pros and cons of laser surgery prior to making an informed decision.
As with all my posts, the above information about accommodative esotropia is for educational purposes only. If you are concerned that your child has accommodative esotropia, please ask for a referral from your pediatrician or go see your local eye doctor for a formal eye evaluation.