How do you measure strabismus (eye misalignment)?

Strabismus can affect both children and adults, and occurs when the eyes are not aligned. As you may know, the misalignment can be very small, very large, or anywhere in between. By using prisms -- just like the prisms you learned about in science class -- we can measure the amount of misalignment, which helps to determine what is causing the strabismus, whether it's getting better over time, and how best to treat it.

Prisms come in different sizes, allowing us to measure eye misalignment.

Using prisms to measure any strabismus detected on the eye exam is a critical component of the eye exam. Although the prisms are held near the eyes, they don't hurt in any way, and it's possible to get useful measurements with prisms for the majority of patients. As your child grows, our ability to measure their eye misalignment will likely get even better, too.

When is strabismus surgery needed?

For patients both young and old with eye misalignment, or strabismus, surgery can often be performed.

Some reasons to perform strabismus surgery include the following:

This child has a dissociated vertical deviation (DVD), a type of strabismus in which one eye will periodically drift upward, while the other eye stays put. Surgery can be curative.

1. To help the eyes work together and promote the development of good binocular vision, or depth perception. This is most important for young children, during the critical period of visual development that occurs in the first few years of life.
2. To eliminate double vision. This is usually more of a concern for adults, as children with strabismus typically ignore the second image and don't have double vision.
3. To minimize any abnormal head turn or tilt that a patient might prefer, either consciously or subconsciously, to try to minimize their strabismus. These abnormal head postures, if present chronically, can become physically and socially disabling.
4. To improve the ability to interact with others. There is an unfair stigma that often exists in society with regard to people with eye misalignment. I love helping people get their eyes straight, not only because it helps their vision, but also because it helps them gain confidence in their social interactions.

What to expect during your child's eye exam

This short video, created by the American Association for Pediatric Ophthalmology & Strabismus, explains what to expect during a child's eye exam with a pediatric ophthalmologist, including answers to questions such as:

• How can you measure vision in a young child?
• How long will it take?
• Why are dilating drops necessary?
• How do you know if they need glasses?

Is strabismus surgery covered by insurance?

Patients commonly wonder if eye muscle surgery to realign the eyes and fix strabismus is covered by insurance.

In a word, yes!

Virtually all health insurances, both private and state-sponsored, cover strabismus surgery, as it is reconstructive, not cosmetic. Our office will be sure to verify this with your insurance provider prior to the surgery date. If there will be any anticipated out-of-pocket costs, we will let you know beforehand.

I'm not sure how my child will do during the eye exam...

Shy? Upset? Scared? It's okay! We make the eye exam fun.

Let's admit it -- the doctor's office can be a scary place when you're a kid. Tall people walking around in white coats, nurses coming at you with needles that they swear "won't hurt a bit," doctors poking you with all sorts of weird equipment.

I understand that. Parents are often nervous about how their child will do during the eye exam, whether because it's a new thing, or because of prior negative experiences, or because of medical conditions their child has, or simply because they know their children.

Honestly, one of my favorite things about my job is winning over a child who is initially hesitant, afraid, upset, or downright angry about things. My staff and I do our very best to make things as fun and angst-free as possible for our patients and their families. We turn eye exams into games, talk softly, try not to use scary words, and patiently work with our little patients to not only get the information that we need, but to also make it a good experience for them.

In short, whether your child is shy, angry, fearful, "difficult" (a term I don't like), or special for any reason at all, I can't wait to meet them and help take care of their eyes.

How do I know if my child needs glasses?

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Adult patients can sit at a phoropter to have their refractive error -- need for glasses -- measured.

If your child doesn’t seem to see well — whether they are holding things very close to see them, or complaining that their vision is blurry, or if something just seems “off” — bring them in for an eye exam!

Determining whether glasses are needed is part of any complete eye exam, and includes measurements of a child’s current visual abilities as well as their “refractive error.”

What is “refractive error,” you ask? Well, it’s the medical term for how “out of focus” the eyes are. Our eyes have a tremendous ability to focus, but it is rarely perfect. Most everyone has some degree of refractive error as a result. For the majority of people, this “out of focus” is minimal and not enough to need glasses. For others, it is enough to make vision blurry, and glasses are needed. Of course, not every eye problem is due to refractive error, so glasses don’t fix every possible type of eye problem.

The cool thing about refractive error is that, like a shoe size, it can be measured, even for kids who aren’t old enough to cooperate very well or even speak!

Unlike adults, who can easily sit behind a device called a phoropter (see photo) and reliably tell you whether "Number 1 is clearer" or "Number 2 is clearer," children have their glasses prescription measured in a different way.

By using a handheld device called a retinoscope, the eye doctor can accurately measure not only whether a child needs glasses, but also what the prescription should be.

The physician turns on the retinoscope, generating a bar of light, and then looks at each eye, moving the bar of light up and down and side to side. This creates a reflex of light within the patient's eye. Handheld lenses -- just like the ones in the dials of the phoropter -- are held up in front of the patient's eye, and the physician looks for the light reflex to stop moving as he or she moves the bar of light. The lenses that allow this light reflex to stop moving are used to determine the patient's prescription. In the hands of an experienced examiner, this method of prescribing glasses is very accurate.

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A standard retinoscope, used to measure glasses prescriptions in children.

Why are dilating drops necessary?

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Cyclopentolate is the standard dilating eyedrop used for children's eye exams.

Great question! Although dilating drops do add some additional time to your visit, and are not any child's favorite part of the exam, they wear off within one day, only sting a little for a minute or so, and are critical to a pediatric eye exam for two reasons:

1. They allow the ophthalmologist to examine critical eye structures like the optic nerve and retina, which are very hard to see otherwise.
2. They allow for an accurate determination of the child's refractive error. Refractive error refers to any trouble with the focusing system of the eye, and examples include myopia ("nearsightedness"), hyperopia ("farsightedness"), and astigmatism.

How long does an eye exam for my child take?

During their first clinic visit, I will perform a complete eye examination for your child. This includes things like checking their vision, their eye alignment, and the -- many! -- different structures within the eyes. It also includes putting dilating drops in the eyes, which allow me to examine the optic nerve and retina, and to get an accurate refraction, checking for nearsightedness, farsightedness, or astigmatism. 

Dilating drops for children take about 30 minutes to work. During this time, your child is free to play in our pediatric waiting areas, which are stocked with toys, movies, and the like.

For a visit in which we use dilating drops, plan on being in our office for about 1.5 - 2 hours. Because dilating drops are typically only needed annually, future visits are often shorter, on the order of 45 minutes.

Your time is important to us, and our team will do its best to provide thorough yet timely care.