Contact lenses have become very popular in our society. Parents are now asking for their very young child to be fitted with contact lenses. Despite their popularity, contact lenses are most often not medically necessary. They are a device of which many people recognize the benefits. Unfortunately, most contact lens wearers forget the risks associated with contact lens wear. According to a recent publication, contact lens related problems account for more emergency room visits in children than any other condition.

Soft contact lenses sit on the eye’s cornea and extend just past the limbus to the conjunctiva. They block some of the oxygen reaching the cornea while correcting the optics of the eye to allow it to see clearly. The materials and design of contact lenses have improved greatly over the last 15-20 years. They are now more permeable to oxygen, which is healthier for the eye. Despite these advances, we still frequently see contact lens related problems in our office.

These problems often stem from poor contact lens hygiene. No matter how well we educate our young patients on the proper care of their contact lenses, they often pick up the bad habits of their peers or even of their parents. The contact lens related problems can range from mild, temporary conditions to severe, sight-threatening ones. Corneal ulcers and infections can permanently reduce the best corrected visual acuity of an eye, especially if not treated immediately. Corneal abrasions, or scratches to the eye, often occur as a result of trying to remove a lens that has adhered to the eye. Giant papillary conjunctivitis can result from contact lens wear and causes redness and discomfort. These are just a few common examples of problems resulting from contact lens wear.

Any parent who is considering contact lenses for her child should evaluate his general hygiene and responsibility level. If a child is begging for contact lenses and has adequate general hygiene and is responsible, then contact lenses should be considered. Keep in mind that there is an expense associated with contact lenses. Contact lenses have different replacement schedules. This must be followed as prescribed by your eye doctor, so anywhere from 12-365 contact lenses per eye per year may need to be purchased. Also, the cleaning system that is prescribed should be followed. A properly cared for set of contact lenses should require a new bottle of contact lens solution every one to two months. The contact lens case should be replaced each time a new bottle of solution is purchased. Once you’ve decided that you’re ready to deal with the expense and supervision of contact lenses, then you should talk to your child’s eye doctor.

In our office, we want our patients to go home with contact lenses that they are capable of inserting and removing on their own. Parents are not with their children in school to help with the contact lens if a problem arises. Every child should be able to take care of contact lenses independently, but with a parent’s supervision. Children are taught how to care for their contact lenses before leaving the office with them. It is recommended that parents, especially if they are contact lens wearers, listen in for a refresher in proper contact lens care.
Important: Not following the contact lens hygiene instructions exactly as prescribed puts you at a high risk of developing contact lens related eye problems that can be sight threatening. Please do not assume that because you or someone you know has been lucky enough to never have had a problem despite not exactly following the prescribing doctor’s recommendations that your child can also inadequately care for his contact lenses and be just as lucky. Remember that contact lens related eye problems are a common reason for children to visit emergency rooms. If properly cared for, your child can enjoy a lifetime of the benefits of contact lens wear.

Michelle L. Wertelet, OD, FAAO

That depends on the vision or more correctly, visual acuity, of the eye. A quick explanation of terms may help to make this topic easier to digest.

Amblyopia-decreased vision, usually in one eye, that happens when the eye is not being used by the brain. The eye itself is normal and healthy, with few exceptions.

Strabismus-a general term for eyes that are not straight. One eye can be turned in, out, up, down, or a combination.

Anisometropia-a significant difference in glasses prescription between the two eyes.

“Lazy eye” actually refers to amblyopia, which is the most common cause of decreased vision in children. An eye can be amblyopic due to strabismus, anisometropia or visual deprivation. Unfortunately, in our culture the term lazy eye has become synonymous with strabismus. Lazy eye does not always mean strabismus. Lazy eye always means amblyopia. The sound eye is the eye without amblyopia.

For example, Patient A has strabismus. His left eye is always straight and his right eye is always crossed in. The right eye probably has amblyopia because it is not being used. The left eye is doing all of the work and the brain is forgetting about the right eye. Patient B also has strabismus. She switches eyes. That is, sometimes the left eye crosses, sometimes the right eye crosses. Patient B probably does not have amblyopia (does not have a lazy eye) because both eyes are being used (although not at the same time).

In the case of anisometropia the eye with the stronger prescription will have amblyopia (lazy eye) even if both eyes are perfectly straight! The amblyopic eye will send a blurred image to the brain and the sound eye will send a much clearer one. A blurry image is not very useful and the brain stops using the eye.

Deprivation is caused by anything that blocks the visual axis in an infant or young child. Causes are cataract, severely drooped eyelid, tumor, or a cloudy cornea.

How do we treat lazy eye (amblyopia)?

Simply put, the goal of amblyopia treatment is to make the brain start using the eye. A lot of our brain function works on the “use it or lose it” principle and amblyopia treatment is no exception. Glasses are usually necessary to make a clear image on the retina and may be the only required treatment. The prescription must also be correct. In the majority of cases a cycloplegic refraction (done with dilating drops) must be done to ensure the proper prescription.
Patching is now needed. Wearing a patch over the good eye (while still wearing glasses) for a few hours daily as prescribed will force the brain to use the lazy eye. With time the visual acuity will improve.

Atropine eye drops have been shown to be an effective alternative to patching. This is sometimes referred to as a “liquid patch”. The principle is the same. Atropine is used on the good eye once daily to make the vision blurry at near. When child is playing a handheld game or doing homework he/she will start relying more on the amblyopic eye. Atropine will not work if the visual acuity at the beginning of treatment is not close enough. For example: the right eye sees 20/20 and the left eye sees 20/150. If Atropine brings the right eye to 20/80, the child still will use the right eye predominantly because this eye still sees better.

Amblyopia treatment is more effective in younger children. The visual system is still maturing up until the age of 8-10, though some newer data suggest that amblyopia may be treated in some cases up until the early teenage years. Once visual maturity occurs the eyes and brain are essentially “hard wired”. If the recommended treatment was not followed for many years and a 12 year old has only 20/100 vision, he’s unfortunately stuck with 20/100 vision. Glasses, contacts, or refractive surgery are unlikely to help him see better at that point.

Some children must be followed more closely than others. It is important to keep your child’s appointments with his/her ophthalmologist or optometrist, especially while the visual system is still maturing. Only by working together can we help your child reach his/her full visual potential.

Eric A. Pennock, MD

Color vision deficiencies can be congenital or acquired. There are acquired color vision deficiencies that can occur later in life from conditions that affect the lens, retina, or optic nerve in the eye. I am going to talk about the color deficiencies that are congenital in nature—the type that a person is born with.

The inherited nature of color vision deficiencies causes these to run in families. The gene for the color vision abnormality is found on the X chromosome. It is recessive, which means that when combined with a normal X chromosome the person has normal color vision. Females have two X chromosomes. This is why congenital color vision defects are estimated at less than 1 % of females. Males have one X and one Y chromosome. Approximately 8 % of males are affected by a color vision deficiency. Oftentimes, a little boy’s mother is not affected, but her father and/or brothers may have a color vision deficiency. Two boys from the same parents can be affected differently; in other words, one may have normal color vision while the other has a color vision deficiency.

Congenital color vision deficiencies do not change over time. A baby born with it will always be affected by it. The good news is: that baby will easily adapt to how he perceives colors. Identifying a color vision defect early can have a positive impact on a child’s education. By knowing that a child does not differentiate colors normally, a teacher and parent will be able to ensure that child is not graded based on color.

Color is perceived by structures called cones, which are a part of the retina. There are cones responsible for seeing red, green, and blue. Color vision deficiencies occur in different degrees. Some people’s color perception is only mildly affected, while other people’s perception is more severely affected. For example, in a person with a more severe defect the red cones may be missing or may not function at all while a person with a mild defect may have red cones that almost function normally. This makes it difficult to describe what a person with a color deficiency sees. I’ve attempted to simulate three common color deficiencies. The red/green deficiencies are much more common, while the blue/yellow deficiencies are rare.

To best answer this question, I first need to explain a little about nearsightedness, farsightedness, astigmatism, and a little about how our eyes see. The eye gathers light from the objects in our environment. First, the light passes through our cornea- the clear front surface of our eye. The pupil then dilates (gets bigger) or contracts (gets smaller) to allow enough light to enter through our eye. After the light passes through the pupil, it then passes through another clear structure called the lens. Finally, the light comes to a sharp focus on our retina. Our retina then sends signals to our brain through our optic nerve to interpret the focused light as an image of the object we’re looking at. The cornea and the lens are responsible for focusing the light directly on to the retina. If the power of the cornea and lens are too strong or too weak, the light does not come to a sharp focus on the retina resulting in blurry vision.

Myopia is the technical name for nearsightedness. It means that you have difficulty seeing things far away. In a nearsighted eye, the power of the cornea and lens are too strong. The sharp focus occurs in front of the retina. In other words, the eye is too long for its focusing power.

Hyperopia is the technical name for farsightedness. It means that the focusing power of the cornea and lens are too weak. The light is focused behind the retina—in effect, the eye is too small for its focusing power. In order to make the image clear the eye has to accommodate, or focus more. Children have a tremendous ability to accommodate their eyes, so they can often still see clearly if they are mildly farsighted. However, if the amount of farsightedness is too great then they will have a blurred image. It is this ability to accommodate our eyes that allows us to see clearly up close. Unfortunately, as we age we lose our ability to accommodate and have trouble seeing at near distances. This is why bifocals or reading glasses help—they do that focusing for us.

Astigmatism occurs when the cornea of the eye is shaped more like an egg than like a ball. This causes the light coming into the eye to focus in two places instead of one, resulting in a distorted image.

Glasses change where the light focuses. It makes the light come to one sharp focus directly on the retina. Glasses that correct for hyperopia have a “plus” power effectively increasing the power of the eye to make the light focus on the retina. Because a myopic eye is focusing the light too much, the glasses decrease that power and have a “minus” power.

If you think about a hyperopic eye being too short for where the light focuses and a nearsighted eye being too long for where the light focuses, you can better understand why children’s prescriptions change so frequently. Just as a child’s pants become too short and shoes become too small because of their growth, the eye changes as well often making the eye longer. This is why the hyperopic prescription can improve over time and the myopic prescription increases over time. Because children grow at such a rapid rate as compared to adults, their prescriptions change much more frequently.

Michelle L. Anderson, OD

 From our experiences at the eye doctor’s office, we know that we are asked to read letters on an eye chart and then have to answer the dreaded, “Which is better, one or two?”  We never know if we’re answering the eye doctor correctly, but somehow he or she comes up with a prescription for glasses and we can see out of them.

 I often have parents ask me how their young child can have an eye exam.  They are worried that their child won’t name pictures on the eye chart or won’t be able to tell me whether one is better than two.  These are legitimate concerns based on our experience.

 Fortunately, an eye exam can be performed relying on objective measurements-ones that do not rely on a child’s response.  If a child is too young or too shy to name pictures for us, then we make other observations about their visual behavior.  We check the alignment of the child’s eyes to make sure that both eyes are working together appropriately.  We also thoroughly examine the health of the child’s eyes to make sure the eyes are healthy and there is nothing present that would cause the child’s vision not to be perfect.  We use dilation drops to enlarge the child’s pupil so that we can observe the health of the insides of the eyes.  These dilation drops also serve another purpose.  They have a cycloplegic effect, which keeps the child’s eyes from focusing.  This is why the dilation results in extra sensitivity to light (enlarged pupils) and blurry vision (inability to focus).  By performing a refraction using a retinoscope (a special type of flashlight), we can determine the extent of nearsightedness or farsightedness in each child.  This is why we don’t have to ask the child to pick the clearer lens.

 As children get older, we still perform these objective measurements.  By putting the child’s responses together with our objective findings, we have more information that supports our diagnosis and management for that child.  Our objective measurements also help us during those times when Mom or Dad suspects their child just wants glasses but can actually see well.  Overall, your child’s eye exam will seem different from what your experiences are at the eye doctor’s office.  However, the same things are being evaluated in a way that is tailored to children. 

 -Michelle L. Anderson, OD

4/29/10