Your Child's Vision
My six-week old infant sometimes appears cross-eyed when he opens his eyes. Is this normal?
Studies have actually found that, on examination by pediatric ophthalmologist, less than half of the infants in the newborn nursery actually appear to have straight eyes. Many appear to have eyes that point outward (exotropia) and others appeared to cross in the inward direction (esotropia). Eye control is a developmental process that is learned during the first weeks to months of life. Therefore, in most cases, the diagnosis of misaligned eyes (strabismus) is not made until after 3-4 months age. The exception is with certain nerve palsies that inhibit lateral or vertical movement of one or both eyes, which are often evident prior to 3 months. Let your pediatrician know about your observation. If you or your pediatrician concerned, then you may be referred to a pediatric ophthalmologist for evaluation.
My 1-year-old had an eye screening with a photograph that indicated a possible problem. What does this mean?
Photographic screening is a technique whereby a pre verbal child is photographed with a special camera. The camera/computer evaluates the red reflex--the reflection of light from the back of the eye, i.e. the red eye that you sometimes see in nighttime photos. This technique can pick up refractive errors such as near-sightedness, far-sightedness, anisometropia (unequal amounts of refractive error) and even strabismus. Like any screening technique, it is not perfect. What it cannot do is provide a definitive quantitative result. To find out if your child needs glasses or not, an ophthalmologist will perform a complete exam in which your child's eyes will be dilated. Then, only after your child is fully dilated, your ophthalmologist can perform an accurate assessment of your child's refraction (eyeglass prescription).
One important fact to know and remember: if you assessed thousands of children between the age of birth to 2 years, on average they would have a refraction of +2.00 (mild far-sightedness). This is completely normal. Mild age-appropriate far sightedness does not cause blurry vision in this age. It does not cause "eye strain" in this age. It absolutely DOES NOT need glasses correction in this age. With growth, the eye lengthens and the far-sightedness normally decreases towards emmetropia (no refractive error) over the next few years. NOTE: If your child has a prescription for glasses that are less than +1.00, reportedly to "help with reading," it would be advisable to see a pediatric ophthalmologist for a second opinion.
My 4-year-old child seems to have good vision, but he could not read the eye chart with his right eye at pediatrician's office. Could this be something serious?
There are hundreds of potential causes of decreased vision in a child. Fortunately, "serious" sight or life-threatening conditions are rare. However, to rule these conditions out, a complete, dilated exam by an ophthalmologist is necessary. The number one cause of preventable vision loss in America is amblyopia. Amblyopia, by definition, is decreased visual acuity in one or both eyes despite normal anatomic structure of the eye or eyes. There are three causes of this condition:
- Obstruction of the visual pathway by a congenital cataract, drooping eyelid, or other conditions--can cause amblyopia in one or both eyes
- A misalignment of the eyes (strabismus) in which the child uses one eye and disregards the other--causes amblyopia in one eye
- Extremely high refractive error (near-sightedness, far-sightedness, or astigmatism) in both eyes or unequal refractive error of the two eyes in which the child uses one eye and disregards the other--causes amblyopia in one or both eyes
In short, a child's visual system is in a state of development from birth to about age nine. The neural pathways from the eye all the way back to the visual cortex of the brain are continually forming during this time. Any condition that obstructs or blurs the visual image received by the brain from either eye leads to a failure of these pathways to form properly. Any condition, such as crossed eyes (strabismus) that leads the brain to use only one eye and disregard the other also leads to a failure in these pathways. The result is an eye that appears normal on exam, but has decreased visual acuity--possibly as mild as 20/25, but sometimes as profound as 20/400 or worse.
Is amblyopia treatable?
Yes, amblyopia is treated by first treating the underlying cause:
- treating an underlying condition such as cataract or drooping lid
- muscle surgery (strabismus surgery) to realign the eyes
- eyeglasses to provide equally clear image to each eye
Then, if any vision deficit still exists, the weak eye can be strengthened by patching the better eye, which forces the brain to use the weak eye, thereby stimulating the neural pathways from that eye to form. In some cases, an eye drop that blurs the better eye can be used in place of the patch. After the vision improves, the patching is tapered down, and the vision is closely monitored. Patching only works before age 8 or 9. After age 10 there is usually very little response to therapy.
How would I know if my child has amblyopia?
Very often you will not know. There are often no outward signs that a child has decreased vision in one eye because the other eye is often 20/20.
How is amblyopia diagnosed initially?
There are very successful screening programs in place in the schools, health departments and pediatric practices to detect possible problems while they are still treatable. These screening techniques, while not 100% perfect, are very successful and extremely cost-effective. The majority of amblyopia cases are first uncovered there. If there is any questionable result on a screening test, or if there is any sign of crossed eyes, squinting, head turning, or other obvious or suspicious abnormality, a complete exam is warranted as soon as possible, regardless of the child's age. During this exam, all the other possible causes of decreased vision in a child will be ruled out before a diagnosis of amblyopia is arrived at. For this reason, it is very important that your child is seen by a trained ophthalmologist with the knowledge, skill and equipment available to rule out these other possibly sight and/or life-threatening conditions.
My child has never had a problem on vision testing. When is it recommended they be seen for an eye exam?
The American Academy of Ophthalmology recommends a well child have a full, comprehensive eye exam between the age of 3 and 5.
|