When should children get their first eye examination?
Infants and toddlers
A screening eye examination is part of the general physical examination that is given to very young children by their neonatologist (a doctor who specializes in treating newborn babies) or pediatrician. The doctor checks for:
- Visual fixation and tracking.
- Proper eye alignment (position).
- Problems on the outside of the eye.
- Pupillary light reflex (how the eye reacts to changes in light and darkness).
The doctor also checks for the quality of the red reflex (the red reflection when light is shined into the eye). An abnormal red reflex can be a sign of a problem in the eye, such as cataracts (clouding of the lens), problems with refraction (how well the eye focuses light), or even tumors.
If a problem is found during any part of the examination, the child is usually referred to a pediatric ophthalmologist, a doctor who specializes in diagnosing and treating eye conditions in children.
Vision screenings, such as eye chart tests, tell how well a child can see the form and details of objects (visual acuity). In children between the ages of three and five, visual acuity at a distance is tested using pictures, letters, or numbers.
Distance visual acuity is written as a fraction, such as 20/20. The number on top is the distance from the chart (most eye charts are read from 20 feet away). The number on the bottom is the distance at which a normal eye can read the smallest line on the chart. These screenings are one of the most effective methods for finding eye problems in children.
Some primary care doctors use a photoscreener, an automated machine with a camera that helps identify refractive errors and other eye abnormalities.
When does a child need further eye examinations?
Children are referred to an ophthalmologist if their visual acuity is:
- Less than 20/50 when they are three years old.
- Less than 20/40 when they are four years old.
- Less than 20/30 when they are five years old.
Children are also referred if there is a two-line difference between the eyes.
Children of any age should have their eye alignment checked using the cover test (each eye is covered, one at a time, to see if there is any movement in the other eye), or the stereo test (to check depth perception). If a child has any eye movement on the cover test or major errors on the stereo test, he or she should be referred to an ophthalmologist.
Children with a family history of significant childhood eye problems should be examined early in their lives for similar problems. A screening evaluation is completed by the pediatrician, but a detailed examination is best performed by the pediatric ophthalmologist.
What is a lazy eye and how is it treated?
"Lazy eye" (amblyopia) is a condition in which the child has poor vision in one eye, though the eye may appear to be normal. If this condition causes a child to use that eye more than the other one, he or she might develop poor vision in the eye that is not being used.
Amblyopia can result from crossed eyes (strabismus). The brain turns off the image coming from the crossed eye to avoid double vision, since this image cannot be superimposed on (placed over) the image coming from the other eye. Over time, the part of the brain receiving the image from the crossed eye loses the ability to see small targets, and vision is reduced in that eye. This condition is called strabismic amblyopia.
Amblyopia can also be caused by an uneven curve in the cornea (astigmatism), or from unequal errors of refraction between the two eyes (anisometropia). The child's brain will favor the clearer image coming from the eye with the lesser error of refraction; this can cause the child to use the other eye less, and leads to the condition anisometropic amblyopia. Blurry images from hazy structures in the eye, such as from the cornea or the lens of the eye, can also lead to so-called sensory deprivation amblyopia.
Amblyopia is treated by:
- Correcting the underlying eye problem; for instance, with eyeglasses; by straightening the eyes with surgery; or by clearing the hazy structure in the eye.
- Allowing the amblyopic eye to be used more by covering the other, better-seeing eye with a patch or by using eye drops that dilate (widen) the pupil of the eye.
Amblyopia can be reversed in the first eight years of the child’s life, but is best treated very early. The younger the child is at the beginning of treatment, the faster he or she can regain vision. Treatment is sometimes effective after eight years of age, as well.
When is strabismus surgery necessary?
Strabismus surgery is performed to straighten deviated (crossed) eyes and to allow the child to use both eyes together (binocular vision). In most cases, constant or very frequent deviations are best treated with surgery.
The most common exception to this is accommodative esotropia (the eye crosses inward), which is best treated with glasses. Children with this disease are very farsighted (hypermetropic) and their eyes cross inward as they focus to see clearly. Glasses can help relieve this focusing effort, which allows the eyes to remain straight.
On the other hand, children who are born with esotropia (the eye crosses inward) or exotropia (the eye crosses outward) usually need surgery to provide binocular vision. Because the problem in strabismus lies in the control of eye movements and not in the eye muscles, the results of surgery are not perfect in all patients. About 20 percent or more of patients need additional surgery, which can occur soon after the first surgery or in later years.
Children undergo strabismus surgery under general anesthesia in an outpatient setting (they go home the same day). They usually do not have any major pain after surgery, and go back to normal activities within a few days.
Do children get cataracts?
Children can get cataracts (clouding of the lens) in one or both eyes. Cataracts can be caused by many things. About one-third of cases are inherited from one parent who might have no symptoms, or who might have had surgery for a similar problem.
Trauma is the next most common cause of cataracts. Injuries to the eyes can hurt the lens and cause it to cloud. Other things that can cause the lens to cloud include metabolic, inflammatory, and infectious diseases, and long-term use of some medicines, such as steroids.
How are cataracts in children treated?
Cataracts that affect vision are best treated with surgery. The clouded lens is removed and may be replaced by an artificial intraocular lens (IOL) implant. The advantage of the implants is that they provide clearer, more normal-sized images on the retina than contact lenses or glasses.
What is nasolacrimal duct (tear duct) obstruction?
A nasolacrimal duct (or tear duct) obstruction is a condition in which tears cannot drain from the eye into the tear duct because something is blocking it. When this occurs, tears will “back up” and leak from the eye. The main reason this might happen is because a membrane at the end of the tear duct doesn’t open when the baby is born. Other causes include:
- Missing puncta (openings in the corner of the eye through which tears drain)
- Narrow tear ducts
- Tear duct is blocked by the nasal bone
How is nasolacrimal duct obstruction treated?
Most cases of nasolacrimal duct obstruction go away during the baby’s first year. Treatments can include:
- Tear duct massage
- Tear duct probing, in which a thin wire is passed through the tear duct to open it
- Antibiotic ointment or eye drops for the discharge from the eye. This treatment will not open the tear duct.