What to Expect the Toddler Years (165 page)

Cross-eyes: When one eye (or both) wanders inward.

Wall eyes: When one eye (or both) wanders outward.

Strabismus.
What is it?
Cross-eyes—an inability to focus the eyes in unison, which may be present at birth (congenital strabismus) or which may develop later (acquired strabismus).
Who is susceptible?
Children with a family history of strabismus, but the condition can also occur when there is no family history. It occurs in children with normal vision and those with poor vision, but farsighted children are particularly vulnerable. They may develop strabismus in their third year, when they try so hard to focus on near objects that their eyes
cross.
Signs and symptoms:
Infants often appear cross-eyed for the first few months of life (pseudostrabismus), and once in a while during this time their eyes seem not to work in unison. But by the middle of the first year both of your child’s eyes should move right and left, up and down, and focus together pretty regularly. In about 4% of children, however, the lack of coordination persists. The wandering eye (or eyes) may drift inward toward the nose (cross-eye), or outward (wall-eye), or up or down; the misalignment may always be present, or it may come and go. The child may also rub or cover the weaker eye frequently, tilt the head to try to coordinate vision, and refuse to play games that require judging distances (such as catch). You can test for strabismus yourself at home (see illustration).
Causes:
Strabismus is often related to weakness in the muscles of one or both eyes (six muscles serve each eye). There may also be genetic factors or an association with other eye disorders (such as cataracts or farsightedness) or medical problems (such as Down syndrome or cerebral palsy), or very rarely, with other serious neurologic problems or eye disease.
Treatment:
Strabismus requires evaluation by a pediatric ophthalmologist; if strabismus develops
suddenly
, call your child’s doctor immediately. Except in cases in which the muscle imbalance is so minor that the brain can fuse the images (a condition known as phorias), treatment is imperative to avert amblyopia (see the facing page) and vision loss, and to prevent double vision and restore binocular vision (in which both eyes focus together). Treatment may include medicated eye drops to blur vision in the stronger eye or placing a patch over it (for short periods each day) to force the use of the weaker one; eyeglasses to equalize vision in both eyes; and sometimes, exercises to strengthen the eye muscles. In some cases, surgery may be needed to adjust muscle tension in one or both eyes, remove a cataract, or to correct another contributing condition.

To test for strabismus, position yourself face to face with your toddler. Shine a penlight at his or her eyes and note where the light reflects (see below).

If the reflection is centered on the pupils in both eyes (A), there is no strabismus—even if the eyes seem crossed. If the reflection is centered in one eye and off-center in the other (B), talk to the doctor about taking your child to see an eye specialist.

Amblyopia
.
What is it?
A condition affecting about 4 in 100 children, in which vision in one eye is better than in the other; the eye with the poorer vision becomes “lazy.” The brain, confused by the mixed signals and double vision coming in from the eyes, eventually shuts off the signals from the lazy eye and begins to use the better eye exclusively; the lazy eye then begins to lose its visual acuity.
Who is susceptible?
Children with eye problems (sometimes inherited)—such as strabismus, ptosis (see page 484), a cataract, or a refractive error, where vision is different in one eye than the other—or who have sustained an injury to the eye.
Signs and symptoms:
Sometimes, none that a parent can detect, which is why routine vision exams are absolutely essential.
Causes:
Most commonly, strabismus, unequal focus (refractive error), or a cataract.
Treatment:
Treatment for an underlying or associated problem will not cure the amblyopia, which must be treated separately. If it isn’t corrected by age five or six, vision in the weaker eye could suffer and loss of vision or even blindness in that eye could result. Treatment may include an eye patch, eye drops, and/or glasses. If an abnormality such as a cataract is responsible for the amblyopia, corrective surgery may be needed.

Ptosis.
What is it?
A condition in which one or both eyelids droop.
Who is susceptible?
Some children are born with ptosis (which is often inherited); others develop it later.
Signs and symptoms:
An enlarged, heavy, or drooping eyelid; occasionally, both eyelids are affected. In some cases, the lid totally covers the eye, inhibiting vision, or it distorts the cornea, causing an astigmatism.
Causes:
Generally, the eyelid droops because of weak muscles. Other causes are rare.
Treatment:
Ptosis requires evaluation and treatment by an ophthalmologist to prevent the development of amblyopia (if the child learns to depend on the eye with the normal lid, the lidded eye becomes lazy and its vision begins to deteriorate). When the problem is weak eyelid muscles, surgery (usually performed when the child is three or four) can strengthen them and give the lid a normal appearance. When another medical problem is responsible, treatment of that condition can cure the ptosis.

Other eye conditions (such as glaucoma, cataracts, and retinoblastomas [eye tumors]) are far less common in toddlers, but occur occasionally.

Learning that a toddler needs to wear glasses is generally a lot more traumatic for the parents than for the toddler. But it needn’t be, if you look at the positives. First of all, the glasses will help your toddler to see better. If they’re necessary, wearing them will help prevent the kind of developmental delays—and the diminished self-esteem—that often affects children who can’t see well. Secondly, starting to wear glasses at an early age is generally a lot easier than it is later on, when peer opinion becomes a major issue. Third, the need for glasses is far from uncommon. One in six children between the ages of three and sixteen wears them. In addition, a positive parental attitude about the glasses can go a long way in making a child feel good about wearing them (though, given “typical” toddler behavior, you can expect resistance, at least some of the time).

Shopping for glasses.
When choosing glasses, work with an eye specialist who is good with young children (ask your child’s doctor for a recommendation). Once you’re in capable hands, consider style, quality, and practicality in making your selection. Safety-glass lenses, while relatively scratch-proof, can break. And because they are also generally too heavy for toddlers, they often slide down the nose. Consider, instead, lenses made of regular plastic or of polycarbonate (a lightweight, strong, and shatterproof plastic, which reduces the risk of accidental eye injury). Because plastic lenses scratch easily, however, a scratch-resistant coating may be a good idea. The coating costs a bit extra and can crack, so be sure to ask if a warranty, which provides free replacement for a period of time if the coating becomes damaged, is available. No matter what kind of lens you choose, teaching your toddler careful care of the glasses from the very first day of wear may help them last somewhat longer; see page 486.

When selecting glasses consider, too, how they will be kept in place. For infants, elastic straps are usually substituted for the ear pieces. They hold the glasses in place and allow the child to lie on the side and roll around without discomfort or knocking the glasses off. They may also be practical for a very young toddler, although most year-old children do well with comfort cables (also called cable temples), which secure glasses by earpieces that curl around the ears rather than pressing against the head (
see illustration
). Flexible hinges are also a good idea, since they tolerate more abuse.

Since active toddlers aren’t able to keep ordinary eye glasses in place, their glasses must be specially designed. On infants and young toddlers, glasses are generally kept in place by an elastic strap (left) that substitutes for the ear pieces. Older toddlers do well with comfort cables, which curve around the ears (right).

Fitting the glasses.
Glasses can’t do their job unless they stay put, so good fit is essential. Because young children have fairly broad, flat nasal bridges and their glasses tend to slide down the nose, special attention is required when fitting the nose bridge. Rolled or flared nose bands (with or without non-skid silicone pads) may help keep glasses in place. The optician may have to drill “rocking” nose pads and arms into the nose bridge to obtain a good fit.