Article Date: 2/1/2002

Continuing Education
Children: An Untapped Population of Contact Lens Wearers
As the older end of the contact lens-wearing spectrum increases with better presbyopic designs, remember the younger end as well.
By Jeffrey Walline, O.D., M.S.

Contact lenses have been primarily aimed at attracting young adults. Recent advances in bifocal contact lens designs expanded the contact lens-wearing population toward the older end of the spectrum, and tinted and logo contact lenses expanded the contact lens-wearing population toward teen-agers. One relatively untapped population of potential contact lens wearers that remains is children younger than the teenage years.

Many eyecare practitioners are leery of fitting children younger than 13 years because they feel that younger children are not mature enough to handle the responsibility of caring for contact lenses. At least two studies and one clinical report have shown that children younger than 13 are able to adapt to contact lens wear and understand the care regimen necessary to maintain healthy eyes.

Indications for contact lens wear vary widely among young children. The most common reason for contact lens wear in children is correction of refractive error. However, contact lenses may also be used to treat binocular vision anomalies, potentially slow the progression of nearsightedness, treat amblyopia and improve the cosmetic appearance of disfigured eyes. In addition to the visual benefits for children, contact lenses may be more convenient than spectacles for athletic girls and boys, children may feel that contact lenses are more comfortable and cosmetically appealing than spectacles, and contact lenses may be more cost effective for children who break their glasses on a regular basis.

REFRACTIVE ERROR

Children who are aphakic, myopic, hyperopic or anisometropic may benefit from contact lens wear.

Aphakia

Congenital cataracts are detected in 1.7 out of every 10,000 children born during a given year in the United States. Intraocular lenses (IOL) are typically not implanted because eyes grow dramatically during childhood. The resulting high refractive error affects the visual experience of the infant and may result in amblyopia. Spectacles are a standard treatment option for aphakic children, but many children do not tolerate spectacles and may repeatedly remove them. Inconsistent refractive error correction may not be sufficient to prevent the onset of amblyopia. Contact lenses provide an excellent treatment alternative for aphakic children because they are cosmetically more appealing, eliminate heavy glasses and are more difficult for young children to remove on their own. Many practitioners prefer a specific brand of aphakic extended wear contact lens for children, such as the Silsoft silicone lens (Bausch & Lomb).

Your 2- to 3-year-old patients may be very opposed to contact lens application, and they are often strong and agile enough to make the process very difficult (Figure 1). This necessitates extended wear contact lenses that may be removed by the parents or during monthly visits to the eyecare practitioner if the child is extremely uncooperative. To facilitate the application and removal process, the child's arms and legs may be wrapped in a blanket and the contact lens should be inserted or removed while a parent holds the child as still as possible. After the application process is complete, you will have a happy, young child (Figure 2).

Figure 1. Use a blanket to wrap an uncooperative child during contact lens insertion and removal. (Photo courtesy of Dr. Karla Zadnik)

Myopia

The onset and progression of myopia typically occurs before age 15 or 16 years. Approximately 15 percent of the United States population becomes myopic before entering high school. A standard treatment for myopia in children is spectacles, but contact lenses may also be prescribed. Contact lenses for myopic children provide a convenient mode of refractive error correction while offering cosmetic appeal to young, self-conscious individuals. Soft contact lenses, especially disposable, may be the treatment of choice for children who wish to wear contact lenses occasionally, such as only for sporting events. The initial adaptation time is generally shorter for soft contact lenses, and occasional wear of rigid gas permeable (RGP) contact lenses may not provide optimal comfort.

Children with hand-eye coordination difficulties and children who want to consistently wear contact lenses may benefit from wearing rigid gas permeable contact lenses. RGP contact lenses do not invert, and they are easier to clean and handle. RGP contact lenses may also slow the progression of myopia in children. Most previous studies of the effect of rigid contact lenses on myopia progression in children have shown that they decrease the progression of myopia by 50 percent or more (Table 1).

Pathological myopia typically develops at a very young age and progresses throughout childhood. Extremely myopic children who wear spectacles may suffer from reduced peripheral vision, eyelashes that contact the back of the spectacle lenses and image minification. Contact lens wear may help each of these side effects of spectacle wear for high myopes.

 

TABLE 1: Mean Annual Rate (D/year) of Myopic Progression for RGP Wearers and Spectacle Wearers Participating in Previous Myopia Control Studies

RIGID CONTACT LENSES SPECTACLES
Baldwin (1969) ­0.53 ­0.45
Stone (1976) ­0.10 ­0.35
Perrigin (1990) ­0.16  ­0.51
Khoo (1999) ­0.42 ­0.78

Hyperopia

Approximately six percent of 6- to 8-month-old infants have hyperopia greater than +3.50D. These infants are up to 13 times more likely than infants with low hyperopia or emmetropia to develop strabismus by age 4, and they are six times more likely to have amblyopia. Refractive correction of hyperopic children will not alter their emmetropization process, and it may prevent the onset of accommodative esotropia, so refractive error correction is indicated for young hyperopic patients.

Hyperopic spectacles are often uncomfortable due to the weight of the lenses, and children may feel that the magnification caused by hyperopic spectacles makes their eyes look "funny." Contact lenses are available in all modalities for hyperopic children, including rigid contact lenses, traditional soft contact lenses and disposable soft contact lenses.

Figure 2. Happy young patient following contact lens insertion. (Photo courtesy of Dr. Karla Zadnik)

Anisometropia

Approximately three percent of young children are anisometropic by 1.00D or more. Anisometropia is more common in people with high refractive error. The side effects of optical correction with spectacles is more pronounced in patients with anisometropia and high refractive errors because the prismatic effects of spectacle lenses differ when the patients are not looking in primary gaze. This may cause headaches, eye strain or double vision. Contact lenses can eliminate these symptoms because the optical center of the lens translates more closely with the eye movements, thereby reducing prismatic differences between the two lenses.

Anisometropia may also cause vision problems due to a difference in retinal image size produced by lenses of varying power. In order to decrease the difference in retinal image size between the two eyes, anisometropia that is not caused by a difference in axial length, i.e. refractive anisometropia, should be corrected by contact lenses. Refractive aniseikonia is more likely than axial aniseikonia to be reduced or eliminated by contact lenses. If an anisometropic patient has symptoms indicative of aniseikonia and the keratometry readings differ by an amount close to the amount of anisometropia, contact lenses are likely to reduce or eliminate the symptoms. Patients with anisometropia typically are able to be optically corrected with standard contact lens fitting procedures and do not require custom lenses.

Figure 3. Extremely myopic girl with spectacles that are heavy, limit peripheral vision, minify the retinal image, are cosmetically unappealing, and contact the eyelashes.

BINOCULAR VISION ANOMALIES

Children with accommodative esotropia or convergence excess may benefit from contact lenses. The first step in correction of binocular dysfunction is correction of refractive error. Nearly all cases of refractive error correction associated with binocular anomalies can potentially be treated with contact lenses.

Accommodative Esotropia

Children with uncorrected hyperopia or a high accommodative convergence to accommodation (AC/A) ratio may develop accommodative esotropia, typically between ages 2 and 7. Contact lenses may improve cosmesis, provide better comfort, yield better optics and improve compliance vs. spectacles. Contact lenses may also improve acceptance of plus power for hyperopic subjects because the accommodative demand is less for hyperopic patients wearing contact lenses vs. spectacles.

Fit the patient with contact lenses to optimally correct the refractive error, and examine the binocular status while the patient is looking at distance and at near. This should be repeated after one week of contact lens wear and two to three weeks later. If a tropia still exists at near, bifocal contact lenses or glasses for reading should be considered to eliminate the loss of binocular fixation.

Convergence Excess

A 10-year-old boy with convergence excess wished to wear contact lenses instead of spectacles with progressive addition lenses. His cover test results while looking through single vision contact lenses was orthophoria at distance and 17 (prism diopters) esophoria at near. We explained the benefits of bifocal contact lenses compared to a pair of reading glasses. The boy and his parents were interested in bifocal contact lenses.

While wearing single vision contact lenses and looking through a +1.50D addition with trial lenses, he was orthophoric at near. We fitted him with Acuvue Bifocal (Vistakon) contact lenses with a +1.50D addition. His phorias while wearing the contact lenses were ortho at distance and 8 to 10 esophoria at near. A +2.50D addition contact lens reduced the near esophoria to 4 to 6, which was confirmed two weeks later. One year later, the patient had no visual or asthenopic complaints, but we lowered the power of the addition to +1.50D. The near phoria with a +1.50D addition bifocal contact lens was 2 esophoria.

PROSTHESIS

Prosthetic contact lenses for children may be used in some cases of corneal scarring or amblyopia.

Corneal Scar

Corneal scars may lead to visual disability and psychological scars for children if not properly managed. Standard fitting sets for prosthetic contact lenses from many manufacturers are available. Contact lenses may also be custom made to match the other eye or to alleviate unique problems that a patient may encounter.

Opacification of the cornea in infancy may be due to congenital glaucoma, birth trauma, congenital endothelial or stromal dystrophy, posterior polymorphous dystrophy, Peter's anomaly, metabolic abnormalities, interstitial keratitis, herpes simplex, corneal ulcer, corneal dermoid or sclerocornea. Occasionally visual rehabilitation may be possible, but non-seeing eyes may require contact lenses simply to improve cosmesis.

Peripheral scars may be hidden with colored contact lenses that have a clear pupil (Figure 4). Central scars may require an opaque pupil to improve cosmesis in a non-seeing eye (Figure 5).

Figure 4. Prosthetic contact lens with a clear pupil.

Amblyopia

Although it is often a treatable condition, amblyopia is a leading cause of reduced visual acuity in children under the age of 8. One of the most important factors in the successful treatment of amblyopia is occlusion. Typical methods of occlusion include black "pirate" patches, skin-colored adhesive patches or stickers on top of spectacles. All of these methods are noticeable and relatively easy for a young child to remove.

Contact lenses provide an alternative method of patching, especially for children who remove their patches or children who require longer periods of patching. Two types of contact lenses may be used for patching: an opaque pupil contact lens or a contact lens with much greater plus power than is necessary for refractive correction.

The frequency and duration of the patching regimen dictate the type of contact lenses that are necessary. Spherical disposable contact lenses are typically the method of choice because of their cost efficiency and fitting diversity when using the overplussing treatment mode. However, occasionally a prosthetic contact lens with an opaque pupil or an extended wear contact lens may perform better due to special circumstances, if indicated.

TIPS FOR FITTING CHILDREN

New experiences can be very traumatic for young children because they do not know what to expect. Anxiety is a major psychological factor that can negatively impact contact lens adaptation. In order to alleviate some of the concerns a child may have, you should tell the child exactly what to expect. A child can often tell when a doctor stretches the truth or hesitates with uncertainty. Either of these factors can add to the child's concern and decrease the likelihood of contact lens adaptation. You should also tell the child what you are doing while you are doing it. This will decrease the time the child has to think about the potential consequences, the chair time used to fit the child and the time the child has to become anxious. You will often find that the second contact lens is much easier to apply than the first contact lens because the child knows that the lens can be applied easily and does not hurt.

Children may writhe when you approach their eyes with contact lenses. If you allow the child to wiggle, the fitting process may take longer and the child may become more anxious. You should give the child a target on which to fixate, firmly hold the head still using the back of the chair and a gentle grasp with your hands, and tightly hold the eyelids open (Figure 6). Let the child know that the contact lens is on the eye as soon as soon as possible; the child will often be amazed how easy it was to put a contact lens on the eye. A quick lens application will put the child at ease immediately and will show him or her that contact lens application is not difficult.

Topical anesthetic should also be used at both the fitting and dispensing visits of RGPs. One drop in each eye during each visit has been shown to be beneficial to the overall success rate of adult contact lens wearers. Many practitioners do not like to put an anesthetic drop in the patient's eye at the dispensing visit due to the liability of a patient with no corneal sensation wearing a contact lens. However, application and removal training takes more than 15 minutes, so corneal sensation will return to normal levels by the time the child leaves your office.

Children hate eye drops. In order to avoid putting an additional drop in the eye, place the anesthetic in the contact lens prior to application. If the lens is too heavy with a drop in it, you can displace most of the drop by placing your finger in the lens. The child will still receive the benefit of the anesthetic eyedrop, which will improve the child's temperament and your ability to evaluate vision and lens fitting with fluorescein.

Figure 5. Prosthetic contact lens with an opaque pupil. (Photo courtesy of Dr. Karla Zadnik)

A spherical refraction performed over the rigid contact lens is not necessary on a regular cornea. The power of an "on K" rigid contact lens should be equal to the spherical component of the manifest refraction referred to the corneal plane. Lacrimal lens compensation should be made for lenses fitted flatter or steeper than the K. You can reliably order the initial lens power based on this theory in order to save time and hassle.

When you check the refraction over the lenses at the dispensing visit, you may find that the child accepts +0.50D to +1.00D of sphere power. When this happens, ask the child to blink hard, then recheck the power. You will probably find that the child will no longer accept the plus power. Even if the child accepts up to +1.00D over the contact lens power, recheck the power in one week before you change the contact lens power. One week after the dispensing visit, the child's visual acuity will probably decrease with a +0.25D over-refraction.

Children regularly lose or break at least one lens within the first two weeks, but they become much more adept at handling contact lenses and contact lens replacements become much less necessary with time. We order a spare pair of contact lenses for the initial dispensing because they nearly always are the correct parameters when the corneas are healthy, and the adaptation time is reduced when a child loses a lens and has a spare lens to wear immediately.

Occasionally a successful contact lens wearer may experience a traumatic situation such as applying the lens without rinsing off all of the soaking solution. This single event may cause a mental block that is very difficult for the child to overcome. The child may refuse to apply the lenses because he or she fears the lenses will hurt again. More often than not, the parents tell the child many times without success to try applying the lens again. The eyecare practitioner's reassuring affirmation and individual coaching often helps the child overcome his or her fear. If that fails, dispense anesthetic to the parent for temporary use.

A child who tries to apply a contact lens but can't seem to get the contact lens on the cornea may also benefit from topical anesthetic. In order to decrease the potential for abuse, you should explain the potential side effects to the parent and allow only the parent to instill the drops. Tell the child to try to apply the contact lenses without eyedrops for at least five minutes. After that time, the parent may put only one drop in each eye per morning. If the child is not able to get the contact lens in the eye within five more minutes, he or she should wear spectacles that day. However, children are typically able to apply the contact lens on the first or second try following a drop of anesthetic. The child should be examined in one week to determine the progress and to monitor potential corneal changes. If the child is still not able to apply the contact lens, give him or her one more week. Tell the child that if he or she can't apply contact lenses after the second week, then contact lens wear is probably not an appropriate treatment alternative. Remember to retrieve the bottle of anesthetic after the therapy is complete.

Figure 6. While inserting a contact lens, hold the lids tightly and don't let the child squirm.

Successful Contact Lens Wearers

Knowing how to predict which children can successfully wear contact lenses can save you time and money, and it may save the child undue stress.

The person who faints when you touch the eyes is typically a young male, so you may believe that boys are less likely to adapt to contact lens wear. Although girls are typically more mature than boys of a similar age, girls and boys are equally successful at adapting to contact lens wear. However, the majority of contact lens wearers are female.

Although a child's ability to handle or care for RGP contact lenses does not depend on the child's age, younger patients may not be able to distinguish the initial discomfort of contact lens wear from absolute pain. They may not be able to understand that the sensation from the contact lens rubbing on the eyelids is temporary, so they may cry or refuse to allow contact lenses to be applied. At least you know the child's chance of successfully adapting to lens wear before purchasing contact lenses and attempting to teach application and removal.

We often think that the motivation to wear lenses must belong solely to the contact lens wearer. However, when young lens wearers are involved, parents must also be motivated. Once outside of your office, parents must encourage the child to apply his or her contact lenses every day and help with problems that may come up during the adaptation period. Parents must also be willing to allow the child to learn on his or her own and must tolerate the additional time necessary to apply or remove lenses.

In-office indicators of success include the child's ability to tolerate eyedrops and holding of the eyelids by the practitioner. Children who run to mommy for a hug between each eyedrop or are not able to answer your questions on their own are less likely to become successful rigid gas permeable lens wearers.

Unfortunately, no universal predictors of success exist. Children may become successful rigid gas permeable lens wearers despite initial signs that indicate the child may not be a good contact lens candidate. However, in one study, two-thirds of the children who could not adapt to rigid lens wear did not report to the one-week follow-up check. Most children who are not able to wear rigid lenses realize it in a relatively short period of time.

Figure 7. You and your young contact lens patients will have fun.

CONCLUSION

Myopic children represent a relatively untapped population of contact lens wearers that you can recruit into your practice. Their 80 percent success rate is higher than that reported for adults (69.6 percent). When examining children, be direct and honest. Children appreciate learning what to expect and a quick examination. Include the parents and the child in the examination to make them more comfortable and help you retain the patient. Above all, when examining a child, have fun and project this attitude to your patient.

Fitting a few child patients usually alleviates concerns that some doctors have about contact lens wear and care with young patients. It also demonstrates how much fun children can be to fit with contact lenses and follow through childhood (Figure 7). Because children talk at school and parents talk at activities the children participate in, you will find that fitting a few children can result in a large number of referrals and help you tap a relatively new population of contact lens wearers.

Jeffrey Walline, OD, MS, is a Senior Research Associate at the Ohio State University College of Optometry and the principal investigator of The Contact Lens and Myopia Progression (CLAMP) study.

References are available upon request. To receive references via fax, call (800) 239-4684 and request document #79. (Have a fax number ready.)

 

Extremely High Myopia ­ A Case Report

A highly myopic 12-year-old girl reported for a general eye examination with complaints of decreased vision over the past two months (Figure 3). A refraction revealed a spectacle prescription of ­38.25 ­0.75 x 015 in the right eye and ­37.25 ­1.00 x 055 in the left eye with a vertex distance of 8mm and the spectacles provided 20/70 visual acuity in each eye. The patient's eyelashes were sparse and bent from hitting the spectacle lenses, but she did not complain of discomfort upon blinking. We attempted to fit the patient with RGP contact lenses to provide optimal ocular health and the potential for myopia control, but all RGPs fell to the inferior limbus because of the extreme weight of the contact lens and the proptosis of the eyes.

The young girl was fitted with a pair of Alden Classic (Alden Optical) contact lenses with a power of ­30.00D in each eye. Visual acuities while wearing the contact lenses varied from 20/50 to 20/60. We darkened the contact lenses with a brown 3 tint, provided the same contact lens parameters for both eyes, and used a multi-purpose contact lens solution to improve the ease of caring for the contact lenses. We also recommended that she wear a pair of spectacles with a low prescription for safety purposes due to the high potential for a retinal detachment in and highly myopic eyes. The patient has successfully worn the contact lenses for over 18 months, and she has lost only one contact lens in that time.

 


Contact Lens Spectrum, Issue: February 2002