Special tools, techniques make refracting pediatric patients easier
The American Optometric Association (AOA) recommends that all children have their first eye exam at 6 months of age. The purpose of this exam is to inspect the child's ocular health and to detect refractive errors and conditions, such as amblyopia.
In this first exam, doctors should make sure the child has good alignment and no external pathology, such as ptosis. Doctors also should examine the structures of the eye, including the optic nerve and lens, and look for congenital cataracts.
"If you find an abnormality, you certainly want to address it, and the sooner you address it the better. That's the whole point of doing the exam at an early age," said Michael Bartiss, OD, MD, FAAO, pediatric ophthalmologist at Carolina Eye Associates.
An effective test for visual acuity in infants is preferential looking cards, said Kelly A. Frantz, OD, FAAO, an associate professor at the Illinois College of Optometry. These are a series of cards that are gray on one side and have black and white stripes on the other. Psychological research indicates that infants prefer to look at a pattern rather than the bland gray, according to Dr. Frantz. As long as the infants can see the stripes, they usually will turn their heads to look at them. As with adults reading lines of decreasing size on a chart, the infants are presented with cards containing stripes that are closer together until they stop looking, she said.
The child's eyes should be dilated and checked again for abnormalities, then the optometrist should complete an objective cycloplegic refraction with a retinoscope, said Bruce D. Moore, OD, The Marcus Professor of Pediatric Studies at the New England College of Optometry. This refraction should always be conducted while the patient is cyclopleged to ensure the accuracy of the examination, he said.
Cycloplegia helps provide a more definitive baseline measurement of the refractive error, while a child who is not cyclopleged might be able to overcome even high hyperopia by using active accommodation, he added.
Choosing the agent
---Skiascopy bars: These plastic holders contain a series of lenses in order of increasing power and are used to perform retinoscopy.
Dr. Moore uses 1% cyclopentolate drops as a cycloplegic agent. Dr. Frantz also has had success with a cycloplegic spray made up of cyclopentolate, tropicamide and phenylephrine. Rather than applying drops to the patient's eye, the cycloplegic agent is sprayed on the child's closed eyelids at the base of the eyelashes. When the eye is opened, enough of the spray drains into the eye to be effective, but it does not sting as much as drops, she said.
Dr. Bartiss uses 1% atropine in toddlers and older children for cases where complete cycloplegia is difficult to obtain at the time of the initial visit. Parents apply the drops the morning and evening before the exam and then again the morning of the exam. Atropine is a stronger, longer-lasting agent that achieves better results in patients with very dark irises, he said. Optometrists must warn parents to wipe away excess drops to avoid systemic absorption, which can cause belladonna poisoning.
The characteristics of this include the child being, "Dry as a bone, red as a beet, hot as Hades and mad as a hatter," Dr. Bartiss said. If these side effects occur, the parents should take the child to an emergency room and bring the bottle of drops or tube of ointment so the doctor will know how to treat the child.
For the retinoscopic exam, Dr. Frantz uses skiascopy bars, which are plastic holders that contain a series of lenses in order of increasing power. These are used to perform retinoscopy instead of the phoropter. Hand-held trial lenses also can be used, but the lens bars eliminate the need to pull out each new lens individually, she said. These extra steps could cause the child to lose interest and become uncooperative.
When to follow up
Doctors should take note of hyperopia of more than 2 D and astigmatism of more than 2 D, said Julie B. Ryan, OD, MS, an associate professor at the Southern California College of Optometry. Astigmatism is relatively common in infants and is often a transient finding, she said. The condition should be followed, but research indicates that astigmatism does not have an impact on the visual system until the child approaches 1 year of age, Dr. Ryan added.
Patients with more than 3 D of myopia should be followed, though these myopes will not necessarily develop secondary problems such as strabismus or amblyopia, Dr. Ryan said. Once children reach 9 months of age, they will need a full correction because they are beginning to walk and look at things more closely, she said. If the proper accommodative to convergence ratio does not develop because the myopia is left uncorrected, a secondary binocular disorder such as exotropia can occur when correction is given later.
In preschoolers with anisometropia, Dr. Frantz recommended waiting to prescribe because this condition can disappear in the first 3 or 4 years of life. If anisometropia of greater than 1 D is stable and is interfering with binocularity or acuity development, a correction must be given. Sometimes, a partial correction for the refractive error is prescribed because it will interfere with possible emmetropization, she said.
In children who display significant hyperopia, anisometropia or astigmatism, Dr. Ryan schedules a follow-up 3 months after the first exam. A rule suggested by Elise Ciner, OD, is to conduct three follow-up examinations at 3-month intervals, Dr. Ryan said. This will enable the optometrist to track the child's condition to determine whether it is improving or if it will require treatment to avoid the development of a secondary condition, she said.
Age at first exam
Dr. Moore disagrees with the timing of the first exam at 6 months of age. The visual system is dramatically changing both structurally and functionally at that age; this early test will be of little use, he said. "The process of emmetropization goes on over the first 3 years of life, so a refractive error that's present at 6 months of age is not necessarily going to be present at 3 years of age when it really starts to count," Dr. Moore said.
Conditions that an optometrist would treat at 6 months of age, such as severe strabismus, hyperopia of 10 D or myopia of 10 D, would be easily noticeable to a parent or pediatrician, he said. Certainly, if there is an indication of a problem or a child is in a high-risk category, an examination is indicated.
At 3 years of age, the child's ocular structures and vision will be more fully developed and stable, allowing the doctor to reach a more definitive refraction, Dr. Moore said. At this age the child also will be able to participate in more tests, allowing the doctor to gather more accurate information, he added.
Significant alignment problems can begin to manifest in children by 6 months of age, and an effective screening method for the factors that can lead to amblyopia is the Vision Photoscreener from Medical Technical Innovations Corp., Dr. Bartiss said. The photoscreener is similar to an instant camera and uses high-speed film to take an instant picture of the child. Reviewing the characteristics of the reflection through the pupil, the doctor can detect media opacities, such as a corneal scar or a congenital cataract, which will create a blotch in the reflection, he said.
Doctors also can look at the symmetry of the corneal reflexes to determine if there are problems with eye alignment as well as external features of the eyes and adnexa, he added.
The sensitivity, specificity and positive predictive value, along with the negative predictive value are extremely high, Dr. Bartiss said, "much better than any other screening device we have." In older children who are able to give subjective responses, it may not be necessary to use this device, but in pre-verbal children and children with disabilities, it is a very effective tool, he added.
When, how to treat infants
When amblyopia is detected, one form of treatment is patching the eye that has better vision. In infants, this should not be done for more than a few hours a day to avoid occlusion amblyopia, where the vision in the eye behind the patch deteriorates, Dr. Frantz said. Initially, young children may resist wearing the patch, but an effective way to prevent them from removing the patch is by using water wings, which keep children from bending their elbows, Dr. Bartiss added.
Although accommodative esotropia usually develops at age 2 or 3, doctors should be aware that it sometimes can be detected in children during their first exam at 6 months, Dr. Bartiss said. Strabismus, especially esotropia, should be treated immediately.
"One of the most commonly held myths is that if a child has esotropia at an early age it's likely to disappear as he or she gets older. If the child has esotropia, that's not likely to be the case, so I think those issues need to be addressed," he added.
Research has shown that proper stimulation to each eye, and both eyes simultaneously for binocular vision, is necessary for proper cellular development of the visual pathway at the lateral geniculate nuclei and visual cortex, Dr. Bartiss said.
Some doctors often are not aggressive enough in correcting hyperopia, particularly in cases of esotropia, because they may assume the hyperopia might not be significant in the alignment problem, Dr. Ryan said. She believes that almost any amount of hyperopia can affect alignment problems and should be corrected.
In children with accommodative esotropia and significant hyperopia, Dr. Bartiss recommends glasses, even in 6-month-old children. Finding suitable frames can be a challenge, so he recommends glasses with a small eye size to minimize the weight and adjustable nose pads, because children this age generally have not developed much of a bridge.
Contact lenses for hyperopia?
In children with hyperopia of greater than 6 D, or if there is anisometropia with a difference of 4 D or more, Dr. Ryan believes contact lenses should be used. In cases of anisometropia, for example, contact lenses eliminate possible diplopia created by the different refractive corrections before the right and left eyes, she said.
Dr. Bartiss prefers spectacles to contact lenses because of the increased risk of infection created in young children who frequently rub their eyes. Parents often have difficulty placing lenses in and taking them out of infants' eyes. Each case must be considered individually, he added.
In children between 2 and 2½ years of age who have accommodative esotropia, Dr. Ryan commonly uses straight-line bifocals. This corrects the secondary esotropia caused by the accommodative effort of the child to see at near point. Some parents might prefer progressive addition lenses for cosmetic reasons, but bifocals guarantee that the child has the proper power in front of the eyes, she said. The progressive lenses vary in power, and this variance could reduce the effectiveness of the treatment if the child does not look through the bifocal part of the lens, Dr. Ryan said.
Dr. Bartiss typically prefers FT-28 or FT-35 segments set at mid-pupil.
Dr. Frantz also uses straight-line bifocals to treat accommodative esotropia, but said that she prefers to wait until children are 3 or 4 years old. Young children often cannot learn how to look through the bifocal segment when they have to look at close items, so the bifocals are not effective, she said. To ensure children look through the bifocal, this segment is placed higher in children's lenses than in adults', with the line of the bifocal going right through the pupil.
In cases of alignment problems, doctors should think foremost about the more severe possible causes, such as brain tumors or bleeding in the brain, Dr. Moore said. "If you have a child with a sudden onset of strabismus, I think it's a brain tumor until proven otherwise," he said.
In children who do not show significant refractive error or alignment problems, the AOA recommends a follow-up examination between 2½ and 3 years of age.
At the age of 3, children can participate, enabling optometrists to do a more complete examination, Dr. Bartiss said. Visual acuity can be determined using Lea picture charts and such techniques as the Tumbling E Test. Binocular vision can be tested using the Worth four-dot method, and stereopsis can be tested using the Stereo Fly or Random Dot E tests (Titmus Optical Inc.). Other functions the doctor should test are motility by looking at eye movement behavior and color vision.
In this exam, children still cannot be relied on for a good subjective refraction, so the doctor should continue to depend on an objective refraction, Dr. Frantz said.
Dr. Frantz will take the results of the objective refraction with the retinoscope to reach a preliminary prescription, then put those tentative lenses in a trial frame and have the child reread part of the eye chart. "I decide if it's better with the lenses or not based on how well they did with the visual acuity test, and I might even modify the lenses slightly and try the visual acuity again," she said.
One area where children can take part in the subjective refraction is in cases of astigmatism of 2 D or more, Dr. Frantz said. With children of 4 or 5 years of age, she will use the retinoscope to find the power and axis of the astigmatism, then refine those findings subjectively.
"You can rotate the lens to different axes in the trial frame and have the child stop you when things look their very best. Some children can do that if they have a lot of astigmatism because vision gets very poor if you rotate to the wrong axis," she said.
Gaining the child's cooperation
One of the biggest challenges in working with pediatric patients is getting them to cooperate in the exam. This process begins by having a waiting area that is child-friendly, Dr. Bartiss said. "I think you need to play, you need to establish a rapport. That can be as simple as making sure you have an environment where kids can feel relaxed," he said.
Dr. Bartiss and his staff wear "civilian clothes" instead of lab coats to avoid the "white-coat syndrome," which often frightens children.
Using videotapes is an effective way to keep the child's attention during the retinoscopy and ophthalmoscopy, Dr. Frantz said. Other techniques such as using automated toys or having a parent or sibling stand across the room to entertain the child work as well, she added. Doctors should work quickly and keep the child's attention by talking during the exam.
Where there is a specific problem or disease, the optometrist must do his or her best to obtain the clinical information needed even if the child is not cooperative. In routine examinations, however, it is often better to reschedule, Dr. Bartiss said.
"Don't force the child. If it's naptime or they're crabby, reschedule. If you try to force it, it's going to be a miserable experience, and you'll have a very difficult time the next time the child comes in," he said.
Because the doctor cannot rely entirely on the child's responses, it is important to listen to the parent's concerns. "If a parent comes in and tells you there's something wrong, there's something wrong until proven otherwise. In other words, listen to the parents. Don't discount somebody as being a nervous mother or father," Dr. Moore said.
A complete history for the child, including overall health and ocular development histories, is very important, Dr. Bartiss said. "A number of conditions have other systemic findings that go along with eye problems -hearing problems, for example," he said.
The doctor also should collect a thorough family health and eye history. Frequently, parents will not mention a significant part of the child or family history because the doctor did not ask, he said. "Don't assume the parents know what information you need," he added.
For Your Information:
- Michael Bartiss, OD, MD, FAAO, is a pediatric ophthalmologist at Carolina Eye Associates and a member of the Primary Care Optometry News Editorial Advisory Board. Dr. Bartiss can be reached at 2170 Midland Rd., Southern Pines, NC 28387-2927; (910) 295-2100; fax: (910) 295-8368. Dr. Bartiss has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
- Kelly A. Frantz, OD, FAAO, is an associate professor at Illinois College of Optometry and works in the pediatric/binocular clinic at the school. Dr. Frantz can be reached at Illinois College of Optometry, 3241 S. Michigan Ave., Chicago, IL 60616; (312) 949-7281; fax:(312) 949-7653. Dr. Frantz has no direct financial interest in the products mentioned in this article, nor is she a paid consultant for any companies mentioned.
- Bruce D. Moore, OD, is the Marcus Professor of Pediatric Studies at the New England College of Optometry and can be reached at 424 Beacon St., Boston, MA 02215; (617) 266-2030; fax:(617) 236-6323. Dr. Moore has no direct financial interest in the products mentioned in this article, nor is he a paid consultant for any companies mentioned.
- Julie B. Ryan, OD, MS, is an associate professor at the Southern California College of Optometry and is in private practice in Irvine, Calif. She can be reached at the Irvine Optometric Group, 4950 Barranca Pkwy., Ste. 310, Irvine, CA 92604; (949) 559-5905; fax: (949) 559-8984. Dr. Ryan has no direct financial interest in the products mentioned in this article, nor is she a paid consultant for any companies mentioned.