Some fundamental concepts about vision make it truly unique.
One such fundamental is that vision is a learned skill that develops over time.
Unlike hearing, which is fully developed at birth, vision is rudimentary. When
born, babies are routinely given an auditory evoked potential test, which is
effective at detecting hearing loss. Vision can be tested at this time, but a
visual evoked potential test cannot detect all vision problems.
The visual system undergoes profound developmental changes
in the first years of life—especially during infancy and toddlerhood.
Therefore, early diagnosis and treatment of visual problems can improve motor, cognitive and social development.1 Vision disorders are the fourth most common disability in the United States and the most prevalent handicapping condition in children.2 As many as 2% to 5% of preschool children—nearly four million children nationwide—are estimated to have impaired vision.3
A report by the National Eye Institute indicates that visual impairment in children is associated with developmental delays and the need for special educational, vocational and social services into adulthood.4 Of the 20 million children in America under age five, only 14% have had an eye exam. So, nearly 18 million children have not received an eye exam before entering school.5
Optometrists can take a proactive approach in addressing this alarming statistic. One of the newest avenues to provide infant examinations is the InfantSEE program. Managed by Optometry’s Charity—The AOA Foundation, InfantSEE is a program through which optometrists provide eye examinations for babies during their first year of life—a critical time when any findings may be treated proactively. The program is designed for babies between six and 12 months of age. Nine months is the ideal age to examine an infant. By nine months of age, the child is easy to examine, cooperates well, and also has undergone significant visual developmental milestones.
All children, and babies in particular, give you a finite amount of time to examine them before their attention shifts to something else. The problem is that you don’t know how much time you have! So, the key is to move through the examination efficiently. Also, try to obtain as much information as quickly as possible. So, here are some tips that may help when you find a very young patient in your exam chair.
Timing and Methods Matter
In general, it is a good idea to examine babies in the morning. In fact, it is a good idea to schedule your InfantSEE and senior patients in the morning—it makes for a great reception area combination. Parents should complete a history questionnaire prior to arrival, either online or through a document that they can mail back to you. The goal is to make the parents relaxed and focused on the baby, not the paperwork, when they arrive. And, make sure to minimize the waiting time for the baby. Before beginning the examination, review the case history to look for areas of concern. Upon entering the room, observe the infant’s general eye and facial structure, eye alignment, head position, and whether or not the baby makes eye contact. Babies love to look at lights and faces, and for the most part, they are not fearful.
The examination relies heavily on objective measurement. Test a baby’s eyes binocularly first, in order to minimize disruption of the binocular system. Babies find faces fascinating; finger puppets with cartoon characters or faces make especially attractive targets. Also, like most young patients, babies have a short attention span and love change. A target that can be illuminated will maintain interest if it was initially viewed un-illuminated and then illuminated. Use this target to evaluate pursuits, convergence near point, saccades and confrontation fields. Use a 10pd base-up prism in front of one eye to evaluate fixation status and infer interocular acuity differences. The Keystone Basic Binocular Test is one method to assess stereopsis. It uses anaglyphs and features targets that are appealing to infants.
Observe whether or not the baby reaches out for the target in front of the plane of the paper. The parent can assist by holding the anaglyphic glasses in front of the baby’s face while you present the target. Stereopsis tests that do not require polarized or anaglyphic glasses, such as the Synthetic Optics Stereo Tower and the Lang Stereo Test, are available, although they are typically best suited for slightly older children. The Hirschberg test provides a measure of ocular alignment in a few seconds. Dim the room lights (varying the lighting helps to control attention, too); the baby will look at the transilluminator, and you can observe ocular alignment while viewing the Purkinje reflexes. Quantify the amount of deviation by using the Krimsky method: Add prism until the reflexes appear to be aligned or by using the conversion factor 1mm = 22pd.
Also, perform a quick cover test while the baby views the transilluminator. Put your hand (the one not holding the transilluminator) above the baby’s head and use your thumb as the occluder. The Brückner test is fast and easy to perform, and it provides a great deal of information. It can detect amblyopia, strabismus, anisocoria, anisometropia, ammetropia, media opacities and more. Perform this test at 80cm to 100cm in a dimly lit room. Shine an ophthalmoscope light over the baby’s face so that both eyes are illuminated simultaneously, and start with a high plus lens in the ophthalmoscope. Decrease the plus until the red reflexes are visualized clearly. Compare the color, brightness and symmetry of the reflexes. The eye that is strabismic will appear brighter as you are viewing a non-macular portion of the retina—it has less macular pigment and therefore reflects more light. Likewise, the eye with the larger pupil (anisocoria) or higher refractive status will appear brighter. An easy mnemonic device for such examinations is “brighter is bad.” This test takes just a moment, but provides a great deal of information.
The preferred method for infant retinoscopy is the Mohindra method, which is performed monocularly in the dark while the baby is viewing the retinoscope. For babies, subtract 0.75D from your gross finding, and for children more than two years of age, subtract 1.25D from your retinoscopy finding—this is the type of non-cycloplegic retinoscopy that most closely correlates with cycloplegic retinoscopy. Use your hand to occlude one eye while holding the trial lens in front of the baby’s fellow eye.
| How Long Does an Infant Exam Take?
Infant exams take less time than adult exams. After all, your testing is objective; you don’t ask the baby, “Which is better, one or two?” In fact, infant exams are far easier and faster than examining a two-year-old. Once you review the completed paperwork and start your examination, it takes no more than 15 to 20 minutes until the instillation of the drops. After you instill the drops, the parent and baby wait in the reception area until the drops take effect. When you bring the baby back in, you will spend another five to 10 minutes performing a wet retinoscopy and indirect ophthalmoscopy. Reviewing the findings with the parent takes another few minutes. That’s it! The parent and child leave, very grateful for your care and concern. To insure that the examination flows smoothly, be sure that the parent has completed the history forms and paperwork and that you have reviewed them prior to starting the exam. Schedule InfantSEE patients in the morning. Depending on your office schedule, you may want to schedule InfantSEE appointments for between 15 and 30 minutes. |
Acuity Measurement
Now you are finally ready to assess acuity. This is best accomplished by taking advantage of babies’ tendency to look at complex patterns. A forced preferential looking technique is best; the baby is presented with two targets simultaneously, one blank and the other with a square wave grating (stripes). Present the plates with the patterns facing the baby, without your knowing which of the two has the pattern, while you view the baby from behind the test plate. After noting which direction the baby fixated, see if the baby chose to view the pattern. Keep proceeding with finer and finer targets until the baby stops responding, and keep in mind that sometimes the baby stops responding because he or she is bored. In such cases, present the test plate vertically to create variety and re-engage the baby’s interest.
Remember that this acuity measurement does not represent the infant’s maximum acuity; it merely measures what he or she responded to that day. It does, however, become the baseline for future testing. Next time, you don’t have to start with the largest stripes. Instead, you can hone in and move forward. Base your acuity measurement on your testing distance and the space between the stripes. This test is challenging for the baby, so it is usually performed near the end of the exam, before instilling dilating drops. Babies fatigue easily with this test, so it is often performed binocularly at the first visit. If you’re concerned about one eye, then test it at the follow-up visit first.
Ocular Health
You can use a variety of tests to evaluate ocular health. Examine the visible corneal diameter to rule out congenital glaucoma and evaluate the lid margins and anterior segment using either a 20.00D lens and transilluminator, head-mounted loupe with its own illumination source, a Bluminator (a handheld magnifying lens surrounded by its own white or cobalt blue light source, by Eidolon), or a handheld slit lamp. Dilation and cycloplegia are recommended in order to obtain the most thorough view of the retina and refractive status. Cyclomydril (0.2% cyclopentolate/1% phenylephrine, Alcon) is the diagnostic agent of choice; it is a combination drop specifically designed for infants.
Or, another alternative is 0.5% tropicamide. The easiest way to instill the agent is to have the parent hold the baby prone in his or her lap and instill one drop into each eye. Instill the first drop in the eye closer to the parent’s chest—when you do, the baby will reflexively turn his or her head in towards the parent, and it is then easier to instill the drop in the eye closer to you. If you move quickly, you can instill both drops without much difficulty. The baby will blink, and the drop will roll in on its own. Cyclomydril does not seem to sting babies’ eyes, though they may be startled. Ask the parent to take the baby out of the exam room while you wait for the baby’s eyes to dilate. Then, repeat retinoscopy and perform ophthalmoscopy utilizing a binocular indirect ophthalmoscope or monocular indirect ophthalmoscope.
| How to Sign Up For InfantSEE
The national public health program InfantSEE was created by the American Optometric Association and Johnson & Johnson’s The Vision Care Institute LLC, in response to a challenge by former U.S. President Jimmy Carter. Two of President Carter’s grandchildren had amblyopia that went undetected until they were in school. He asserted that if he, a former President of the United States, educated and with access to the best care, did not know about the importance of early comprehensive eye examinations in children, then neither did most others! In 2002, he challenged the AOA to do something about this problem. By June 2005, InfantSEE was born. This is AOA member optometrists’ gift: an optometric examination for every baby in this country during their first years of life. Examining infants is fun, easy and rewarding. Since InfantSEE began, nearly 8,000 optometrists have enrolled in this public health program. The program not only changes babies’ lives, but it has actually saved lives too! AOA members have the opportunity to educate their patients about the importance of a lifetime of vision care, and that care can begin as early as six months of age. AOA membership is a pre-requisite for providing care. If you are a current AOA member, please visit www.infantsee.org/enroll.xml to sign up. If you are not a member, but would like to become one, please contact your state optometric association to initiate the process. All new providers receive a welcome packet that includes: • Welcome letter from the AOA president. • Letter of agreement for participation in InfantSEE. • InfantSEE Trademark Licensing agreement. • Supply of promotional materials. • Instructional CD on how to perform an InfantSEE assessment. • Staff FAQs. • Chairside guide. • Supply of clinical assessment forms, patient history forms and return address labels. |
Developmental Tracking
That’s all there is to it! You have assessed all of the essential areas: history, binocularity, refractive status, ocular health and acuity. Now, you need to determine if the baby is on the developmental superhighway or is “off track.” If the baby presents with risk factors outside the norm, careful monitoring is essential. For refractive concerns, remember the 3x3 rule—the baby returns for three progress checks three months apart. It is important to leave room for emmetropization, Mother Nature’s way of helping most children develop normal vision. After three visits, however, if the infant is still outside the refractive norm, prescribing corrective lenses is indicated. Performing infant eye examinations allows for ample time to monitor emmetropization and determine if you need to intervene. While new research indicates that neuroplasticity continues throughout life, early intervention facilitates good visual development, which can have a profound impact on motor, social and cognitive development.6 To maximize development of stereopsis, the earlier the visual cortex is stimulated through corresponding retinal points, the better.7 By examining the baby before age one, you can intervene when binocularity is abnormal and provide the opportunity to develop good stereopsis and prevent amblyopia. What a wonderful opportunity we have! Optometrists can help a child develop the best visual capabilities possible.8 I hope that you will consider joining me and the other 8,000 AOA members enrolled as InfantSEE providers. These infants need your help, and you can make a real difference in their lives!
Dr. Thau, a Fellow of the American Academy of Optometry and a Fellow of the College of Optometrists in Vision Development, is an associate clinical professor at the SUNY State College of Optometry and a trustee of the American Optometric Association. She has been an InfantSEE provider since the program’s inception in 2005.
1. Duckman RH. Visual Development, Diagnosis, and Treatment of the Pediatric Patient. Philadelphia: Lippincott Williams & Wilkins, 2006:3.
2. Ciner EB, Dobson V, Schmidt PP, et al. A Survey of vision screening policy of preschool children in the United States. Surv Ophthalmol 1999 Mar-Apr;43(5):455-57.
3. American Academy of Pediatrics. Maternal and Child Health Improvements Project: Project Summary. 2001 Aug.
4. Report of the Task Force on Vision Impairment and Its Rehabilitation. Washington, DC: National Eye Institute, 1998.
5. Vision Council of America. Practice strategies: back to school. Optometry 2000 Aug;71(8).
6. Ge S, Yang CH, Hsu KS, et al. A critical period for enhanced synaptic plasticity in newly generated neurons of the adult brain. Neuron 2007 May;54(4):559-66.
7. Duckman RH. Visual development, diagnosis and treatment of the pediatric patient. Phialdelphia: Lippincott Williams & Wilkins 2006:135-137.
8. AOA Clinical Practice Guidelines on Pediatric Eye and Vision Examination. 2nd ed.Available at: http://aoa.org/x4816.xml (Accessed September 2009).
