Alex Christoff is assistant professor of ophthalmology at The Wilmer Eye Institute at Johns Hopkins Hospital in Baltimore. E-mail him at email@example.com.
The common eye problems found in adults, developing over decades of life as acquired disease, are different in children. There is an old pediatrics adage that “children are not little adults.” This is certainly true when it comes to the pediatric eye exam that many allied health care personnel find themselves facing, often with dread, on a weekly or daily basis.
The common eye problems found in adults, developing over decades of life as acquired disease, are different in children. There is an old pediatrics adage that “children are not little adults.” This is certainly true when it comes to the pediatric eye exam that many allied health care personnel find themselves facing, often with dread, on a weekly or daily basis.
Obtaining pertinent history-often from a source other than the patient-and relevant clinical information to help the physician arrive at the proper diagnosis and provide the appropriate treatment, requires a different and creative approach, patience, and talent. Technical staff who themselves are parents have a distinct advantage: they are familiar with the nuances of behavior in young children. They know the various developmental milestones, when children start to sit up, stand, learn to walk, and start talking. These milestones are an important part of the pediatric history and often play an equally important role in illuminating and the underlying cause of clinical signs and symptoms.
The pediatric eye exam can be broken down into five basic components:
Preliminaries of an exam
The pediatric eye screening begins by observing the child at ease, first in the waiting area as you walk out to call and greet him, then as he walks in to the exam room with you. Introduce yourself. Offer a handshake to adults and older children. Be cognizant of the fact that some cultures and religions do not shake hands.
You should become familiar with your patient demographic and apply these concepts accordingly. Comment to a child about clothes, toys, what they’re eating, siblings, etc.
As you enter the exam room, have the children and their families take seats away from the exam chair if possible, guarding exam-chair time as a precious commodity. Once the child is seated in the exam chair, her attention timer is ticking.
If you approach the interview and this initial part of the exam with dread, children will sense your tension and become uncomfortable. It is incumbent on you as the examiner to gain the child’s confidence and trust, and you will want to do so in a relaxed, open, honest, and playfully engaging way.
Once the child is seated in the exam chair, you should establish and maintain eye contact. Sit at the child’s eye level by lowering your chair/ exam stool and/or raising the child’s exam chair. Maintaining eye contact may or may not be possible with autistic children who often avoid eye contact with others.
You will want to initiate verbal rapport with simple questions comments, such as, “How old are you?” Over-estimate age and grade level. Ask about siblings who came with her to the appointment today. These quick simple pearls warm the experience for the child and her family, and for you as the examiner.
It is important to remember that as you work with children you have to focus your exam. Check what you need early on while you have cooperation, and save the more difficult tasks for last. You will have to develop a different vocabulary.
For example, say “magic sunglasses’ when introducing the anaglyphic glasses of the Worth four-dot test and the polarized glasses of the various stereo acuity tests. Use “special flashlight’ to describe your retinoscope, and “funny hat” or “coal miner’s hat” when describing what the physician will do with the indirect ophthalmoscope. “Magnifying glass” is an apt description of the magnifying lens used with the indirect ophthalmoscope, and suggest “let’s ride the motorcycle/bicycle” when it is necessary to do a slit lamp exam.
“When all else fails, take a history.” These words were the sage advice of J. Lawton Smith, MD. Former ophthalmology resident at the Wilmer Eye Institute in the 1950s, Dr. Smith went on to become an internationally recognized neuro-ophthalmologist at the Bascom Palmer Eye Institute in Miami.
All medical histories should begin by identifying the patient’s chief complaint, preferably in as close to their own words as the electronic medical records of the present day may allow. Examples of a chief complaint include, “decreased vision,” “headaches,” “blurred vision,” or “double vision.”
The clinician will next want to evaluate the history of present illness, or HPI. For the parents, ask who referred the child in to your office and why. Sometimes the simple question, “What can we do for you today?” works best. Try to establish when the problem started (onset), how often the problem is noticeable (frequency/severity) and when the symptoms manifest do themselves, how long do they last (duration).
Who notices? Relatives, teachers, the pediatrician? Sometimes you can ask the child simple question like, “Which eye hurts?” or “Which is the bad eye?” But avoid complex topics like questions about double vision in younger children because this is a difficult concept at best for most preschoolers.
Expand your history with questions about treatment and what has been done to address the problem.
Was a more extensive workup required that might have included bloodwork or imaging studies? And how has the problem developed or changed in the interim between the last office visit and the most recent visit? Do the parents know anything about the problem? This is the Internet age, and most parents have explored their child’s eye problem online before having sought treatment.
With the HPI, you are trying to develop a differential diagnosis – basically, a short list of possible causes by defining the problem and making sense of the history. Of course you will want to explore the symptoms and signs observed by the parents. Are they constant, or intermittent? When do they occur? What time of day? Are they worse at the end of day, or with fatigue?
Children often present to the pediatric eyecare practitioner because they failed a vision screening at school or at their pediatrician’s office. It is very important for the technician to ask when the child was tested. There are obvious clinical implications and expectations if the failed screening was 6 months ago vs. a few weeks ago.
What was wrong? What part of the screening test did they fail? Was it because of an observed misalignment? Did they do poorly on the visual acuity test? How was vision measured? Was it an age-appropriate test? Did the screener use letters, numbers, pictures, and isolated, linear, or single-surround optotypes?
As you will learn in the pages that follow, all of these elements factor in to how young children perform on visual acuity tests. In other words, a failed vision screening may or may not really be indicative of a real problem.
When it comes to strabismus, parents will often use the term “lazy eye” to mean strabismus and/or amblyopia, the decreased best-corrected visual acuity often associated with strabismus. Similarly, many parents use the word “crossing” to refer to any type of strabismus; esotropia, exotropia, even in describing vertical deviations. All of which means the technician will have to verify the direction of the observed misalignment graphically with the parents in order to make sense of the history.
I use my hands to physically simulate esotropia, or in-crossing of the eyes by pointing to my nose with both hands. Similarly with a suspected exodeviation, I use both hands to point out away from my ears to simulate an outward drifting of the eyes (Figures 1 and 2).
Explore possible strabismus more in your history by asking which eye is seen to be misaligned. Do the parents notice any squinting? Bilateral squinting is typically a sign of uncorrected refractive error or ocular allergy, while unilateral squinting is often associated with strabismus.
Ask about eye rubbing. Does the child always rub the same eye? Who notices? Is it the parents, the pediatrician, the child’s teachers, other family members? Is eye misalignment visible in family photos? Is it constant, intermittent? Is it happening at distance fixation, with daydreaming, or at near fixation, when the child attempts to focus?
Double vision occurs when one fovea is not directed at the same object of regard as the other. While this is quite common in older patients with an acquired strabismus, it is uncommon in young children with an early-onset misalignment who develop suppression, or the ability to “turn off” the image from the deviating eye.
This phenomenon occurs at the level of the brain’s cerebral cortex. So double vision in a pediatric patient, if it is real, implies an acquired etiology and may require special laboratory tests or neuro-imaging studies like MRI or a CT scan to explore a possible neurological cause.
When interviewing patients of any age with a complaint of double vision, one of the first questions the clinician should ask: “Does the double vision go away if you cover either eye?”
Binocular diplopia resolves with unilateral occlusion, while monocular diplopia, diplopia still present after covering one eye and most often due to refractive error, resolves in almost all cases with a pinhole. You should also ask the patient if the double vision is worse in certain positions of gaze, at a certain time of day, or at rest.
Children who were born prematurely have been shown to have a substantially higher incidence of strabismus, amblyopia, and high refractive errors compared to full term controls.4 So for these reasons, you will want to ask questions about the pregnancy, birth, and developmental history of all pediatric patients.
For the pregnancy, you should ask the mother or parents about illicit drug use, consumption of alcoholic beverages, whether there was a problem with preterm labor, maternal age, paternal age, prematurity (a full-term delivery is 40 weeks), low birth weight, use of supplemental oxygen, presence of retinopathy of prematurity and whether it regressed/resolved on its own or if it required laser photo-ablation, whether it was a normal spontaneous vaginal delivery (NSVD) or caesarean section, and whether this was planned or unplanned, and whether there were any labor complication.
Continue with questions about birth complications, whether there was an anoxic event/loss of oxygen/delayed breathing, or any breathing problems. You should inquire as to whether there was any trauma/instruments used during the delivery (forceps, suction), or any history of intra-cranial hemorrhage, convulsions, seizures, or known syndromes.
Technicians who are parents have a decided advantage here because they are familiar with the developmental milestones of their own children. But there are a few developmental milestones that all technicians can easily learn to help shed light on the observed ophthalmic eye findings as they may contribute to a final diagnosis.
You should ask if the child has met all of his or her milestones to date. Familiarize yourself with some of the basic components of pediatric developmental milestones, available online at the website of the American Academy of Pediatrics.5
Most children are very healthy and take few, if any, medications. However, this may not be the case for children seen in a tertiary care facility or a hospital that is part of a large inner city medical training center. Conditions associated with prematurity like retinopathy of prematurity, hydrocephalus, seizure disorders, anomalous birth defects and syndromes, and other health problems become more common in these situations.
If you are employed in one of these facilities, you need to come to terms with the various ophthalmic sequelae and the medications associated with them so you know what to ask if and when these children present to your clinic. Because these kids tend to have a team of healthcare providers, the past medical histories and medications are often, but not always, well documented in the medical record.
Asking about the family history for pediatric patients is not only good medicine, it is now mandated by the federal government as part of its Meaningful Use criteria for affective utilization of the information obtained by ophthalmologists in the electronic medical record, or EMR. Questions about other individuals with strabismus, nystagmus, amblyopia, or history of early-childhood patching or glasses should be routine. Additionally, individuals with childhood blindness, glaucoma, cataract, or heritable diseases should be documented in the EMR.
Lastly, it is also important to know the living conditions at home because social stressors like divorce, abuse, foster parents, and institutionalization due to developmental delay may have implications for compliance with prescribed glasses, patching, use of eye drops, and attendance at follow-up examinations.
Ask about who lives with the child, especially if he is accompanied by only one parent, grandparent, older sibling, aunt, or uncle. Is there smoking in the house? Are the parents married, separated, or divorced? Are there pets in or around the house?
The sensorimotor examination is the key element in the pediatric eye screening. The problems that bring children in to see the pediatric eyecare professional include a number of different types of strabismus, vergence abnormalities, amblyopia, and refractive dilemmas, all of which can impact ocular alignment, depth perception, and sensory fusion. The examination typically starts by assessing (sensory) fusion first and then measuring (motor) alignment by prism and alternate cover testing, both typically performed by a trained specialist.
Assessing sensory fusion begins by measuring gross binocular fusion potential with the Worth 4-Dot Test, which uses red/green anaglyph glasses and a special flashlight that displays four lights-two green, one red, one white. Convention dictates that the patients wear the glasses with the red lens over the right eye, if there is a choice. The flashlight is then shown to the patient at both distance and near fixation, and she is asked to report how many lights are seen with both eyes open.
The response for binocular fusion is four lights seen, in any color arrangement. The response for suppression is only one color seen, either only two lights (red) for suppression of the left eye or only three lights (green) for suppression of the right eye. A response of five lights seen is consistent with diplopia or manifest strabismus.
Interpreting the results of the Worth 4-Dot test should be done with caution because the test is dissociating, meaning it may cause an otherwise controlled or intermittent strabismus or phoria to manifest itself as a tropic deviation behind the darkened anaglyph glasses. Children from age 3 to less than 5 years of age can be asked to just count the lights on the flashlight by touching them one at a time, usually just at near fixation (Figure 3).
Near stereo acuity testing assess fine sensory fusion ability, requiring clear and equal acuity in both eyes and finer motor alignment than what is required by the Worth 4-Dot test. There are a number of near stereo tests available, though the industry standards are typically the Titmus or Randot stereo tests from Stereo Optical.
In each test, the wings of the fly are the most disparate and easily perceived, even by children as young as 2.5 or 3 years of age. The circles of the test correspond to increasingly fine stereo images-the more circles that are seen, the finer the stereo acuity, and the better the visual acuity in each eye. We use the animal figures only for preschool children. Many of these tests come in pediatric versions as well, which can enhance cooperation.
In assessing strabismus, there are basically two ways to quantify ocular misalignment. The prism and alternate cover test utilizes either bar and/or loose prisms and some type of opaque occluder. Often a child will not allow you to approach him with an occluder, so your hand, palm, or thumb, though not preferable, will have to do (Figure 4).
Corneal light reflex estimating techniques are based on the observed position of a corneal light reflex in relation to the patient’s pupil in the misaligned eye. These will be discussed below. But let’s first talk about the basic type of strabismus seen in the pediatric clinic.
When strabismus does present itself, there are four types of deviations with which the clinician needs to become familiar. An esotropia is an eye that deviates in toward the nose, with a corneal light reflex temporal to the center of the pupil. An exotropia is an eye that deviates out away from the nose, with a corneal light reflex nasal to the center of the pupil.
A hypertropia is an eye that deviates up with a corneal light reflex inferior to the center of the pupil. And a hypotropia is an eye that deviates down with a corneal light reflex superior to the center of the pupil. The term orthophoria or orthotropia means that the eyes appear straight with corneal light reflexes centered in both pupils or by alternate prism and cover testing.
Clinicians who routinely perform sensorimotor evaluations on younger children have to find creative ways to maintain the child’s interest. For distance measurements, animated toys and projected movies work well. A parent or coworker can also assist by standing at the end of the exam lane, holding a flashing toy, and calling the child’s name.
For near measurements, young children are asked to sit on a family member’s lap. The child usually feels more secure there, and the family member can then be asked to hold a fixation stick or toy on the examiner’s nose, leaving both hands free to hold an occluder or prism bar.
Unfortunately, it is not the scope of this article to discuss the specific details of how to perform the prism and cover test. The take-home message is that children tend to respond favorably to animal puppets and toys, and of interest, there seems to be some science to support why.6
Despite our best efforts to engage the patient, there will times when a frightened or uncooperative child will not permit sensory testing or a prism and alternate cover test. Other times, a patient may have such poor vision in one eye, that she is unable to fixate well enough to be measured with prism and alternate cover testing. In these circumstances, the clinician can use a number of corneal light reflex tests to estimate and quantify the observed strabismus.
To perform the Hirschberg test, simply shine a bright penlight or fixation light at the patient from a distance of about arm’s length. Observe the position of the corneal light reflexes from the flashlight in each eye of the patient. They should be centered in each pupil if the eyes are straight.
However, if the light reflex is displaced near the pupil margin in one eye, this represents an approximate deviation of 15 degrees or 30.00 prism diopters (PD). If the light reflex in one eye is displaced mid-iris, this represents 30 degrees or 60.00 PD of misalignment.
And if the corneal light reflex in one eye is displaced at the limbus, this represents approximately 45 degrees or 90.00 PD of misalignment. It is up to the examiner to identify the proper type of strabismus or direction of misalignment, but temporally displaced corneal light reflexes correspond to esodeviations, medially displaced light reflexes to exodeviations, inferiorly displaced light reflexes to hyperdeviations, and superiorly displaced reflexes to hypodeviations.
To estimate strabismus by the modified Krimsky test, the examiner uses loose or bar prism to eventually center the displaced corneal light reflex in the deviating by trial and error, placing the appropriate prism over the non-deviating eye.
Children sometimes develop an abnormal head posture called torticollis (Figure 5), and their families are asked by the child’s pediatrician to have the patient evaluated by a pediatric eyecare specialist to determine if the head position is being driven by strabismus or some other abnormality of binocular vision.
The strabismus measurements required to diagnosis an ocular abnormality in this situation are not always possible in younger children. But one of the quickest and easiest ways to rule out an abnormality of binocular vision is to do a patch test. Simply place a patch over one of the child’s eyes and observe for 60 to 90 seconds, asking the parents to restrain the child’s arms if necessary to prevent her from removing the patch. If the head posture improves, this is suggestive of an underlying ocular abnormality of binocular vision and requires further assessment and more detailed measurements.
If the torticollis does not improve, this is suggestive of a non-ocular, perhaps musculoskeletal abnormality, most often of the sternocleidomastoid muscle on the side of the neck toward the head tilt.
If the clinician is going to try to measure vision in young children, it’s important to first have an understanding of what is considered normal, or age appropriate visual acuity in the pediatric population. Is a baby born with 20/20 acuity? Not at all.
Birch and coworkers estimated, through preferential looking techniques, that vision at birth is somewhere around 20/600, developing rapidly in the first year of life and improving to approximately 20/60 by 12 months of age, and reaching an adult normal of 20/20 by 60 months or 5 years of age.7
Newborn children are by definition visually inattentive and immature. They will, however, blink to a bright light shown close to their eyes.
Their eyes will also pop open suddenly when the room lights are flashed on and off, a reflex some clinicians call eye popping, which tends to disappear by around 6 months of age. Some children will also respond with saccadic eye movements to the rotating stripes of the optokinetic drum. This is just about all you can expect from a neonate in his first several weeks of life.
Intermittent strabismus may also be observed, but it should not be present by 2 to 3 months of age, correcting for prematurity. Pupils become active, and accommodation begins by 2 to 3 months of gestational age, which you can demonstrate by showing the child a target that stimulates accommodation, the multi-colored lights of the Worth 4-Dot flashlight, for example, and observing the constriction of the child’s pupils. Mid-dilated pupils sluggishly responsive to light by this age predicts reduced visual acuity for age.
Nystagmus in this age group suggests abnormality of the anterior visual pathway, while the absence of nystagmus in an otherwise visually inattentive neonate is suggestive of cortical visual impairment, or impairment at the level of the brain.
As children approach 6 months of age, they become extremely visually attentive in the near range, preferring faces over objects and toys. They will sit on their parents’ laps and stare at you with an astounding aplomb.
Acuity can be assessed for this age group in a number of ways, including forced recognition grated acuity tests like Teller Acuity Cards (Stereo Optical) and by observing how they fixate on and follow silent flashing targets, like a flashing toy star, through a smooth pursuit with each eye.
This is typically an abduction movement out toward the ear followed by adduction back again toward the nose, without losing fixation. Repeat if necessary. Last, but certainly not least, if all else fails, they can fixate on and follow the examiner’s face through the same smooth pursuit movements!
One can also take advantage of the vestibular ocular reflex to assess the visual pathways by taking the child (make sure you ask for permission from the parents!) and holding her up in front of you at eye level, face toward you, spinning around gently in one direction on a rotating stool.
This motion stimulates optokinetic nystagmus (OKN) through the inner ear. What you will see is the child doing a smooth pursuit in the opposite direction of the spin as she watches the environment rotating by behind you, then a fast saccade back in the direction of the spin, repeated over and over again until you stop spinning.
At this point, a child with intact visual acuity may exhibit a beat or two of residual OKN, dampening in less than 5 seconds. But in a child with decreased or absent visual acuity, the OKN will not dampen and persist for more than 5 seconds.
Preverbal children from 6 to 24 months of age can be presented with a base down prism in front of one eye, typically 16.00 or 18.00 PD. With both eyes open, this creates a vertically diplopic second image of a target at distance or near fixation. This is called the induced tropia test.8 If vision is intact, and the child is not suppressing visual input from the eye behind the prism, you will see a vertical, hypertropic shift in both eyes as the child attempts to fixate on the second image that appears above the original fixation object of interest. Absence of induced vertical shift is suggestive of amblyopia in the eye behind the prism. This can be documented in the chart as C for central (the eye is straight), S for steady (no nystagmus), and M for maintained (fixation through the prism), or CSM. If fixation is not maintained for more than one to two seconds, you would document this as CSUM, for Central, Steady, Un-Maintained.
Testing recognizable optotypes, whether Allen or Lea symbols, HOTV or Snellen letters, can begin from 30 to 36 months, depending on the cognitive ability and cooperation of each child. The author’s personal bias, based on 15 years of clinical experience, is not to attempt recognition acuity before 36 months due to variability of maturity.
Of course there are always exceptions to every rule. This age group will also peak during the test, so occlusion of the untested eye needs to be with special occlusive glasses designed for visual acuity testing in children (Figure 6), or adhesive tape directly over the child’s eye, or on the lens of his glasses.
Single surround bars, also called crowding bars, expedite testing in the younger children and have been shown to accurately replicate the resolution challenge of linear optotypes in amblyopic patients while minimizing test time in our most inattentive patients.9
You can help the child stay engaged by turning the matching card to the blank side and advancing to the next letter. Point at the screen and ask the child to look at the screen, then flip the card over to show the choices and ask the child to match the shape she sees.
From age 4, HOTV crowded optotypes can be used with good reliability, though every child is developmentally different, and sometimes the examiner has to resort back to a matching version of the test. Most children will progress to full Snellen recognition optotypes by age 5, though I tend to minimize the attention required with linear Snellen acuity testing by using the single surround, crowded optotypes until age 10, again, depending on the child, maturity, and intellectual abilities.
An important part of any complete eye exam, this component of the encounter, while straightforward in adults, can be challenging in inattentive children. A direct ophthalmoscope is often helpful if you have a less than cooperative child because you can illuminate the pupils from a more remote distance and see a red reflex in addition to the corneal reflexes of the Hirschberg test. This is also very useful in patients with dark irides, as it makes the irido-pupillary border a lot easier to see, especially for those of us who are presbyopic!
The last step in the pediatric eye exam is arguably one of the most stressful for all parties involved-the patient, his family, and the examiner. It is the rare child who willingly submits to having stingy cold eye drops put in his eyes. That said, there are a few techniques that will foster cooperation, help minimize stress, and overall make the process of instilling eye drops less tumultuous for the patient, his family, and you as the examiner.
My favorite technique is the “blink them in” technique. I explain to the child that we need to put eye drops in her eyes. I then direct her attention to a playful sticker attached to the ceiling above her head. I ask her to tilt her head back, then close her eyes, which is exactly opposite of what she is expecting you to say.
“Close your eyes tight, and I’m going to put the cold water on your eye lashes,” I tell her. This seems to be accepted by most children. “And when I count to three, we’re going to do a big blink, really fast.” I give her a tissue and tell her that she can wipe after she blinks. I also gently hold the child’s chin up until she blinks to avoid the drops streaming off her face and into her lap. I explain to the parents that while this is a messy technique (drops run all over the place, usually on the child’s clothes), it really works. Give it a try.
Another technique is the “kangaroo pouch” technique in which you cajole the child into looking up in a similar manner and at a similar target as described above, then place the drops in cul-de-sac of his lower lids. Our corneas are highly sensitive, so plopping several large drops in the center of someone’s cornea from 3 or 4 inches away is jarringly uncomfortable at best.
The lower lid cul-de-sac is much less sensitive, and a great place to instill an eye drop. I don’t have as much use with this technique in the younger children, but it does work well with older children and teenagers.
Despite these techniques some children, especially infants and toddlers younger than 36 months of age, will not cooperate with instillation of drops. In these cases, it is necessary to restrain the child in order to properly instill the drops. In doing so, you will first want to explain to the child’s parents why you have to restrain the child.
Once the parents agree, small babies and very young children can be placed on their backs on the right arm of one parent seated in the exam chair, the child’s head toward the crook of the parent’s elbow, feet across the parent’s lap. Have the parent hold the arms (babies have an incredibly accurate swatting reflex against threat to their eyes), while you take care of the head, lids, and instilling drops.
In older children, or bigger, stronger kids who require restraint, there is a real risk of injury to the parent, the child, or even you as the examiner. A different technique is recommended for these kids.
Have the child straddle the parent’s lap facing toward the parent, with one leg on either side of the parent’s hips. Position yourself seated directly in front of the parent’s knees, ask the parent to lean the child backward onto your lap so that he is prone on his back on your legs and his head is in your lap, facing up at the ceiling. You can now ask the parent to restrain the child’s arms and hands with their hands, the legs are immobilized around the parent’s hips, and you have both hands free to restrain the head, manipulate the lids, and instill the drops.
Lastly, it is extremely important for the technician to control the dosing of dilating drops instilled in the eyes of young children because these medications can be toxic10, trigger seizures11, and even lead to cardiac arrest12 in neonates and small children. Let’s break it down by age group and discuss what drops are safe and efficacious to use in this patient population
For newborn babies and children younger than 6 months of age, one drop of cyclomydril (Alcon), which consists of cyclopentolate hydrochloride 0.2% and phenylephrine hydrochloride 1%, is my drop of choice. In children with darkly pigmented irides, I add an additional drop of tropicamide 1% because it is a better midriatic drop, though on its own, a poor cycloplegic agent.
Starting at age 6 months of age and progressing to age 16, instill cyclopentolate 1% drops in lighter-pigmented eyes, adding tropicamde 1% or phenylephrine 2.5% drops for more darkly pigmented eyes. Some children who have had laser photo-ablative surgery for threshold retinopathy of prematurity may require all three drops to dilate adequately enough for the physician to see into the eye.
The causes of decreased vision in children, in addition to amblyopia and refractive error, include developmental malformations and acquired lesions of eyes and visual pathways. Clinical markers and signs include the oculo-digital sign, a habitual pressing on one or both eyes by the child with their finger or fist.
This behavior is specific to bilateral congenital or early-onset blindness due to retinal diseases and heritable retinal dystrophies, predicting best-corrected visual acuity usually 20/200 or less in the affected eye. Index of suspicion should be high in children greater than 6 months of age who do not readily make eye contact with you as an examiner.
Congenital nystagmus is commonly seen in disorders of the anterior pathways, such as ocular cutaneous albinism, which involves the optic nerves. Look for a compensatory head posture, implying optimal acuity, binocularity, and functional vision. Nystagmus is typically absent in cortical visual impairment (CVI). Large, slow, roving nystagmus or eye movements are often associated with poor vision and/or visual loss before the age of 6 months. These types of eye movements are not seen in CVI.13
There are many challenges associated with examining children in the eye clinic. Indeed, it is one part science, two parts art, and mastering the required skills takes skill, patience, practice, having the right tools, and perhaps above all, having the right attitude.
After a challenging session with any child, end on a high note and reward her for a job well done, after making sure that is fine with her parents, with a lollipop, or a playful sticker she can wear out of the office when she leaves. Treat your pediatric patients the way you would want someone to treat your child, or you, for that matter. Use dignity, empathy, and respect, and they and their families will remember you for it.
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11. Demayo AP, Reidenberg MM. Reidenberg Grand Mal Seizure in a Child 30 Minutes After Cyclogyl (Cyclopentolate and 10% Neo-Synephrine (Phenylephrine Hydrochloride) Eye Drops Were Instilled. Pediatrics. 2004 May;113(5):499-500.
12. Lee JM, Kodsi SR, Gaffar MA, et al. Cardiopulmonary arrest following administration of Cyclomydril eyedrops for outpatient retinopathy of prematurity screening. J AAPOS, 2014 Apr;18(2):183-4.
13. Brodsky MC, Baker RS, Hamed LM. Pediatric Neuro-Ophthalmology. New York: Springer Press, 1996.