Time and time again, I am amazed at the little things. The little things in this case are the little mistakes we make when evaluating the eyes of a child. I am a pediatric optometrist in San Diego, and I receive a number of applicable referrals from fellow eye care providers, which I proudly entertain. What shocks me is the number of referrals that come from pediatricians regarding a child who has, in fact, already been seen by an optometrist. Apparently, something had been left undone.
First and Foremost: Vision
A child’s visual acuity will either give you confidence or evoke the puzzlement that will encourage you to discover the yet unknown. You may breeze through the examination of a 20/20 child, knowing that amblyopia is not an issue. However, the 20/50 child has already informed you that much more work must be done. Let the acuity be your investigative guide. First step: Pick an eye chart. Start with a standard age appropriate chart. At age two, I use Allen Cards and expect a best-achievable acuity of 20/30 in each eye. At age three, I use HOTV matching and expect acuities of 20/20 in each eye. At age five, I introduce the Snellen chart. If the chosen chart proves to be too challenging for that particular child, simplify each chart by isolating an individual letter. Isolating the letter eliminates the crowding effect and makes the letter easier to identify. At the follow-up visit, you can raise the bar by pushing the child to read the full line.
There are times when a cognitively appropriate chart must be used. In my practice, I have seen the extremes. I have encountered a three-year-old who can almost read the name of the manufacturer on the near point card. On the flip side, I care for children with variable developmental disabilities who have not learned the alphabet, even at age 10. Ask the parents or guardians if their child can identify letters, how confident they are with letter recognition, or if a picture chart would make them more apt to respond?
If a child struggles with the Snellen chart, isolate the letters. If isolated Snellen letters puzzle the child, switch to an HOTV chart. Still struggling? Again try isolating the letters on the HOTV chart. If the child is not at all comfortable with letters, try Allen Cards by first introducing the picture cards within reach of the child’s hands.
What if the child cannot or will not identify the pictures? If the child is developmentally delayed or non-verbal, document vision by noting whether the child can fixate on an entertaining object. Using a finger puppet, note whether the child can follow the target or if the child can only maintain fixation on a central target. Document each of these as “Fix & Follow” and “Central Steady Maintained” respectively. The ability to fix on a target and follow it is normally present between two and four months of age.
Lastly, give the parent or guardian some homework. Just as one visual field is insufficient data for a clinical decision, one visual acuity measurement is also inadequate.
Dispense a copy of the appropriate eye chart you wish to use at the following visit. Whether you dispense copies of the HOTV chart or of the Allen Card pictures, you are granting the child an opportunity to become familiar with the test. Better yet, the test now becomes a game.
But, what if the parent reports a suspicious eye or head turn that you cannot reproduce at that first visit? More homework is required. Instruct the parent to bring in photos demonstrating the eye deviation and/or head posture. (That is if they didn’t already show you photos on their phone.)
Do Not Fear Cycloplegia
The number of drops and the time required for absorption depends on iris color. The darker the iris, the slower the absorption.Lighter irises reach full cycloplegia faster and achieve a larger dilation.
Children have large accommodative amplitudes. Thus, a child who is only slightly myopic can appear to be significantly near-sighted when accommodating. If you over-prescribe, you––the doctor––could be the cause of their amblyopia. If you under-prescribe, their eyes are likely to continue to intermittently deviate inward. The only way to accurately measure a child’s refractive status is to control accommodation.
Enter cyclopentolate! Tropicamide is a good dilator, but not a strong enough cycloplegic medication. Cyclopentolate, homatropine and atropine are all excellent at fully arresting accommodation. Although cyclopentolate is the drug of choice most widely accepted, no agreement exists regarding the ideal dosage for complete cycloplegia. My drug of choice is 1% cyclopentolate simply because it has the most rapid onset and the shortest duration. In my office, we use two to three sets of drops instilled about 10 to 15 minutes apart to achieve full cycloplegia.1 Full cycloplegia will take 30 to 45 minutes, and recovery can take anywhere from six to 24 hours (typically about 12 hours, but that will vary with iris color as well.) How do you tell when the child’s eyes are fully cyclopleged? Grab your transilluminator and your retinoscope. If the pupil is still moving or if you see a fluctuation in retinoscopic reflex, more drops and/or time is needed.
Serious side effects are extremely rare with the use of cyclopentolate eye drops. The common side effects that I routinely see include burning upon instillation, mild flushing of the skin and a mild increase in body temperature. Although very rare, cyclopentolate has been documented as causing a fast or uneven heart rate, severe skin rash, slow and shallow breathing, hallucinations, psychosis and/or seizures.2,3
Personally, I perform a cycloplegic retinoscopy on all new patients under the age of seven. Cycloplegia is also helpful in evaluating older children who exhibit an accommodative spasm on a dry refraction, any degree of eso-deviation, an unexplainable decrease in acuity and of course, latent hyperopia. In the developmentally delayed population, cycloplegic retinoscopy becomes a standard of care that may span a lifetime.
Remember the retinoscope? Use it and trust in your endpoints. I never use an auto-refractor. Retinoscopy in the pediatric population is a dynamic experience. I have yet to meet an auto-refractor that can bend and dance to the beat of most children who naturally have difficulty maintaining fixation. My retinoscope and my free trial lenses are my favorite tools by far.
Do Not Under-Prescribe
Once you have made an accurate assessment of your patient’s acuity, survived the drama of instilling the cycloplegic drops and have your wet retinoscopy lying confidently before you, what is your next step? Ask yourself, “Have there been any red flags just yet that necessitate an Rx?” And, if the answer is, “yes,” what do you prescribe?
I am often questioned at what age and at what degree of refractive error should the optometrist first prescribe. Given that your patient in question is completely asymptomatic and without any suspicion of strabismus, you can apply the following rule. The 1-2-4-2 Rule refers to 1 diopter of anisometropia, 2 diopters of astigmatism, 4 diopters of hyperopia and 2 years of age. Allow me to elaborate: If the cycloplegic retinoscopy reveals 1 diopter or more of anisometropia, I prescribe. If the magnitude of astigmatism is 2 diopters or greater, I prescribe. If the cycloplegic exam reveals 4 diopters of hyperopia or greater, I prescribe. If any of these refractive errors are present at age 2 or thereafter, I prescribe.
Keep in mind, this rule is based on cycloplegic retinoscopy, not on a dry refraction or an auto-refractor. This rule does not apply to more advanced cases, which involve any level of strabismus—nor does it hold up for children with low accommodative amplitudes. A cycloplegic retinoscopy greater than 2 diopters is a flag, but in my mind, the flag only becomes red at 4 diopters. For example, if a five-year-old, who is asymptomatic and does not have strabismus or amblyopia has a cycloplegic retinoscopy of 3 diopters, I would not prescribe. If, however, that same child has a micro-esotropia, I would definitely prescribe.
How to prescribe when other factors exist is a full article in itself and will not be discussed here. That said, I would not cut the astigmatism, nor would I cut the myopia. I choose not to soften any prescription. During the critical age of visual development, giving a child anything less than perfect clarity is an invitation to amblyopia. The first step in treating amblyopia is to prevent amblyopia.
Do Not Under-Treat
Do you remember the days of Melton & Thomas? (Not that we do not still thrive from their shared knowledge.) Specifically, do you remember their persistence in teaching the optometric community not to fear steroids? The treatment of amblyopia is no different. I still see patients with amblyopia that was documented as treated to a best-achievable vision of 20/50. Really, 20/50? The vision is sub-optimal, yet the parent informs you that they were very compliant with the doctor’s instructions to patch the fellow eye religiously for one hour every day. One hour of patching with a vision of 20/50, really? Thanks to the fabulous ongoing work by the Pediatric Eye Disease Investigator Group (PEDIG), amblyopia management no longer involves guesswork. We have the studies, so use them. Trust in your retinoscopy skills and in evidence based medicine. Check out the latest PEDIG findings at
http://pedig.jaeb.org/Studies.aspx.
We all know that there is a window of time, a critical period. Children are susceptible to amblyopia up until age six or seven.4 The exact age range during which you can successfully treat amblyopia is not as clear. Regardless of the child’s age, everyone deserves the opportunity to succeed or fail at treatment. It is your job as the eye care practitioner to diagnosis amblyopia and initiate proper therapy. If you act promptly and efficiently, all future eye doctors will marvel at this patient’s best-correctable vision and commend you for your dutiful care of that child. Most importantly, you will have given the child his/her best chance at binocular vision and 20/20 acuity in each eye. I have successfully treated amblyopia in children up to age 12. Why not try? Worst-case scenario: The child’s vision will be just where you first documented it. Best-case scenario: You have improved his/her vision for the rest of their life!
Still don’t know whether to patch or initiate atropine treatment? Personally, I have the child as well as the parent make this decision with me. It is their therapy—their vision we are saving. So, why not allow them to be part of the decision-making process and pick which therapy they will be most compliant with. Whichever path you chose, be certain to start with the most appropriate spectacles, if they are indicated. Second step: Have the child back for a follow up visit to re-measure the alignment and the acuity. This will be your baseline best-corrected visual acuity (kind of like your target IOP for all you glaucoma gurus out there.) Now, launch your treatment protocol and emphasize that compliance is critical.
Never assume that your patient has amblyopia—prove it for yourself. Let’s say you inherit a patient from a colleague. This sweet child comes to you with a diagnosis of amblyopia which was treated by a doctor back home. Where should you begin? At the beginning, of course! Do not assume because the parent or guardian tells you the child has amblyopia that you can now code it and write off that 20/50 acuity. Discover for yourself the cause of the amblyopia. Determine for yourself whether the degree of amblyopia does indeed match the degree of visual deprivation. Age of onset, age of diagnosis, compliance and appropriate therapy will all dictate the length of exposure to abnormal visual stimulus. The earlier the onset and the longer the duration without treatment, the more severe the vision loss will be.
Normal visual development is dependent on equal and clear retinal images. If that child comes to you with “lazy eye,” you must uncover the cause of the blurred retinal image. In a nutshell, look for three things:
• Clear retinal images. There should not be any pathology or media opacity obstructing the visual axis.
• Equal clarity. Cyclo, cyclo, cyclo. Rule out myopia, high hyperopia and astigmatism. Be very mindful of anisometropia. One little diopter—whether spherical or astigmatic—is enough to cause amblyopia.
• Proper alignment. Any deviation (unless alternating), even a micro-strabismus, will cause amblyopia. A child with strabismus literally turns off an eye at the level of the visual cortex.
Uncertain? Follow Up!
When things don’t add up, you have two options. Option one: You can refer to a colleague. There is zero shame in a referral as long as you correctly direct that referral.
Contact an optometrist or an ophthalmologist who specializes in pediatrics. Option two: Do not under-estimate the value of a follow-up. Not all children will cooperate on the specific date mom or dad booked that appointment. If you are struggling for an acuity reading or that cover test is questionable, simply book a prompt follow-up appointment and give yourself a fresh opportunity to look again.
Your biggest challenge is that a child will not tell you whether your treatment has succeeded or failed. You must trust your instincts, have faith in your knowledge and use the child’s best-corrected acuity as your guide. As previously mentioned (and hopefully ingrained in your memory), cycloplegia is the essential starting place.
There you have it—the little things we must never forget to best care for our little ones. Attain a solid acuity measurement, perform retinoscopy with a full cycloplegia, prescribe to the child’s fullest needs to achieve clear balanced vision and initiate prompt and full amblyopia treatment, when indicated. Your reward will be that child’s beautiful eyes staring right back at you.
Dr. DiLibero is a pediatric optometrist who practices at Kaiser Permanente in San Diego. She is a graduate of Pennsylvania College of Optometry at Salus University in Philadelphia.
1. Bagheri A, Givrad S, Yazdani S, Reza Mohebbi M. Optimal dosage of cyclopentolate 1% for complete cycloplegia: a randomzed clinical trial. Eur J Ophthalmol. 2007 May-Jun;17(3):294-300.
2. Demayo AP, Reidenberg MM. Grand mal seizure in a child 30 minutes after Cyclogyl (cyclopentolate hydrochloride) and 10% Neo-Synephrine (phenylephrine) eye drops were instilled. Pediatrics. 2004 May;113(5):e499-500.
3. Mydriatric eye drops: severe adverse effects in children. Systemic Reactions. Prescrire Int. 2009 Jun;18(101):123.
4. Helveston EM, Ellis FD. Pediatric Ophthalomology Practice. 2nd Ed. St. Louis: The C.V. Mosby Company, 1984.
5. Committee on Practice and Ambulatory Medicine, Section on Ophthalmology. American Association of Certified Orthoptists; American Association for Pediatric Ophthalmology and Strabismus; American Academy of Ophthalmology. Eye examination in infants, children, and young adults by pediatricians. Pediatrics. 2003 Apr;111(4 Pt 1):902-7.
