Eyedolatry

Crash Course in the Young Pediatric Examination

Giving an eye exam to a screaming 2 year old with zero attention span may be the least exciting part of your optometric day. But I am here to offer you my quick and easy guide to making the most of the 5-10 minutes of information retrieving you may be at the luxury of obtaining. Here's my quick and easy guide to making the most of your toddler or challenging pediatric exams.

History

I tell my technicians when I see a young toddler on the schedule that if they don't get any single piece of information before the patient sees me, at least talk to the parent about what, if any problems they have noticed at home. Your patient's parent has been looking at their child's eyes for years, and they will have noticed unusual behaviors like eye turns, or frequent eye rubbing. If the parent doesn't know, ask about preschool teachers or daycare providers. Have they said anything about the patient's eyesight or behavior?

EOMs

I like to start by making my examination seem more like playing a game. "Can you follow this pen/stuffed animal/interesting object?" Games are engaging to children and will grab their attention as a first task. You can very accurately get a good feel for EOMs with this method. I will also push the target in towards their nose --"can you follow it towards your nose?!" and I just got a push up convergence reading.

Ocular alignment

Cover testing can be a real challenge, but I have had success with a "staring contest" method. "Have you ever played a staring contest? Look right at the tip of this pen/animal's nose/etc and I am going to try to distract you, but don't take your eyes off it!" Sometimes as I use my hands or an occluder to cover and uncover the eyes, the child will be too distracted, and this method will fail.

No worries, you always can fall back on Hirschberg. Remember, for every millimeter of decentration in the light reflex, that is 22 prism diopters of misalignment!!

Classic Bruckner test. The white reflex is abnormal! via

Pupils

If you just did Hirschberg, this is an easy transition. You already have a light in hand to check pupils. My advice, get in and get out fast. Children don't love lights being directly shone in their face. I will often have my direct out for Hirschberg, do a quick pupil testing, and then end with Bruckner's to help me prepare for retinoscopy.

Bruckner's test take home: If one eye is brighter/lighter then it is either deviated (strabismic) or amblyopic in some way. Darker red reflex is normal. Brighter is Bad.

Vision

That's right, I don't start with vision. I find that usually checking vision is not fun for patients, and they get bored reeeaaally fast. How much technical information you can get really depends on the age of your patient and their level of cooperation. Maybe they can read a few pictures for you. Maybe they know A, B or C. Tumbling E chart is also an option if they are ready to cooperate. I find that usually in 2-5 year olds, I can get relatively good results with a picture chart using the cake, chicken, hand print, and plane characters. Good luck on that telephone and car. But you may get inventive responses if you want a good laugh. In infants, having Face Dot paddles are a great tool. But if you don't have that luxury, just getting the patient to respond to any visual stimuli -- a stuffed animal, a colored block. Anything is better than nothing. I like hiding a toy behind a piece of paper, and then bringing it out from behind. Infants will find a toy much more fascinating to look at than a blank paper. If they can see it of course. Many times they will just look at your face the entire time, but that is useful too. If they smile when you smile and make faces, this is also a measurement of vision!

Retinoscopy

Skiascopy Bars--my best friends via

This is really the bread and butter of your exam. There is a good chance after retinoscopy that you are going to get zero other useful data. But you really need to have this. I like performing retinoscopy prior to dilation, but if it is just not happening, go ahead and skip to cycloplegic insertion and take a 30 minute break.

Sure it is ideal to have the patient look at a target on the wall, but that is usually not going to happen. It is so much more interesting for kids to look right at your light. What's the solution? Mohindra of course.

Turn the lights down dark, and just let the patient look at you. I love my skiascopy bars for this; good luck if you are in the phoropter for a two or three year old!! Now remember, the patient is fixating on you, so you need to take that into consideration when you determine the actual Rx. The rule of thumb is take your reading, and adjust -1.25D from that for your final Rx.

Why? Dr. Mohindra was a brilliant and very petite female doctor. She had short arms, and a small working distance for her retinoscopy as a result. So if she used a 40 centimeter distance to scope (+2.00D), and the patient was fixating on her scope, if the patient has a normal accomodative lag of +0.75 D then you should adjust the Rx by -1.25D. Follow me? (thank you Dr. Alan Fors for these entertaining optometry histories).

If you didn't fully follow my poor attempt at explaining Mohindra's magical 1.25D adjustment, just remember that is a rule of thumb, but would not be accurate if you scope at other than 40 cm. If you have long arms, don't adjust -1.25D. Adjust your Rx according to your normal retinoscopy adjustment with that 0.75 near lag taken into account.

Yes, it is nice to get a near retinoscopy here too. But be practical. Getting something is better than nothing, and you will able to tell very quickly how much cooperation is occurring on the other side.

ADDENDUM: Cycloplegic Retinoscopy

If you cyclo, you also need to take into account the change in Rx from the accomodative system being entirely knocked out. As a rule of thumb, many doctors suggest cutting about 1.00D from hyperopic Rxes after cyclo and adding -0.50D to myopic Rxes after cyclo. Example: If you scope a +5.00D with cyclo, prescribe a +4.00D. If you scope a -3.00D, prescribe a -3.50D.

Slit Lamp Exam -- I mean, a direct scope and your 20D lens

If you can get your young pediatric patient into a slit lamp, well you just may be a magician. I find that a transilluminator or direct scope with a 20D lens is usually quite effective. You can see large corneal scars, conjunctival growths, and even papillary reactions under the eyelids quite easily. And kids are sometimes interested enough to try to look through that big magnifying glass to hold still for a few seconds. This is also a good time to do a digital IOP measurement if you weren't able to get NCT in a work-up. Just palpate gently through a closed eyelid to test for symmetry.

Internal Exam

Even with dilation, evaluating the internal eye is difficult. Sometimes the best I can get is a red reflex confirmation -- but that is something. Really the important thing to find here are developmental defects like coloboma, or ocular tumors that will be quite obvious (white instead of a red reflex). If you can't perfectly grade that C/D ratio, there is always next year.

I know this is not the ideal exam that I just wrote about, but this is the practical way I collect data and if needed, prescribe glasses for my very young or very uncooperative infant and toddler exams. Just simplify your testing, maximize your short amount of time where the patient pays attention to you, and don't be afraid to abort if a particular test isn't working. Inventiveness and flexibility is so important with kids. The rapport you build with your young pediatric patient in toddler years is going to make those elementary age exams so much easier, because you will have established the eye doctor as a fun and not scary place to be. And if a toddler or infant is really having problems with ocular development, you will have found the problem before it can interfere with learning to read and write. Take the time to do these exams, because perfection isn't required. Just get the best results you can from what the child allows, and even with the most imperfect five minutes of testing, you would still be able to find life-threatening or vision-threatening problems because that is what all of those years of optometric training prepared you for!

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Newly Discovered Dua's Layer has role in Glaucoma

dua's layer and trabecular meshwork 1:38 PM

Yes, if you Google a diagram of corneal layers this image is the first to
come up. No, it is no longer correct. Not even Google can keep up! via

Remember when we all thought the cornea was just five layers thick? These were simpler times, when diagrams were neatly organized and mnemonic devices were memorized -- the ancient history of pre-June 2013. That was when Professor Harminder Dua of the University of Nottingham first published his discovery of a layer just 15 microns thick between the corneal stroma and Descemet's Membrane which he named Dua's layer. The thin corneal layer is surprisingly tough, able to withstand up to 2 bars of pressure. Due to it's properties, it has been used as a guidepost for surgeons in corneal transplants, banking on the toughness of Dua's layer to determine the depth of their incisions.

Dua's layer has also been implicated in corneal hydrops, a condition where fluid rushes into the layers of the cornea causing pain and sudden vision loss, most commonly in keratoconus. A tear is Dua's layer appears to be the cause of corneal hydrops and the fluid that rushes into the stromal layers to cause so much damage.

But what else since its' discovery has Dua's layer done for optometry? In just a short amount of time, Professor Dua's research has revealed that the trabecular meshwork is really an extension of Dua's layer. The trabecular meshwork is one of the most important tissues of concern in treating glaucoma, a disease of the eye that can result in permanent blindness. Trabecular meshwork is a tissue in the anterior chamber of the eye through which aqueous humor passes to be drained out of the eye via Schlemm's canal. If the fluid gets backed up, pressure will spike inside the eye, which can be high enough to kill nerve fibers at the back of the eye (glaucoma is a disease of optic nerve death). Many of today's best treatments for glaucoma work on increasing outflow of the aqueous humor fluid through the trabecular meshwork -- making that drainage occur faster and more effectively.

Just a year ago, none of us knew Dua's layer existed, and now we have learned that it extends to form the trabecular meshwork, a tissue that we all actively utilize in eyecare for glaucoma treatments. It is amazing to think how much there still is to learn about the eye, and how much our knowledge changes every year. I will keep you posted on every amazing detail on this blog, and I am never at a shortage of material with how even our understanding of basic eye anatomy is changing from year to year!

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Myopia May Be Reversible?

blue light may revers myopia 9:35 AM

Chicks have long been used to help investigate refractive error
development since their ocular model closely resembles the
development of our own via

So little is really understood about the progression of myopia (near-sightedness). Many of my patient's parents are quick to blame computer games and the large amounts of homework required by schools as to why their children's vision is getting worse from year to year, but these culprits are too simplistic. Genetics, environmental influence--it seems to all be connected. But new research points to a surprising new potential culprit -- light.

Around 2011 several reports came out linking myopia to reduced sunlight exposure in studies performed with baby chicks. Sunlight, it appears, increases the rate of release of retinal dopamine, which inhibits growth rate of the eye. Myopia is a result of light falling in front of the retinal photoreceptors, most often due to a longer than normal eyeball. The more the eye grows, the more near sighted a person will be. Researchers suggest 10-14 hours per week of outdoor light exposure may help slow myopia progression, but more studies need to be performed for this effect to be truly demonstrated.

A new study published in December takes our understanding of light's effects on myopia to a new level. In their experiment, Foulds et al separated baby chicks into red light and blue light exposure groups with a 12 hour on/off cycle for a period of 2-6 weeks. The results were amazing -- the red light group showed marked progressive myopia and the blue light group showed progressive hyperopia (far sightedness). And then they did something even more impressive -- by putting the red-light raised chicks with now high-induced levels of myopia in blue light for 3 weeks, they reversed the myopia. The same held true for reversing the hyperopia.

So what does this mean for us? We are a long way from putting your child under blue light for 12 hours a day, but we are beginning to understand what is happening on the neurologic level of the eye when refractive error is created. So many of our methods of reducing myopia have shown limited response, but maybe the future looks brighter. If you are worried about your child developing high levels of near sightedness, my best recommendation to you is get them involved in outdoor sports. Wear proper sun protection of course, but the more time spent outdoors with ambient light levels, the better your child's chances look for a lower prescription!

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