Child Eye Chart
Home measurements are better than the optometrist shop. Let’s see why.
If you spend time reading the myopia blog, you are probably already familiar with my stance on eyesight measurements done at the optometrist shop: I am not a fan.
Let’s preface all else by stating that I do believe that eye checkups by a professional are a good idea.
Professional though, means going to an ophthalmologist, someone whose location is not dominated by prescription sales retail. As a general rule, avoid places that give you free or discounted eye checkups, while displaying a vast number of fashion frames in the storefront. It is much like the ‘free brake inspection’ at the franchise automotive brake shops. Do you think they’ll ever tell you that your car’s brakes are perfectly fine? If you haven’t seen my (slightly sarcastic) post on the myopia retail business, visit this blog post.
So, let’s keep the annual checkups with an ophthalmologist who isn’t relying on selling glasses for income. It may cost a bit more, and you are likely going to ignore their myopia conclusions – but for other eye health aspects, it is a wise precaution.
The measurement of myopia degree of your child though, you should do yourself. Let’s look at why this is:
Results vary based on environmental factors.
Peripheral vision, contrast, ambient lighting, subject lighting. All of it affects the sharpness with which your child will perceive the eye chart. This will vary for each child, too. You can test it, by doing the eye chart (more on that in a bit) in a brightly lit room (which is incidentally the correct way to do it). Then, do it in a completely dark room, with just the chart illuminated (how most myopia retail / optometrist shops like to do it).
If you do several readings, you will likely find that your child gets better results in the bright ambient setting, than the dark peripheral setting. This is entirely normal. Our vision depends on a number of factors, and is often notably affected by lighting, even if it is just peripheral.
This is one of the reasons I recommend not doing close-up work in a dark room.
The first takeaway then, is this – eyesight strength varies. Getting a single measurement, and a permanent focal plane change prescription (glasses) based on that one measurement, is completely unwise. It is fast, it is economical, and overprescription gives us a nice (though deceptive) ‘instant improvement’ result. So that’s what you get, if you go the retail route. Fortunately, the home measurement is more accurate, and offers several other benefits. More on that, later on, and in future installments.
Results vary based on physiological factors.
Stress. Physical exhaustion. The sugar content of the most recent meal. All of it will impact how well a child can read an eye chart. It is one of the reasons we will do more than one or two readings – we will do them regularly actually, which will help you better understand what is impacting your child’s vision.
Individual physiology varies widely. I personally can go from 20/10, to 20/30 in just a matter of a poor judgment party weekend. Weddings, and the related sugar and alcohol consumption, some lack of sleep, a marathon Sunday to catch up on work – my own eyesight is worse by several magnitudes.
Likewise, a child is affected by the nature of his/her day. You may easily get as much as a full diopter in variance, if you compare the very best result, with the very worst. Take a bright ambient light reading, in the morning before breakfast, with a happy, relaxed child – and then compare it with a spot lit chart, in a dark room, at the end of the day after dinner (with a cranky child).
This can be the difference of no prescription, or a -1D prescription as far as the optometrist is concerned.
Unfortunately, they don’t make this distinction. Your appointment might well be at 5PM, with a cranky child after a fast food meal, and probably in a dark room. There, your actually healthy eye sight child just got his/her first (and probably unnecessary) prescription. It is all downhill from there.
Results vary based on eye strain.
Eye strain is just another physiological factor. But it deserves it’s very own heading. You can loose 20% of your accommodation ability in a single day. Just spend all day glued to a computer screen, drink a lot of coffee, go home, try to read an eye chart. The results may not be pretty (unless you have really excellent vision to begin with).
Your child may spend all day playing video games on an iPad, watch TV, read comics. Add a bit of homework, and a big insulin spike dinner, and then try to have him/her read an eye chart. Again, things may not look nearly as good as they would in the morning, before all that close up strain (and dietary handicap).
The close-up strain is our main enemy. We need to keep that in check, and we will use the eye chart to illustrate, specific to your child’s case, how much that strain affects his/her vision.
Let’s get to the actionable portion of this installment:
What can you do, today?
We will use more than one way to measure eyesight. The eye chart is option number one. In a while I will introduce you to another way, which takes some more factors into account, and is in some aspects even more accurate.
For the full instructions of eye chart usage, see this post.
Look around Amazon.com (or ebay, for extra options), for a chart you like. There are child versions, and ones that do not use the standard letters (Snellen test). You may want to get more than one chart, just to keep interest levels high. With children, even if they are doing well, there is value to entertainment. We don’t want to turn this project into a chore – it should be fun, as much as possible. Animal eye charts, superhero eyec harts, whatever you think will work best, get one or two.
We will use this tool, and other measurement options later on, to keep track of a few things:
So, let’s get a chart or two, and attach them in a brightly lit part of the house. Keep in mind to keep this light and fun, low key, and not excessive in application (there is no need for daily eye checks – a few times a month is plenty).
Consider participating yourself, especially if you work at a high eye-strain job, or have glasses yourself. As the parent, setting an example is often a good idea (though this does depend on your specific situation and preferences).
If you have questions, please drop a note in the forum.
Cheers,
-Jake
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