I had the honor of being interviewed by Dr. Darryl Glover on the Defocus live stream last night. I was nervous and probably blabbered on a bit too much, but it was a fantastic experience and I really appreciated the opportunity to talk about my work on EyeDock and Eye Scholar.
My eight-year-old asked me to draw with him using some markers he got for Christmas. I thought I’d try to draw a phoropter without looking at a reference image (although - full disclosure - I have some practice illustrating phoropters).
Astigmatism is very common yet, for something that a LOT of people have, it’s very misunderstood. And it gets blamed for just about any deficiency people perceive in their quality of vision (and sometimes they’re right).
Perhaps this is because it’s a little tricky to conceptualize, or maybe it’s because the word itself sounds like it could be a horrible disease. If I didn’t know better, I certainly wouldn’t want to be told that I’ve caught a case of “astigmatism”.
When we try to explain astigmatism, we often do it by describing the shape of the front surface of the eye. “An eye without astigmatism is spherical, like a basketball. An eye with astigmatism has two curvatures, a steeper one and a flatter one. Kind of like a football.”
I think most people comprehend this analogy when they hear it but, like a lot of information, the passage of time eventually erodes this understanding and, years later, they only recall that there is something football-like about their eyes.
When I look at Edvard Munch’s The Scream, I like to think about what would make the subject of the painting scream. What could be causing the horrified expression on his face? What could be altering his perception of the world and transmogrifying it into a swirly, melty nightmare?
I can only think of one thing: Astigmatism.
Yes, the dreaded football-eye.
Why did I draw a picture of a Terminator refracting a Terminator?
I’ve been working on a tutorial to teach optometry students to refract a virtual patient, where my program would make the patient respond to questions and lens changes. At one point I started making a feature where, if the student got stuck or confused, they could turn on a “tutorial mode”. This was essentially another program that would try to think like the doctor to help walk the student through the refraction.
It suddenly struck me that I was pretty much trying to create a virtual doctor that would be refracting a virtual patient.
I’m pretty sure this is how Skynet got started.
To make a long story short, in the interest of saving humanity, I scrapped this plan (I certainly did not give up because it was proving to be too hard).
A Terminator using a phoropter to refract another Terminator.
ICO Matters Magazine asked yours truly for an opinion on the role of up and coming technology in optometry. You can read my response here.
I'm one of the little-head guys. The one on the left.
I've rewritten my contact lens calculator on EyeDock. The new version does a better bob of showing its calculations by displaying information on optic crosses. It's also more flexible with how it accepts keratometry and refraction input. Lastly, I've added a SPE / CPE lens calculator that uses Thomas Quinn OD's nomograms (the same ones we used to create the GPLI calculator).
Here's a little video introduction. I hope you find it useful!
- Todd
Admittedly, a refraction (the process of measuring a glasses prescription) can be a little stressful for a patient. Sometimes it's difficult to make a choice, sometimes both choices look back, and sometimes you might even say "one" when you meant "two". People fear that, if they make one wrong decision, they're going to end up with a bad pair of glasses.
In truth, this should not happen with a proper refraction because it's a very sound process that starts by breaking your prescription into three parts, the amount of nearsightedness or farsightedness, the amount of astigmatism, and the axis (or angle) of astigmatism. For each part we show more and less amounts of power (or axis) until one of a few things happen:
In my humble opinion, the most helpful thing to do while being refracted is to limit your answers to one of three things: Lens one is better, lens two is better, or they look the same. It doesn't matter if the one you're choosing is still blurry, sometimes that's the case. We just need to know which is the clear-er of the two. The primary goal of everyone involved is to clear things up, but that might not happen until the end of the process. When we ask which is better ("one or two") we're trying to find out which direction we need to move our power - up or down, or which way to twist our axis, left or right - to reach our objective of getting the best possible vision. Most other information besides "one", "two", or "the same" is extraneous. "Choice one is better, but it's blurry" doesn't really tell us anything beyond the fact that we need to move the power in the direction of choice one.
Optometrists learn to refract pretty quickly. Within a couple years we've done thousands of refractions and are quite proficient at it. We start to feel like finely tuned machines - if you say "one" we reflexively make our change in the instrument and ask our next question.
One thing that throws me off is when people don't tell me which choice they like, but when they tell me which one they don't like. On the surface it the distinction between the two seems insignificant. If there's only two choices, and you know which one is worse, then the other one is better, correct?
I was trying to figure out why this seemingly little thing seems to interrupt my flow so much. I was looking for something to compare it to, and I thought of another situation where you might have to make frequent choices between two options : Getting directions while driving. Sure, if someone constantly told me to "turn not left" or "turn not right" I could pretty much figure out how to get where I'm going but, the way my brain is wired, being told "turn right" or "turn left" is a lot easier for my brain to process.
All that being said, a good refractionist has to be flexible. To the best of our ability we need to educate our patients how to respond to our questions, and we need to alleviate their stressors and fears while being refracted. However, sometimes we just have to parse our patient's responses to the best of our ability and just do our best.
I just released a new app to the App store, and is now available to download. It's a Park's Three Step app, similar to the one I have on the EyeDock website.
It's been a long time since I made a new iPhone app. I wrote the original EyeDock and CLCalcs on a very early version of iOS (it was iPhone OS at the time). Back then, iPhones only had 3.5" screens and iPads didn't exist.
I've opened up XCode and modified those apps a few times since their inception, but mostly just to fix things. It usually worked like this:
My apps were pretty much like an old watch: I fixed them when they broke, but I broke out in a cold swear whenever I opened them up and looked at the insides.
I decided a few months ago I really need to make some changes to the EyeDock app. I don't like the way it downloads its data, it's not optimized for the 4" iPhone screens, and I really need an iPad version.
I'd stayed tuned to the developments in iOS and knew that things were evolving rapidly. In light of Apples has added or changed their APIs, in conjunction with the major changes I wanted to make to my old apps, I thought it might be best to relearn the ropes. What better way to do this than to make a new app from scratch.
In conclusion, I bring you the Parks Three Step app. It's my first universal app (it works on both the iPhone and iPad). I too advantage of many of the new things that have come along with the last 3-4 versions of iOS, including parallax, blocks, autolayout, and ARC. These things may not mean a lot to my non-iOS-developer readers, but this essentially means I'm caught up on the modern way of doing things.
Now time to rebuild that watch.
