iris

The metaphysics of dilation

The metaphysics of dilation

Because I am an optometrist I dilate. Or is it because I dilate I am therefore an optometrist? In either case I am allowed, by law in Colorado, to use diagnostic pharmaceutical agents in the course of a patient examination in order to enlarge pupils. I’ve recently come to find out that there’s a wide range of the use of these drugs by others in my profession. My debate over the purpose of routine use of these diagnostics was made clear to me after 16 pages of discussion but ended more in how often a patient should be seen for a regular eye exam than how often a patient should be dilated.

First, the drugs. Dilating can be done with different chemicals. There are kinds that vaguely dilate pupils and others that can maximally dilate your pupils for a week or more. Why would one doctor use one drop and another doctor choose the stronger or weaker one? That, my friends, is based on your doctors training and beliefs or needs. You see, doctors are people. There isn’t one way to do things so we pick the way we personally want it done. And that’s ok. Here are a few types of dilating drops if you want to look them up: tropicamide, paremyd, phenylephrine (also found in some OTC redness relievers), homatropine, cyclopentolate and atropine. And most of those drugs can be in different strengths (ex., 0.5%, 1%, 2.5%, 5%, 10%).

In the 16 pages of discussion I finally got to the bottom line of when to dilate a healthy person with very low or no prescription who has no complaints or known medical conditions leading to eye disease. It would be done in their next recommended visit…..in 5-10 years! See the link below if you want to read the guideline. That lengthy period was an eye opener. Honestly, telling a patient to come back in 5 – 10 years basically sounds like we don’t want to see them again. But that’s what the guideline says. My own profession’s main association (American Optometric Association, AOA) says eye exams are recommended every 1-3 years for the same healthy individuals. That’s a conflict right there. There’s something even stranger about this. These vision plans that I accept, many times they allow an eye exam every year. There’s an incentive for everyone involved to possibly over-utilize health care here. And why not? Don’t companies want you to use things more often because they will make more money? That’s the American way.

Why dilate anyway? The main reason is an attempt to see the various “parts” of the back of the eye. We have to look through the pupils to do that, to see the retina, and the bigger the pupil opening the easier it is to see back there. It’s like peering into a mystery world that is unknown until we spelunkers go check.

Before anyone jumps to conclusions about what their eye doctor does or doesn’t do, you should be in good hands. This post isn’t about covering all the reasons for dilating either. Each doctor has their own routine for your routine eye exam. Just remember to tell them of anything you can recall about your eyes and vision. That will make it easier for your doctor to decide whether they may or may not dilate you. And just an interesting note about eye (iris) color….blue eyes generally dilate with less drugs than brown eyes and the length of dilation for blue eyes is also generally shorter but the same drop might work as well on both eye colors.

http://www.guideline.gov/content.aspx?id=25644

dilated vs undilated

dilated vs undilated

 

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Predicting eye color from DNA

Predicting eye color from DNA

Lately I’ve been curious about eye color. If you’ve seen some of my first few posts (there aren’t that many yet) I went over a few reasons why blue eyes are blue and showed an infographic that explained how iris color is determined. Well I found this webpage yesterday where a person posted their DNA results and what their predicted eye color should be versus what the person’s eye color actually is. I can’t confirm any of this and wasn’t sure about posting this but what the heck. It sounds interesting, the prediction was so accurate that it’s almost not believable.

Apparently the DNA results can be used to predict a phenotype….what you look like physically. I haven’t read what else this analysis can do but if it can predict eye color which requires a fair number of genetic combinations, I wonder if we could ever use DNA from, say, a baby, and then see what they might look like in 10, 15, 25 years. Now that would be cool. Maybe. What if you were the parent and didn’t like what your future child might look like or what if the predictions were some perfect human specimen for a sport or other career and then you tried to force your child into that? Maybe there are some ethical issues, as there are with a lot of things these days, that might either help or hurt how we “manage” our DNA and maybe even our offspring.

I’ve been tempted to try 23andme.com when I heard about it. They had some deal for $100 but not sure what it costs now. If you’ve done any DNA analysis like that, were you surprised at any of the results? The website I found apparently used a service called gedmatch.com to compare geneologies to DNA results. I’m curious what people find out and whether any of the information is useful or if it’s another way to take a few bills out of your pocket and to give you a little entertainment. Right now I bet it’s a little of both?

dna iris