Pretest Equipment

Have you ever wondered what those new crazy machines at the eye doctor do?

It seems that these days, when you go to the Optometrist, the pretest room has become more crowded than a NASA HQ as you are asked to put your face into yet another machine. What in the world does each instrument tell about your eyes? Technology has certainly evolved over the years!

Let’s begin with the gold standard tests. Everyone has been asked to watch that farmhouse, or hot air balloon, as it goes in and out of focus. Luckily, we live in Indiana, so those targets certainly are appropriate! This machine measures the curvature of the front part of your eye, along with the length of your eye, and in turn gives us a starting point for your refractive state, aka glasses prescription. The target going in/out of focus simply serves to keep your focusing system in a relaxed state, which results in a more accurate prescription.

You may be seeing less and less of that air puff test. The ‘archaic torture chamber’ actually measures the speed at which the air bounces off the front part of your eye, and that tells us how hard your eye is, aka how much pressure is inside of it. That test has been dreaded for ages, and thankfully, smart optical engineers have been listening. It has evolved into a new and improved handheld device that measures your eye pressure with a super tiny probe that yes does actually touch your eye, but it is super tiny and so fast you truly don’t even feel it. I’m almost nervous to share that secret as I may have ruined the mystique.

So many more technologies to share in upcoming editions. Stay tuned for parts 2 and 3 in your next editions of Current in Carmel.

Visual Fields and Retinal Imaging

Continuing to explore the instruments you may encounter in the pretest room at your optometrist office.

These next two instruments have been around in some form or fashion for years, but they are also evolving.

The visual field is that test where you press a handheld clicker whenever you see the squiggle (frequency change) in your side vision, or an actual light depending on the machine. Here, we are testing how far out, and at what sensitivity, you can see a visual stimulus without moving your eye. This is the quintessential test for not only glaucoma, but other conditions such as brain tumors, brain injuries, stroke, medicine toxicity, etc. It can be tedious to test, and scary to know what it is looking for, but new advances are making it fun, easier, and faster. You can expect to start running into a super cool, yet still super accurate, virtual reality headset version of this in the near future! A far cry from the old days when we used a giant bowl and the technician had to stand behind it and manually move a target, requiring tons of time, coordination and skill!

Everyone loves a good snapshot of their eyeballs, right? Retinal cameras have come a long way, but you will still notice a bright camera flash. If you are asked to smash your face against a giant machine, it is called the Optomap. You may not enjoy the quick flash, but be thankful for it. Getting that close to the camera face allows a much larger field of view, much like how the closer you get to the keyhole of a door, the more you can see of what is on the other side. With Optos, we can view up to 200 degrees of the inside of your eye, which is quite impressive! This technology allows a thorough examination without having to use the dreaded dilating drops in most cases. Your day should not be ruined by an annual eye exam!

Macular Degeneration Screenings

We would like to uncover two more tests you may encounter at your Optometrist’s office.

Both are significant in detecting early forms of Macular Degeneration and other ocular diseases.

Another flicker/clicker type machine now exists, similar to the visual field, that we are all accustomed to. It is called the MPOD, macular pigment optical density tester. This flicker varies in intensity, is circular and is mostly in the center of your field of view. It is actually measuring the amount of protective pigment you have in your macula based on the sensitivity at which you can detect various wavelengths of light. This is very important to know as we have learned that blue light coming from all of our devices may also be damaging to our eyes. The sun is no longer the only offender! When this value starts decreasing, we must consider measures to boost up the good pigment that absorbs these harmful high energy short wavelengths of the light spectrum. Similar to sunscreen, the more pigment and protection we have, the better.

Optical Coherence Tomography: Fancy word, acronym OCT. This machine has been around for some time now, but was mainly utilized by specialists during diagnosis and treatment of many eye diseases. It allows the retina, and other structures of the eye, to be viewed cross sectionally at a microscopic level. In other words, it is like slicing through a piece of lasagna to view all the layers. It is now becoming standard of care, and OCT may even become part of the screening process in your pretest room. Why shouldn’t it? It is the best anatomic map and really pulls all of the puzzle pieces together when viewing all of the images of the surface of the eye together. You will know you are behind the power of the OCT when the AI of the machine itself begins giving you instructions.

We hope these brief intros to Optical Tech can give you a better understanding of all of the details and importance that go into your eye exam pre testing instruments.

Yes, there is a LOT more that goes into your annual eye exam than just asking “is it better 1 or 2?”

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