Clinical Pearls
This is the gold standard for checking IOP!
Keep in mind this is one of the most difficult skills for a tech to learn, so don't be discouraged if you have difficulty with this at first
Please clean the tonometer and slit lamp first thing when you get into the room. This will allow for any alcohol residue to dry before you need to take IOP (see below)
Corneal abrasions here are always a risk, but are almost always caused by not drying the alcohol off the tonometer tip well, so be sure to do this first and dry off completely!
Please try sit when checking IOP (if possible due to your height) and try not stand upright! (The providers never stand, so you shouldn't either)
Note:
There are 2 ways to check IOP, such as dialing the tonometer to the expected IOP first, and then touching the cornea.
We like for everyone to learn starting from 0 first, and then adjust to personal preference when you get more comfortable and your skill level grows.
Notice the light blue quarter circles in the middle if the image
We call these "ghost mires' or "mire reflections"
These are a great indicator of any adjustments you need to make before you even make contact with the eye
You want these equal in size like in the image
Set the tonometer to zero. This will give you a more clear image of these ghost mires
While holding the joystick back, move the base closer to the eye. When you get within "eyelash range", look through the optics and move closer.
When you move closer to the eye, these ghost mires will also move closer together
When they are just overlapping like so, turn the dial on the tonometer forward and you will make contact with the cornea as evident by the fluorescent mires (Below)
Fluorescent Mires
This means you are making physical contact with the cornea!
Small corrections are OK while touching the cornea (moving slightly up/down/left/right)
For larger corrections, pull back so you're not touching the cornea, make the correction, and go forward again
Turn the dial on the tonometer forward until the mires are just overlapping as seen
When you get this, you have the correct IOP!
Immediately pull the whole slit lamp back so you are no longer making contact with the cornea
Reset the tonometer dial to Zero, and repeat for OS
Using this method, the ghost mires won't be as clear as on 0 because the prism is moved forward slightly which breaks the line of sight
This is essentially the same as the first method but with minor differences
When you advance towards the cornea, just as you start to see the fluorescent mires, push slightly forward on the joystick so the tonometer tip is more firm on the cornea
From here, adjust the knob as before so the mires are just overlapping and then pull back