Friday, January 20, 2012

What I Do at Work part 2

There are 2 things that make the patient believe that the technician does all the work (and to that I tell them I deserve a raise). The first is the manifest refraction I described in the last post - "which is better 1 or 2?" The second is when I check the pressure in the eyes with a tonometer.
Not me, but you get the idea (source)
To do this I give the patient a drop of flucaine in each eye. It is a bright yellow numbing drop. Ironically, the drops sting when they first go in. I then hold the patient's lids open and  place the tip of the Perkins tonometer on the cornea. When I look through my tool, I am looking for a green line that I will align and use to obtain the measurement.
My View (source)
Can you see the faint green semicircles? Now imagine if the patient is sensitive and is squeezing their eyes shut. To get a good view, one must get up close and personal. Short fingernails and good breath are a must. When I have to give this test to prisoners, I get scared. Usually the patient is unaware that the instrument is touching the eye. Pressures between 10 and 20 are normal. Savvy patients, usually those with glaucoma will be very curious as to knowing their measurement. This method of measurement has replaced the need for the "puff of air" test in our office.

After checking pressure, I will instill the dilating drops. We use two types phenelyephrine 2.5% and tropicamide 1%. Because we usually instill these after the numbing drops, no pain is felt. This is different than when I worked in pediatrics and we just had to tell the kids that it would feel like soap is in their eyes. The dilating drops are important so that the doctor will be able to look into the back of the eye where the nerves and blood vessels are. To look inside, he will need to shine a light in. The dilation drops keeps the muscles of the eye from contracting and gives the doctor a more complete view. The drops can last anywhere from 4 to 24 hours depending on the individual. This will make it especially hard to read and the sunlight will seem very bright. We encourage our patients to bring a driver with them, however, if you've had them before and are comfortable driving then it may not be a problem.

In my next post I'll discuss testing like visual fields, OCTS and pachymetry.

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