The Chin & Head Rest
One of the most important parts of the Humphrey Visual Field test is positioning the patient correctly onto the chin rest and head rest. That may sound easy, but it’s probably the hardest part of the test. Before I have the patient settle into the chin rest, I move the machine to about his/her height by eyeballing (lol) it. Then, I have them settle in and I make smaller adjustments so that he/she is comfortable and that the eye is lined up correctly. I always ask, “Is this a comfortable height for you?” For the most part, a majority of them respond with yes. However, during the test, the patient moves away from either the chin or head rest. This is the most annoying part. The patient is probably not intentionally trying to move away, but when he/she does, this causes the machine to beep like crazy.
If they are not right on the chin or head rest, the test may become unreliable. The visual field is pretty sensitive, so try to get the patient positioned in a way where it is hard for them to move around. You don’t want to trap them inside of the chin and head rest (because that sounds insensitive) but you want to keep them as steady as possible.
“DON’T MOVE YOUR EYE!”
The whole point behind the Humphrey Visual Field is to evaluate the patient’s peripheral vision. The test begs the question, “What can the patient see peripherally?” Like I said on the ‘Humphrey Visual Field & Fun’ page, the patient has to focus on the yellow light while the lights flash. I emphasize to all the patients that they cannot follow the flashing lights. However, they always seem to move their eye! I get it, it’s hard not to follow the flashing lights. When I begin to see the patient’s eye following the lights, I immediately tell them to not follow the flashes and focus on the yellow light. Nevertheless, there are those frustrating patients who will not listen to you no matter how often you tell them. After telling them a numerous amount of times to stay focused on the yellow light, I will write down on the patient’s chart that he/she was not following instructions which could have impacted the results of the test.
The simulation that you did on the ‘Humphrey Visual Field & Fun’ page was not even a fraction of how long the test is. The test takes about 3-6 minutes each eye. This allows for the machine to have a comprehensive understanding of the patient’s peripheral vision abilities. The length of the test is the worst part about it. Whenever I bring a patient into the room, they take one look at the machine and want to walk out of the room. Patients will always complain about how the test is “too long” and they “hate it so much.” I try to sympathize with them. Some patients have refused to take the test in the past just because of how long it is. Believe me, I get it. However, if you want a comprehensive glaucoma evaluation, you need to have a visual field. They eventually drop the act and get mentally prepared for the next 6-10 minutes.