Diagnostic testing is a critical component of providing quality patient care. A knowledgeable diagnostic technician who can properly operate the equipment can assist the physician in making the correct diagnosis and is an essential part of the ophthalmology team.
We will discuss the Humphrey Visual Field (HVF) in part one of this blog as this is typically the diagnostic test a new technician would be responsible to perform. First, the technician should understand why a visual field test would be ordered and the visual limitations of an individual with a visual field defect, i.e. glaucoma, pituitary adenoma, Plaquenil toxicity, etc. Second, they want to pay special attention to the specific visual field test that was ordered, is it a 24-2, 10-2, ptosis field and should it be preformed SITA Standard, SITA Fast, or some Humphrey’s with a new update have the SITA Faster option. It may be helpful to have a doctor preference sheet posted in the testing room that can easily referenced to if different physicians have different visual field preferences. For example, your glaucoma specialist may want all 24-2’s to be done as SITA Standard versus your general ophthalmologist prefers SITA Fast.
Next, the technician should be aware of how to make adjustments based on the specific patient’s needs, i.e. wheelchair, head positioning, eye patch difficulties, etc. If a patient has a difficult time transferring from a wheelchair and the table can go low enough to accommodate it may be unnecessary to have the patient transfer into a chair for the testing. Ensure the trial lens has the most updated script as the patient may have recently had cataract surgery or a change in from their previous glasses. The technician should monitor for fixation losses during the testing to gently encourage the patient to keep focused on the fixation light. Your physician may want fixation losses to be below a certain number and the test may need to be restarted. As such the technician should not leave the testing room while the visual field test is being performed.
Training on the visual field should include common scenarios that may arise. If the doctor is concerned about an eyelid defect he or she may order the eyelid to be taped during visual field testing, before applying tape ask if the patient has any adhesive allergies. If a pirate patch is difficult for your patient to handle then consider an eye patch with tape or Mask-It patch. The patient may comment that the second eye “looks dimmer” or “blurry” in that case the technician should remind them to keep blinking normally to prevent dryness during the testing and could be due to eye fatigue and strain from the first eye. Encourage the patient to do the best they can and to relax during the test.
As always, remember to explain to each patient what testing is being done and why. This simple step can make a world of difference to your patient. As you are preforming the diagnostic test your role is to guide the patient through the process, don’t forget what may be routine to you is new for them.