FREE CPO Visual Field Testing (Perimetry) Questions and Answers

Question 1

What is the primary purpose of visual field testing (perimetry)?

Accepted Answer

To map a patient's peripheral and central vision

Answer

Perimetry is a diagnostic test that systematically maps the full extent of a patient's vision, including central and peripheral fields. It is crucial for detecting, diagnosing, and monitoring diseases that affect the optic nerve and visual pathways, such as glaucoma, strokes, and brain tumors.

Question 2

During automated perimetry, what is the most common method the machine uses to ensure the patient is maintaining steady fixation?

Accepted Answer

Presenting stimuli in the physiological blind spot

Answer

The perimeter periodically projects a light stimulus into the location of the patient's physiological blind spot, which corresponds to the optic nerve head. If the patient sees and responds to this stimulus, it indicates they have moved their eye and are no longer fixating on the central target. This is known as the Heijl-Krakau method.

Question 3

A visual field test where the stimulus light is stationary but varies in brightness to find the dimmest light a patient can see at each location is known as:

Accepted Answer

Static perimetry

Answer

Static automated perimetry is the most common type of visual field testing today. It involves presenting light stimuli of varying intensities at fixed locations throughout the visual field to determine the threshold of vision at each point. Kinetic perimetry, in contrast, uses a moving stimulus of a fixed brightness.

Question 4

Which of the following visual field defects is most characteristically associated with early to moderate glaucoma?

Accepted Answer

Arcuate scotoma

Answer

Glaucoma typically damages the retinal nerve fibers that arch from the optic nerve superiorly and inferiorly around the macula. This damage results in an arc-shaped (arcuate) scotoma, or blind spot, in the visual field that respects the horizontal midline.

Question 5

What is the most critical instruction to give a patient before starting an automated visual field test?

Accepted Answer

'Press the button for every light you see, no matter how dim, while always looking at the central light.'

Answer

Maintaining steady fixation on the central target is paramount for an accurate and reliable visual field test. If the patient looks around for the lights, the test will not be mapping their peripheral vision correctly, rendering the results invalid. Blinking is normal and encouraged to keep the eye moist.

(CPO) Certified Paraoptometric Practice Test

(CPO) Certified Paraoptometric Practice Test

FREE CPO Visual Field Testing (Perimetry) Questions and Answers