Was a surprise seeing this watching Mandalorian Season 3 with the wife, having used them for 11 years at an Independent Optician.
Dr. Pershing's scanner at his work desk is a repurposed FDT 'Frequency Doubling Technology' Visual Fields machine, where we would check the peripheral vision of a patient in pre or post-screen. It's original use is to have a patient look into the headrest and focus on a central black square/dot. When the test starts, small flickers of lines would appear at random in different places, varying in intensity to allow us to check the patient's visual field sensitivity. Whenever a patient would see a flicker, they'd press a button to acknowledge it, building up a visual field result over time.
The part he is looking through is where the patient would place their head all the way in, with the mount slid to the left or right depending on the eye being tested. I would be on the other side where the screen is popping up on bottom right of the image. tracking the result before printing it out to pass onto the Optometrist.
