CO CO Optical Instruments & Diagnostic Equipment 1 — Questions and Answers
Question 1: Which instrument is primarily used to measure the angle of deviation in strabismus by projecting a light onto each cornea?
- Hirschberg light reflex test
- Krimsky test (Correct answer)
- Prism cover test
- Worth 4-dot test
Correct answer: Krimsky test
The Krimsky test uses a prism placed before one eye while observing corneal light reflexes to measure the angle of strabismic deviation.
Question 2: A synoptophore (amblyoscope) is BEST used to assess which of the following?
- Intraocular pressure
- Corneal curvature
- Binocular vision and fusion (Correct answer)
- Retinal thickness
Correct answer: Binocular vision and fusion
The synoptophore is a major amblyoscope used to assess, measure, and treat binocular vision disorders including fusion and stereopsis.
Question 3: The Worth 4-dot test uses which colors to assess binocular fusion?
- Red, green, blue, white
- Red, green, and white (Correct answer)
- Blue, yellow, and red
- Green, white, and yellow
Correct answer: Red, green, and white
The Worth 4-dot test uses two green dots, one red dot, and one white dot, viewed through red-green glasses to assess binocular fusion.
Question 4: When using a prism bar to measure a horizontal deviation, the prism base direction should be oriented in which direction to neutralize an esotropia?
- Base-up
- Base-down
- Base-out (Correct answer)
- Base-in
Correct answer: Base-out
Base-out prisms neutralize esotropia by shifting the image toward the deviated eye, allowing the cover-uncover test to show neutralization.
Question 5: The Maddox rod test is primarily used to measure which type of deviation?
- Tropias only
- Phorias and small tropias (Correct answer)
- Cyclodeviations
- Vertical deviations only
Correct answer: Phorias and small tropias
The Maddox rod dissociates the eyes and measures the full extent of a phoria or small tropia by converting a point of light into a streak.
Question 6: Which instrument measures stereoacuity using random dot patterns without monocular cues?
- Titmus fly test
- TNO test (Correct answer)
- Lang stereotest
- Frisby test
Correct answer: TNO test
The TNO test uses random-dot anaglyphic plates that eliminate all monocular cues, making it a true test of stereoscopic depth perception.
CO CO Optical Instruments & Diagnostic Equipment 1
Which instrument is primarily used to measure the angle of deviation in strabismus by projecting a light onto each cornea?