CO CO Optical Instruments & Diagnostic Equipment 2 — Questions and Answers
Question 1: The Bagolini striated lens test is used to evaluate which aspect of binocular vision?
- Distance stereoacuity
- Retinal correspondence and suppression (Correct answer)
- Accommodative convergence ratio
- Intraocular pressure
Correct answer: Retinal correspondence and suppression
Bagolini striated lenses test retinal correspondence and suppression under near-natural viewing conditions by creating streak images from a point source.
Question 2: A keratometer (ophthalmometer) is used to measure which ocular parameter?
- Axial length
- Corneal curvature/power (Correct answer)
- Pupil diameter
- Anterior chamber depth
Correct answer: Corneal curvature/power
A keratometer measures the curvature of the anterior corneal surface, which is essential for contact lens fitting and detecting astigmatism.
Question 3: When performing retinoscopy, a 'with' motion of the reflex indicates which refractive state?
- Myopia beyond the far point
- Hyperopia or myopia less than working distance (Correct answer)
- Emmetropia exactly
- Astigmatism only
Correct answer: Hyperopia or myopia less than working distance
A 'with' motion in retinoscopy occurs when the patient's far point is beyond the examiner, indicating hyperopia or myopia less than the working distance correction.
Question 4: The Hess screen test and the Lee screen test both map the positions of gaze to identify which condition?
- Accommodative spasm
- Extraocular muscle paresis or restriction (Correct answer)
- Pupillary light reflex defects
- Convergence insufficiency
Correct answer: Extraocular muscle paresis or restriction
Hess and Lee screen tests plot ocular motility in all nine diagnostic positions of gaze to identify and localize paretic or restricted extraocular muscles.
Question 5: When calibrating a prism cover test measurement, what does the endpoint (neutralization point) indicate?
- Maximum suppression
- Equal and opposite movement of both eyes under cover
- No refixation movement when cover is moved (Correct answer)
- Full accommodation is exerted
Correct answer: No refixation movement when cover is moved
Neutralization is reached when no refixation movement is observed as the cover is alternated, meaning the prism has fully corrected the measured deviation.
Question 6: The 4-prism diopter base-out test is used to detect which condition?
- Convergence excess
- Central suppression scotoma in the fovea (Correct answer)
- Accommodative esotropia
- Superior oblique palsy
Correct answer: Central suppression scotoma in the fovea
The 4Δ base-out test detects a small central suppression scotoma: a normal response shows both eyes moving, while suppression causes only the fellow eye to move.
CO CO Optical Instruments & Diagnostic Equipment 2
The Bagolini striated lens test is used to evaluate which aspect of binocular vision?