Vision and Ophthalmology Optics and Refraction 3

Question 1

What is the purpose of a lensometer (lensmeter)?

Accepted Answer

Measure the power of a fabricated spectacle lens

Answer

Measure corneal curvature

Answer

Map the visual field

Answer

Measure IOP

Question 2

Irregular astigmatism, unlike regular astigmatism, cannot be fully corrected by:

Accepted Answer

Spectacle lenses with cylindrical correction

Answer

Soft contact lenses

Answer

Rigid gas-permeable contact lenses

Answer

Orthokeratology

Question 3

Snellen visual acuity of 20/40 means the patient can see at 20 feet what a normal eye can see at:

Accepted Answer

40 feet

Answer

10 feet

Answer

20 feet

Answer

80 feet

Question 4

What is the near point of accommodation in a fully accommodating emmetropic eye?

Accepted Answer

Approximately 7–10 cm (varies by age)

Answer

Infinity

Answer

6 meters

Answer

The corneal surface

Question 5

Which test uses polarized filters to measure stereoacuity (depth perception)?

Accepted Answer

Random dot stereotest (e.g., Randot)

Answer

Worth 4-dot test

Answer

Hirschberg test

Answer

Amsler grid

Question 6

Base-out prism correction for esotropia works by:

Accepted Answer

Displacing the image toward the base, reducing the convergence demand

Answer

Increasing the angle of deviation

Answer

Displacing the image toward the apex, requiring inward rotation

Answer

Blocking the deviating eye