AOC AOC Visual Optics and Refraction Concepts 2 — Questions and Answers
Question 1: Presbyopia is caused by which age-related change?
- Increased corneal curvature
- Decreased elasticity of the crystalline lens (Correct answer)
- Increased axial length of the eye
- Corneal clouding
Correct answer: Decreased elasticity of the crystalline lens
Presbyopia results from the gradual hardening and loss of elasticity of the crystalline lens, reducing the eye's ability to accommodate for near vision.
Question 2: Which term describes the ability of the eye to change focus from distance to near objects?
- Convergence
- Accommodation (Correct answer)
- Fusion
- Vergence
Correct answer: Accommodation
Accommodation is the dynamic change in the optical power of the crystalline lens to maintain a clear image at varying distances.
Question 3: In retinoscopy, when the streak reflex moves in the same direction as the retinoscope streak, this is called:
- Against motion
- With motion (Correct answer)
- Neutral motion
- Scissor reflex
Correct answer: With motion
With-motion in retinoscopy indicates that the eye is beyond the working distance or has hyperopia, meaning plus lenses are needed to neutralize.
Question 4: The lensometer (vertometer/lensmeter) is used to measure:
- Corneal curvature
- Intraocular pressure
- The power of a spectacle or contact lens (Correct answer)
- Pupillary distance
Correct answer: The power of a spectacle or contact lens
The lensometer measures the sphere, cylinder, axis, and prism content of an existing spectacle or contact lens.
Question 5: A prism diopter is defined as a deflection of light by how many centimeters at 1 meter?
- 0.5 cm
- 1 cm (Correct answer)
- 2 cm
- 5 cm
Correct answer: 1 cm
One prism diopter deflects a ray of light 1 centimeter at a distance of 1 meter from the prism.
Question 6: Which term describes the condition where the eyes require different amounts of prism correction for binocular alignment at near versus distance?
- Aniseikonia
- Vergence imbalance
- Anisophoria (Correct answer)
- Fusional vergence
Correct answer: Anisophoria
Anisophoria is the difference in phoria measurement (heterophoria) between distance and near gaze, indicating an unequal vergence demand at the two distances.
AOC AOC Visual Optics and Refraction Concepts 2
Presbyopia is caused by which age-related change?