Refraction & Visual Acuity Flashcards
6 cards from real ABO practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 6 Refraction & Visual Acuity flashcards as text
What is the term for the condition where one eye has a significantly different refractive error than the other?
Answer: Anisometropia
Anisometropia is a condition where there is a significant difference in refractive error between the two eyes, which can lead to amblyopia if uncorrected.
Which type of lens is used to correct presbyopia?
Answer: Convex (plus) lens for near addition
Presbyopia is corrected with a plus (convex) add power for near vision, compensating for the loss of accommodation with age.
A patient's vertex distance changes from 12mm to 14mm. How does this affect the effective power of a minus lens?
Answer: The effective power decreases
Moving a minus lens farther from the eye (increasing vertex distance) decreases its effective power at the corneal plane.
What is the typical working distance used for near visual acuity testing?
Answer: 40 cm (16 inches)
The standard near testing distance is 40 cm (16 inches), which corresponds to a 2.50 D accommodative demand.
In retinoscopy, a 'with' motion of the reflex indicates what type of refractive error?
Answer: Hyperopia or insufficient minus correction
A 'with' motion during retinoscopy indicates that the eye is hyperopic or has insufficient minus power, requiring additional plus power to reach neutralization.
What does the term 'emmetropia' describe?
Answer: An eye with no refractive error
Emmetropia describes the ideal refractive state where parallel light rays focus precisely on the retina without any corrective lens.