Low Vision & Rehabilitation Flashcards
7 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 7 Low Vision & Rehabilitation flashcards as text
Which magnification formula correctly calculates the required add power for a patient with 20/200 acuity who wants to read standard newsprint (20/40 equivalent)?
Answer: Add = (20/200) / (20/40) × 4D = 20D
The required magnification is 200/40 = 5×, and since 1× requires approximately 4D, the needed add is 5 × 4D = 20D.
A patient with central scotoma due to macular degeneration is taught eccentric viewing. The preferred retinal locus (PRL) is most commonly located in which direction relative to the scotoma?
Answer: The PRL location varies by individual and must be determined clinically
The PRL develops spontaneously in a location that varies among individuals, and clinical assessment (e.g., microperimetry or scanning laser ophthalmoscopy) is needed to identify it.
Which illumination strategy is most beneficial for a patient with retinitis pigmentosa (RP) experiencing significant glare sensitivity indoors?
Answer: Use highly directional task lighting aimed at the work surface while reducing ambient light
Directing task lighting onto the work area while keeping ambient lighting lower reduces the glare-contrast problem common in RP patients with rod depletion.
A 68-year-old patient's best-corrected visual acuity is 20/400. When fitting a spectacle-mounted telescope for distance mobility, the clinician should prioritize which consideration?
Answer: Field of view, weight, and cosmetic acceptance in addition to acuity improvement
High-magnification telescopes drastically reduce field of view and are heavier, so functional factors and patient acceptance must be balanced with acuity improvement.
Stand magnifiers are optically designed so that the image they produce is located at which focal distance?
Answer: At infinity, requiring no additional accommodation or add
A stand magnifier places the object at its focal point, producing a virtual image at optical infinity that requires no accommodation (or only the patient's habitual near add) to view.
Which of the following best describes the purpose of a bioptic telescope system for driving?
Answer: To provide a brief spotting system for signs and traffic lights while the carrier lens is used for primary driving
Bioptic telescopes are used intermittently as a spotting device; the driver uses the carrier lens for the majority of visual tasks and dips briefly into the telescope.
During low vision evaluation, a patient achieves better performance on reading tasks with a typoscope. What is the primary optical or perceptual mechanism by which a typoscope aids reading?
Answer: It reduces glare and isolates the line of text to minimize visual crowding
A typoscope is a non-optical black matte card with a window that blocks stray light (reducing glare) and limits the visible text to one line, reducing crowding effects.