Low Vision and Optical Aids Flashcards
7 cards from real COT 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 and Optical Aids flashcards as text
A basic telescopic system used for distance low vision consists of which optical components?
Answer: An objective lens and an ocular (eyepiece) lens
A telescope uses an objective (front) lens to collect and focus light and an ocular (eyepiece) lens through which the patient views the resulting magnified image.
What is the function of a 'reading cap' when added to a distance telescope?
Answer: To convert the telescope for near-vision tasks
A reading cap is a plus lens attached to the objective end of a telescope, changing its focus from distance to near and creating a telemicroscope for close work.
Which electronic magnification device offers adjustable magnification, contrast reversal, and color settings to assist with reading tasks?
Answer: Closed-circuit television (CCTV) / video magnifier
A CCTV or video magnifier uses a camera and monitor to provide variable magnification, polarity reversal, and color adjustments that optical devices cannot offer.
The preferred retinal locus (PRL) is best described as:
Answer: A peripheral retinal area spontaneously adopted for fixation when the fovea is damaged
The PRL is a non-foveal retinal location that a patient with macular disease spontaneously develops as the new fixation point to optimize remaining vision.
Which illumination strategy is most beneficial for low vision patients performing near tasks such as reading?
Answer: High-intensity, directed task lighting positioned near the work surface
High-intensity task lighting directed at the work surface maximizes contrast sensitivity and visual performance for most low vision patients doing near tasks.
Why is contrast sensitivity testing important in a low vision evaluation, even when Snellen acuity appears only mildly reduced?
Answer: It assesses functional vision at various spatial frequencies and may reveal deficits not captured by standard letter acuity
Contrast sensitivity measures detection of luminance differences across spatial frequencies, revealing real-world functional deficits that standard Snellen acuity may not detect.
Which absorptive lens tint is most commonly recommended to reduce photophobia and improve contrast for patients with age-related macular degeneration?
Answer: Yellow or amber-tinted lenses
Yellow and amber tints selectively filter short-wavelength (blue) light that causes intraocular scatter, reducing photophobia and improving contrast sensitivity.