BRS Low Vision Aids & Devices 2 — Questions and Answers
Question 1: A patient with a central scotoma reports difficulty reading despite using a stand magnifier. Which adaptation is MOST likely to improve their reading performance?
- Switch to a hand magnifier with higher power
- Train eccentric viewing using preferred retinal locus (Correct answer)
- Prescribe prismatic lenses to shift the image
- Recommend a CCTV with standard magnification
Correct answer: Train eccentric viewing using preferred retinal locus
Training the patient to use their preferred retinal locus (PRL) through eccentric viewing allows them to bypass the central scotoma for more effective reading.
Question 2: Which type of low vision device provides the widest field of view for a patient needing distance magnification?
- Galilean telescope (Correct answer)
- Keplerian telescope
- Bioptic telescope
- Fresnel prism lens
Correct answer: Galilean telescope
Galilean telescopes provide a wider field of view compared to Keplerian telescopes, making them preferable when field of view is a priority over image quality.
Question 3: A patient uses a 4× stand magnifier. What is the approximate equivalent viewing distance (EVD) for this device?
- 6.25 cm (Correct answer)
- 10 cm
- 25 cm
- 40 cm
Correct answer: 6.25 cm
EVD = 100 / (magnification × 4) = 100/16 = 6.25 cm for a 4× stand magnifier using the standard formula.
Question 4: When fitting a patient with absorptive lenses for photophobia, the specialist should prioritize which characteristic?
- Lens weight and frame style
- Spectral transmission and UV protection (Correct answer)
- Anti-reflective coating only
- Lens thickness for cosmetic appearance
Correct answer: Spectral transmission and UV protection
Absorptive lenses for photophobia must be evaluated by their spectral transmission curve and UV-blocking properties to reduce glare and protect the retina.
Question 5: Which illumination strategy is MOST effective for a patient with retinitis pigmentosa who experiences difficulty in low-light environments?
- Reduce ambient lighting to avoid glare
- Provide high-intensity task lighting aimed directly at work surface (Correct answer)
- Use diffuse overhead fluorescent lighting only
- Recommend dim red-spectrum lighting
Correct answer: Provide high-intensity task lighting aimed directly at work surface
Patients with RP have reduced rod function and benefit most from high-intensity, well-directed task lighting to maximize remaining cone function.
Question 6: A patient asks about the difference between an optical character recognition (OCR) system and a CCTV. Which statement BEST distinguishes them?
- CCTVs convert text to speech while OCR systems only enlarge images
- OCR systems convert printed text to digital text or synthesized speech; CCTVs magnify images visually (Correct answer)
- OCR systems require internet connectivity while CCTVs do not
- CCTVs are portable while OCR systems are only desktop-based
Correct answer: OCR systems convert printed text to digital text or synthesized speech; CCTVs magnify images visually
OCR technology reads and converts printed text into digital or audio output, while CCTVs (video magnifiers) electronically enlarge and display images on a screen.
Question 7: Which monocular telescope design is typically recommended for a patient who needs to read menus and signs at intermediate distances (1–3 meters)?
- 2× Galilean distance telescope
- Reading cap added to a distance telescope (Correct answer)
- Full-field microscopic spectacle
- Dome magnifier
Correct answer: Reading cap added to a distance telescope
Adding a reading cap to a distance telescope shortens its focal point to intermediate distances, making it suitable for reading menus, signs, and price tags.
BRS Low Vision Aids & Devices 2
A patient with a central scotoma reports difficulty reading despite using a stand magnifier.
Which adaptation is MOST likely to improve their reading performance?