BRS Low Vision Aids & Devices 5 — Questions and Answers
Question 1: A patient with 5° of remaining visual field (tunnel vision) is seeking a device to improve mobility awareness. Which optical strategy is MOST appropriate?
- High-plus spectacle magnifier
- Reverse telescope (minifier) to condense a wide field into the remaining vision (Correct answer)
- High-powered hand magnifier for scanning
- Bioptic telescope for distance acuity
Correct answer: Reverse telescope (minifier) to condense a wide field into the remaining vision
A reverse telescope (minifier) reduces image size but expands the effective field of view, helping patients with severe field constriction perceive more of their environment.
Question 2: According to low vision practice standards, what is the MINIMUM print size that is considered functional for independent reading?
- 1M (approximately 20/100 print equivalent at 1 meter) (Correct answer)
- 2M (approximately 20/200 print equivalent at 1 meter)
- 0.5M (approximately 20/50 print equivalent at 1 meter)
- 4M (approximately 20/400 print equivalent at 1 meter)
Correct answer: 1M (approximately 20/100 print equivalent at 1 meter)
1M print size (equivalent to approximately 20/100 at 1 meter) is commonly cited as the threshold for functional independent reading in low vision standards.
Question 3: Which factor MOST influences the choice between a monocular and binocular telescope for a low vision patient?
- The patient's cosmetic preference exclusively
- The degree of interocular acuity difference and binocular suppression potential (Correct answer)
- The cost difference between the two systems
- The availability of replacement parts
Correct answer: The degree of interocular acuity difference and binocular suppression potential
Significant interocular acuity asymmetry or suppression risk makes binocular telescopes impractical, favoring the monocular design for the better-seeing eye.
Question 4: A patient with diabetic macular edema and fluctuating vision complains that their prescribed magnifier sometimes seems too weak and other times adequate. The BEST advice for the BRS to give is:
- Prescribe the maximum available magnification to always be sufficient
- Recommend flexible electronic magnification that can be adjusted day-to-day (Correct answer)
- Switch to a fixed optical device with the average required power
- Advise the patient to wait until vision stabilizes before using any device
Correct answer: Recommend flexible electronic magnification that can be adjusted day-to-day
Electronic magnifiers allow real-time magnification adjustment, making them ideal for patients with fluctuating vision who need different levels of magnification on different days.
Question 5: What is the primary role of anti-reflection (AR) coating on low vision spectacle lenses?
- To increase the magnification of the lens
- To reduce internal lens reflections that decrease contrast and increase glare (Correct answer)
- To protect the lens from ultraviolet radiation
- To make the lens thinner and lighter for cosmetic purposes
Correct answer: To reduce internal lens reflections that decrease contrast and increase glare
AR coating eliminates internal surface reflections within the lens, which significantly improves contrast sensitivity and reduces distracting glare for low vision patients.
Question 6: A patient asks whether a closed-circuit television (CCTV) or an optical magnifier would provide better contrast sensitivity for reading. The correct answer is:
- Optical magnifiers always provide superior contrast
- CCTVs generally offer superior contrast control because contrast can be electronically enhanced (Correct answer)
- Both devices provide identical contrast at equivalent magnification
- CCTVs reduce contrast due to electronic processing artifacts
Correct answer: CCTVs generally offer superior contrast control because contrast can be electronically enhanced
CCTVs allow electronic manipulation of contrast, brightness, and polarity, enabling contrast enhancement beyond what any optical device can achieve.
Question 7: Which near low vision device is MOST appropriate for a patient who needs high magnification (10×+) but has limited hand steadiness due to essential tremor?
- Hand magnifier at 10×
- Stand magnifier resting directly on the reading material (Correct answer)
- Spectacle-mounted microscope at 10×
- Portable video magnifier held in the hand
Correct answer: Stand magnifier resting directly on the reading material
A stand magnifier sits directly on the page, maintaining a fixed focal distance regardless of hand tremor, making it ideal for patients with motor control limitations.
BRS Low Vision Aids & Devices 5
A patient with 5° of remaining visual field (tunnel vision) is seeking a device to improve mobility awareness.
Which optical strategy is MOST appropriate?