A patient is diagnosed with low vision. According to the standard classification, which Best Corrected Visual Acuity (BCVA) range defines this condition?

Appeared in: NORCET 3 - 2022 (Shift-1)

Explanation

Low vision is clinically defined as a best-corrected visual acuity (BCVA) ranging from 20/70 to 20/200 in the better-seeing eye.
This classification is consistent with World Health Organization (WHO) guidelines, which categorize moderate visual impairment as having acuity worse than 6/18 (approx. 20/60) up to 6/60 (approx. 20/200).
This level of vision loss significantly interferes with daily activities and requires the use of visual aids, but it does not meet the U.S. criteria for legal blindness (20/200 or worse).

Option A: This range (20/20 to 20/60) represents normal to near-normal vision (mild visual impairment), not low vision.
Option C: This range (20/400 to no light perception) is classified as severe to profound blindness, which is a more significant level of impairment than low vision.
Option D: A visual acuity of less than 20/500 falls into the category of profound or total blindness, far exceeding the definition of low vision.

Clinical Relevance

Nursing practice connection: Use the key finding related to Classification of visual impairment based on Best Corrected Visual Acuity (BCVA) to guide bedside assessment, documentation, and the next nursing action.
Nurses must accurately assess a patient's level of visual impairment to implement appropriate safety measures, such as ensuring a well-lit, clutter-free environment to prevent falls.
Patient education is a key nursing role, involving teaching the use of assistive devices (magnifiers, large-print materials) and orientation techniques (like the clock method for meals) to enhance independence and quality of life.
What if? If a patient's vision deteriorates to 20/200, they would be classified as legally blind. The nurse's role would then expand to include facilitating referrals for social services and government benefits for which the patient is now eligible.

How to Approach the Question

First, identify the key term in the question: 'low vision'. This is a specific clinical definition you need to recall.
Recognize that visual impairment exists on a spectrum. Mentally arrange the categories from best to worst: Normal -> Mild Impairment -> Low Vision -> Blindness.
Eliminate the options at the extremes. '20/20 to 20/60' includes normal vision, so it's incorrect. '20/400 to no light perception' describes total blindness, which is too severe.
Differentiate between 'low vision' and 'legal blindness'. The threshold for legal blindness in the U.S. is a key benchmark (20/200). Low vision is the category of impairment just before a person is considered legally blind.
Based on this, select the option that falls between mild impairment (ends around 20/60) and legal blindness (starts at 20/200). The range '20/70 to 20/200' fits this definition perfectly.

Concept Tested & Keywords

Concept Tested: Classification of visual impairment based on Best Corrected Visual Acuity (BCVA).
Stem keywords: low vision, Best Corrected Visual Acuity, BCVA, classification
Lead-in keywords: defines this condition

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E6 Nursing Brunner Adult Health 3SA Vol 2 Part 1 p. 88-90

E6 Comprehensive Textbook of Community Health Nursing for BSc Nursing Students Part 2 — Subpart A (pp 1-275 of 550) p. 111-113

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