Secondary Prevention
This scenario represents secondary prevention (Answer C), as it involves early detection of an existing condition (refractive error causing low vision) through screening, followed by intervention to prevent progression to more severe visual impairment.
Understanding the Levels of Prevention Framework
The classification of prevention levels follows a clear hierarchy based on the timing and nature of the intervention 1:
- Primordial prevention targets underlying risk factors before disease development in entire populations
- Primary prevention prevents disease occurrence in at-risk individuals before any pathology exists
- Secondary prevention detects and treats early, asymptomatic disease to prevent progression
- Tertiary prevention manages established disease to prevent complications and restore function
Why This is Secondary Prevention
The key distinguishing feature is that the student already has an existing condition—refractive error causing measurable low vision—that was detected through screening before it caused more severe functional impairment 2, 3.
Critical Elements Present:
- Early detection through screening: The school health program identified low vision before the student may have sought care independently 2
- Existing pathology: A refractive error was confirmed on examination, representing an established optical abnormality 1
- Intervention to prevent progression: Corrective glasses were prescribed to prevent the development of more severe visual impairment, potential amblyopia, or educational difficulties 4, 3
Why Other Options Are Incorrect
Primary prevention would involve interventions before any refractive error develops, such as outdoor time to prevent myopia onset, which is not applicable here since the refractive error already exists 1.
Tertiary prevention would address complications of untreated refractive error, such as treating established amblyopia or managing educational deficits that have already occurred from prolonged uncorrected vision 1.
Primordial prevention would target population-level risk factors before any individual develops risk for refractive errors, which is not relevant to this clinical scenario.
Clinical Context and Significance
School-based vision screening programs identify substantial numbers of students with refractive errors, with over 35% of students who fail screening having clinically significant refractive error requiring correction 2. Uncorrected refractive errors affect more than 2.3 billion people globally, with 670 million considered visually impaired due to lack of access to corrective treatment 3.
Common Pitfall to Avoid:
Do not confuse the provision of corrective glasses with tertiary prevention simply because treatment is being provided. The timing and purpose of the intervention determine the prevention level—here, the goal is preventing progression of visual impairment and its educational consequences, not managing established complications 1, 4.
The American Academy of Ophthalmology emphasizes that provision of appropriate spectacles is one of the most cost-effective strategies to improve vision and should be considered the first-line intervention for refractive errors 1. In children, early identification and proper correction prevents amblyopia development and ensures normal visual development 4.