Myopia is corrected by?

AIIMS Nagpur NO - 2018

Medical Surgical Nursing

Easy

Appeared in: AIIMS Nagpur NO - 2018

Explanation

Myopia, or nearsightedness, is a refractive error where the eye focuses images in front of the retina instead of on the retina.
This causes distant objects to appear blurry, while close objects can be seen clearly.
A biconcave lens is a diverging lens that spreads out light rays before they reach the eye's lens.
This divergence moves the focal point backward, allowing the image to be focused correctly on the retina, thus correcting the vision.

Option A: A bifocal lens has two different prescriptions in one lens and is primarily used to correct presbyopia, the age-related difficulty in near vision.
Option B: A biconvex lens is a converging lens that increases refractive power. It would worsen myopia by causing light to focus even further in front of the retina.
Option C: A cylindrical lens corrects for uneven curvature of the cornea or lens, which is characteristic of astigmatism, not myopia.

Visual 1: Diagram - A comparative diagram showing the light pathways in a normal (emmetropic) eye, a myopic eye, and a hyperopic eye, both with and without their respective corrective lenses (concave for myopia, convex for hyperopia). This helps visualize the core concept.
Visual 2: Infographic - An infographic illustrating the four main types of refractive errors (myopia, hyperopia, astigmatism, presbyopia) with icons representing the shape of the eyeball, the focal point of light, and the type of corrective lens used for each.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Correction of Myopia as background academic context rather than a clinical decision trigger.
Nurses play a key role in vision screening programs, especially in schools, to detect refractive errors like myopia early. Early detection and correction are vital to prevent learning difficulties and amblyopia (lazy eye).
Patient education is a core nursing responsibility. A nurse should be able to explain to a patient or their family what myopia is and why a specific type of lens (biconcave) is prescribed.
A nurse should recognize symptoms of uncorrected myopia, such as squinting, headaches, eye strain, or holding reading materials very close to the face, and recommend an ophthalmologic evaluation.

How to Approach the Question

First, understand the question. It asks for the specific type of lens used to correct myopia.
Recall the definition of myopia: It is nearsightedness, where light focuses in front of the retina.
Consider the physics of lenses. To move the focal point backward onto the retina, you need a lens that diverges or spreads out light rays.
Evaluate the options based on this principle. A concave (biconcave) lens is a diverging lens.
Eliminate the other options by recalling their primary uses: Biconvex lenses are converging and correct hyperopia; cylindrical lenses correct astigmatism; bifocal lenses correct presbyopia.
Confirm your choice: Myopia requires a diverging lens, which is a biconcave lens.

Concept Tested & Keywords

QV-oxPac-bSGMnsof-jeLH