Myopia can be corrected by using which lens?

RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

Applied Physiology

Easy

Appeared in: RUHS, Jaipur, M.Sc Nursing Entrance Exam-2015

Explanation

Myopia, or nearsightedness, is a condition where the eye focuses images of distant objects in front of the retina, rather than on the retina itself.
This is typically due to an eyeball that is too long or a lens system with excessive refractive power.
A concave lens is a diverging lens, which means it spreads out light rays before they reach the eye's lens.
This divergence effectively moves the focal point backward, allowing the image to be focused correctly on the retina, thus correcting the blurry distant vision.

Option A: A convex lens is a converging lens that brings light rays to a focus more quickly. It would worsen myopia by moving the focal point even further in front of the retina.
Option B: A cylindrical lens corrects for uneven focusing in different planes, which is not the primary issue in simple myopia.
Option D: A plain lens has no refractive power and does not bend light. It is essentially a flat piece of glass or plastic and cannot correct any vision defects.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Correction of Refractive Errors as background academic context rather than a clinical decision trigger.
Nurses are often involved in health screenings, including basic vision tests. Understanding the principles of refractive errors helps in identifying potential vision problems in patients and providing accurate health education.
Patient education is key. A nurse can explain to a patient or their family why a specific type of lens is prescribed, improving adherence and understanding of their condition.
What if? If a patient with high myopia suddenly stops wearing their corrective lenses, they are at a higher risk for falls and accidents due to poor distance vision. Nurses should assess for safety, especially in unfamiliar environments like a hospital.

How to Approach the Question

First, identify the key term in the question: 'Myopia'.
Recall the definition of myopia. It is also known as nearsightedness, meaning the person can see near objects clearly, but distant objects are blurry.
Understand the underlying optical problem: in myopia, the light focuses in front of the retina.
Think about the goal of correction: to move the focal point backward onto the retina.
Consider the function of different lenses. A lens that spreads light out (diverges) will move the focal point backward. A lens that brings light together (converges) will move it forward.
Match the function to the lens type: Concave lenses diverge light, and convex lenses converge light.

Concept Tested & Keywords

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