Myopia can be corrected with the help of?

ESIC Nursing Officer 2016 (Shift -2)

Medical Surgical Nursing

Easy

Appeared in: ESIC Nursing Officer 2016 (Shift -2)

Explanation

Myopia, or nearsightedness, is a refractive error where the eye focuses images from distant objects in front of the retina, rather than directly on it.
This misalignment causes distant objects to appear blurry, while close objects remain clear.
A concave lens is a diverging lens, meaning it spreads out light rays before they reach the eye's natural lens.
This divergence effectively moves the overall focal point backward, allowing it to land precisely on the retina, which corrects the vision and results in a clear image.

Option A: Convex lenses are converging lenses that increase the refractive power. They are used to correct hypermetropia (farsightedness), where light focuses behind the retina. Using a convex lens for myopia would worsen the condition.
Option C: Cylindrical lenses have different refractive powers in different meridians and are specifically used to correct astigmatism, which is caused by an irregular curvature of the cornea or lens.
Option D: This is not a standard ophthalmological term for correcting refractive errors. While prisms can be incorporated into lenses at an angle to correct for eye alignment issues (like strabismus or diplopia), they do not correct the fundamental focusing error of myopia.

Visual 1: Diagram illustrating the light path in a myopic eye (focusing in front of the retina) and how a concave lens diverges the light to correct the focus onto the retina.
Visual 2: Comparison diagram showing the shape of a concave (thinner in the middle) vs. a convex (thicker in the middle) lens and their different effects on parallel light rays.
Visual 3: Flowchart showing the diagnosis of refractive errors: Visual acuity test -> Phoropter/Retinoscopy -> Identification of Myopia/Hypermetropia/Astigmatism -> Prescription of appropriate lens.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Refractive Errors and Corrective Lenses as background academic context rather than a clinical decision trigger.
Nurses, especially in school health and community settings, are often involved in initial vision screenings using Snellen charts. Identifying children who have difficulty reading distant letters is a key step in detecting potential myopia.
Patient education is a vital nursing role. A nurse can explain to a patient or parents what myopia is, the importance of wearing prescribed glasses to prevent eye strain and headaches, and the need for regular follow-up with an optometrist or ophthalmologist.
What if? If a patient with myopia is accidentally given glasses with convex lenses, their distance vision will become significantly more blurred. This is because the convex lens will converge light even more strongly, moving the focal point further in front of the retina.

How to Approach the Question

First, identify the key term in the question: 'Myopia'.
Recall the definition of myopia. It is 'nearsightedness', meaning you can see near objects clearly, but distant objects are blurry.
Visualize or recall the pathophysiology: In myopia, the light focuses in front of the retina.
Determine the goal of correction: A lens is needed to move the focal point backward onto the retina.
Analyze the function of the lens options. A concave lens diverges (spreads out) light, which will move the focal point back. A convex lens converges (brings together) light, which would move the focal point further forward.
Based on this, select the concave lens as the correct option for correcting myopia. Eliminate other options based on their specific uses (convex for hypermetropia, cylindrical for astigmatism).

Concept Tested & Keywords

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