Which of the following statements is NOT correct about myopia?
In the affected eye, the image of a distant object is formed beyond the retina
Understanding Myopia and Vision Correction
This question asks us to identify the statement that is NOT correct about myopia. Myopia is a common vision condition that affects how people see objects at different distances. Let's examine each statement to determine its accuracy regarding myopia.
Analyzing Statements about Myopia
Let's break down each given statement about myopia:
- Statement 1: The vision may be corrected with the help of concave lens.
This statement is correct. Myopia occurs because the eye focuses light in front of the retina instead of directly on it. A concave lens diverges (spreads out) the incoming light rays slightly before they enter the eye. This divergence ensures that the light rays focus correctly on the retina, correcting the blurry vision for distant objects caused by myopia.
- Statement 2: It is also known as near sightedness.
This statement is also correct. Myopia is universally known as near-sightedness. This term reflects the fact that people with myopia can typically see near objects clearly, but distant objects appear blurry.
- Statement 3: In the affected eye, the image of a distant object is formed beyond the retina.
This statement is incorrect regarding myopia. In an eye affected by myopia, the eyeball is often slightly too long, or the cornea is too curved. This causes light from distant objects to converge and form an image in front of the retina, not beyond it. The image formed on the retina itself is therefore out of focus, resulting in blurry distant vision.
- Statement 4: The person affected by it cannot see beyond few metres.
This statement is generally correct. Myopia causes difficulty in seeing distant objects clearly. Depending on the severity of the myopia, the clear vision might be limited to only a few meters or even less. Objects further away appear increasingly blurry.
Identifying the Incorrect Statement about Myopia
Based on our analysis, Statement 3 is the one that incorrectly describes what happens in an eye with myopia. In myopia, the image of a distant object is formed in front of the retina, not beyond it.
Therefore, the statement that is NOT correct about myopia is: In the affected eye, the image of a distant object is formed beyond the retina.
| Statement about Myopia | Correct/Incorrect? | Explanation |
|---|---|---|
| Vision corrected with concave lens | Correct | Concave lenses diverge light to focus image on retina. |
| Also known as near sightedness | Correct | Common term for myopia. |
| Image of distant object formed beyond retina | Incorrect | Image is formed in front of the retina in myopia. |
| Cannot see beyond few metres | Correct | Characteristic symptom of myopia; distant vision is blurry. |
Revision Table: Key Concepts of Myopia
| Concept | Description in Myopia |
|---|---|
| Alternative Name | Near-sightedness |
| Vision Problem | Difficulty seeing distant objects clearly |
| Cause (Common) | Eyeball too long or cornea too curved |
| Image Formation (Distant Object) | Image forms in front of the retina |
| Correction Method | Concave (diverging) lenses |
Additional Information on Vision Defects and Correction
Besides myopia, other common refractive errors include hyperopia (far-sightedness), presbyopia, and astigmatism.
- Hyperopia: The eye focuses light behind the retina. Corrected with convex (converging) lenses. People with hyperopia see distant objects better than near objects.
- Presbyopia: A age-related condition where the eye's lens loses flexibility, making it difficult to focus on near objects. Often corrected with bifocal or progressive lenses.
- Astigmatism: Caused by an irregularly shaped cornea or lens, leading to blurred or distorted vision at all distances. Corrected with cylindrical lenses or toric contact lenses.
Refractive errors like myopia can be corrected using corrective lenses (glasses or contact lenses) or refractive surgery (like LASIK).
Important Questions from Reflection and Refraction
Upon sudden exposure to bright light, which muscular structure within the eye actively constricts to limit the amount of light entering the posterior chamber and safeguard the retina?
A ray of light is incident from air on a glass surface. If the reflected and refracted rays are perpendicular to each other when the angle of incidence is $60^\circ$, what is the critical angle for total internal reflection at the glass-air interface?
The ability of the eye to focus on distant objects as well as nearby objects is called
Normal ray, incident ray and reflected ray lie in the-
The image formed on the retina of the human eye is-
