Optics
Does short-sightedness (myopia) or long-sightedness (hypermetropia) imply necessarily that the eye has partially lost its ability of accommodation? If not, what might cause these defects of vision?
A defective eye cannot see close objects clearly because their image is formed:
A defective eye cannot see close objects clearly because there image is formed beyond retina. This defect as known as farsightedness. Here rays from near object could not be converged at the retina due to focal length of the eye lens could not be decreased, so ,image is formed beyond retina.
Does short-sightedness (myopia) or long-sightedness (hypermetropia) imply necessarily that the eye has partially lost its ability of accommodation? If not, what might cause these defects of vision?
Identify the wrong description of the given figures.
For the myopic eye, the defect is cured by
Myopia is due to
Match the list I with the List II for the combination shown Presbiopia Sphero-cylindrical lens Hypermetropia Convex lens of proper power may be used close to the eye Astigmatism Concave lens of suitable focal length Myopia Bifocal lens of suitable focal length
The hyper-metropia is a
To remove myopia ( short sightedness ) a lens of power $$0.66\ D$$ is required. The distant point of the eye is approximately
A person is suffering from 'presbyopia' ( myopia and hyper metropia both defects ) should use
A student sitting at the back of the classroom cannot read clearly the letters written on the blackboard. What advice will a doctor give to her? Draw ray diagram for the correction of this defect.
When do we consider a person to be myopic or hypermetropic? Explain using diagrams how the defects associated with myopic and hypermetropic eye can be corrected?