Eye Defects
MYPOPIA
Myopia is also known as near- sightedness. A person with myopia can see nearby objects clearly but cannot see distant distinctly. A erson with this defect has tje far point nearer than infinity. Such a person may see clearly upto a distance of few metres. In a myopic eye , the image formed in front of the retina and not on at the retina itself. This defect may arise due to excessive curvature of the eye lens or elongation of the eyeball.
Hypermetropia
Hypermetropia is also known as far- sightness. A person with hypermetopia can see distant objects clearly but cannot see nearby objectsobjects distinctly. The ner point for the person is farther away from the normal near point (25cm) . Such a person has to keep a reading material much beyond 25 cm from the eyefor a comfortable reading. This is because the image in formed behind the retina. This defect arises because the eyebll has become too small.
MYPOPIA
Myopia is also known as near- sightedness. A person with myopia can see nearby objects clearly but cannot see distant distinctly. A erson with this defect has tje far point nearer than infinity. Such a person may see clearly upto a distance of few metres. In a myopic eye , the image formed in front of the retina and not on at the retina itself. This defect may arise due to excessive curvature of the eye lens or elongation of the eyeball.
Hypermetropia is also known as far- sightness. A person with hypermetopia can see distant objects clearly but cannot see nearby objectsobjects distinctly. The ner point for the person is farther away from the normal near point (25cm) . Such a person has to keep a reading material much beyond 25 cm from the eyefor a comfortable reading. This is because the image in formed behind the retina. This defect arises because the eyebll has become too small.
Presbypoia
The power of accommodation of the eye usually decreases with ageing. For the most people ,the near point gradually recedes away. They find it difficult to see nearby objects comfortably nd distinctly without corrective eye glasses. This defect is called Presbypoia.
ACOMMADATION
THE ability of the eye lens to adjust its focal length is called accommodation . however the focal length of the eye lens cannot be decrease below a certain minimum limit. To see an object comfortably nd distinctly the minimum distance at which objects c be seen is 25 cm
