Assignment
Assignment
Assignment
GROUP MEMBERS:
AJAY.S(10102)
AKILESH. M(10103)
DERIN.C(10104)
THARUN KIRUTHIK.S.R(10109)
VISHWANTH.S.G(10110)
YASHVANTH.M.K(10111)
CLASS: X
Sub:Physics
RUBRICS:
1.
2.
3.
4.
ACKNOWLEDGEMENT
Iris
It is colored part of the eye.
It holds the pupil and also adjust the size of pupil according to the intensity of light.
Pupil:
It is black in color and absorbs all the light rays falling on it.
It gets constricted when the intensity of light is high.
It gets expanded when the intensity of light is low.
Ciliary muscles
They hold the lens.
They adjust the focal length of the lens.
Retina :
It is the screen of an eye where image is formed.
It consists of two types of cells:
Cone cells: those cells which respond to colors.
Rod cells: those cells which respond to the intensity of light.
MYPOIC EYE:
Nearsightedness, or myopia, as it is medically
termed, is a vision condition in which people can
see close objects clearly, but objects farther away
appear blurred.
CORRECTION: For most people with myopia, eyeglasses are the primary choice for correction. For this
correction concave lenses were used. Depending on the amount of myopia, you may only need to wear
glasses for certain activities, like watching a movie or driving a car. Or, if you are very nearsighted, you
may need to wear them all the time. Generally, a single-vision lens is prescribed to provide clear vision
at all distances.
Concave lenses: Concave lenses are most commonly used to correct myopia which is also called
nearsightedness. The eyeball of a person suffering from myopia is too long, and the images of faraway objects
fall short of the retina. Therefore, concave lenses are used in glasses which correct the shortfall by spreading
out the light rays before it reaches the eyeball. This enables the person to see far away objects more clearly.
HYPERMETROPIA:
The person suffering from hypermetropia will have difficulty in focusing on nearby objects, but can clearly see distant
objects. Accommodation is the process used to treat hypermetropia without any defects in vision in the early stages.
CAUSES: Hypermetropia is mainly caused due to certain structural defects in the retina. Structural defects
include:
Small-sized eye-ball
The cornea is flatter than usual
CONVEX LENS: Convex lenses are used in spectacles in the case of hypermetropia, commonly known as
long-sightedness. In the case of hypermetropia, the person with this issue has difficulty in seeing clearly the
objects that are close to them. Convex lenses can help by focussing all the incident light, particularly at a
point on the retina, allowing for a much clearer vision. The convex lens decreases the image distance. Since
the incident light is refracted before it enters the eye, the image of close objects is more centered upon the
retinal surface Convex lenses are used in magnifying glasses and telescopes because they have the ability to
enlarge an object when viewed through them.
PRESBYOPIA:
Presbyopia is physiological insufficiency of accommodation associated with the aging of the eye that
results in progressively worsening ability to focus clearly on close objects. Also known as age-related
farsightedness, it affects many adults over the age of 40. A common sign of presbyopia is difficulty reading
small print which results in having to hold reading material farther away. Other symptoms associated can
be headaches and eyestrain. It is corrected by Bifocal lens.
MYOPIC, HYPERMETROPIC, PRESBYOPIC EYE
S.No Name Type of defection Age Corrective lens Power
Age Group 12 - 18
Age Group 19 - 30
Age Group 31 - 50
Age Group 51 - 80
12 DEFECTS OF VISION
10
0
MYOPIA HYPERMETEROPIA PRESBYOPIA
Let us take the power of Akilesh to find focal length: the power of Akilesh is -4D
100
f
4
f 25cm