Biology IP
Biology IP
Biology IP
ACKNOWLEDGEMENT
Last but not the least, I would like to thank all those
who had helped directly or indirectly towards the
completion of this project.
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INDEX
1. Introduction 5
2. Human Eye 6
3. Adaptation of an Eye 8
4. Accomodation of an Eye 10
7. Conclusions 15
8. Bibliography 16
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INTRODUCTION
HUMAN EYE
1. The human eye is a sense organ, part of the sensory nervous system
that reacts to visible light and allows us to use visual information for
various purposes including seeing things and keeping our balance.
ADAPTATION OF AN EYE
1. Our eyes have the ability to adapt the sight on the basis of
the environment, whether it has brightness or dimness.
2. Adaptation is the ability of the retina of the eye to adjust to
various levels of light. It depends on the number of
photoreceptor cells, that is, rods and cones.
3. Rods are those cells which are responsible for vision at low
light levels, whereas cones are those cells which are
responsible for vision at high light levels.
4. Rods can be found at the periphery of the retina and do not
impart color vision, hence, they are not differentiated.
5. Cones can be found at the center of the retina and can
impart color vision, differentiating into three main colors:
Red, green and blue.
6. The POWER OF ADAPTATION is the ability of an eye to
change the size of the aperture of the pupil, on the basis of the
amount of light falling into the eye.
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2) The radial muscles relax and the circular muscles contract. Thus,
cones get activated after some time when we see out of the bright
screen of the computer. Similar cases can be applied when we see the
Sun with naked eyes, thus, floaters get developed after getting
exposure from sunlight.
2)The radial muscles contract and the circular muscles relax. Thus,
the rods get activated after some time for illumination.
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ACCOMODATION OF AN EYE
1. MYOPIA (Near-sightedness):
1) It is the defect of an eye in which the light rays do not focus on the
surface of the retina but in front of it.
2) This results in images being blurry when perceived.
3) Thus, distant images appear out of focus but objects nearby are
seen clearly.
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2. HYPERMETROPIA (Far-sightedness):
1) It is the defect of an eye where the image of a nearby object is
formed behind the retina.
2) This results in difficulty in focusing nearby objects, but can clearly
see distant objects.
3) It can occur if the eyeball is small-sized leading to image formation
behind the retina. It can cause watering, blurry vision, tiredness in
eyes and headaches, especially for those who are associated with
computer work.
4) It can be corrected through the usage of convex or converging
lenses.
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We know about some basic harmful effects on using the computer for
a longer period of time, which can mainly harm our vision. But not
only on the basis of vision, we may complain about headaches and
pains in our wrists, arms and necks. This may also cause muscle pain
due to fatigue, so it could be better for us to take some breaks and get
ready to work.
When we use the computer for a very long period of time, we suffer
from backache, headaches, weight gain or loss, disturbances in sleep,
blurred or strained vision, etc. The late night computer sessions cut
into much needed sleep time, which can cause long term sleep
deprivation. This may lead to drowsiness, difficulty in concentrating
and depression of the immune system.
The prolonged use of the computer can cause physical damage. Using
the mouse and the keyboard for many hours everyday can lead to
repetitive stress injuries. The back problems are common among the
people who spend a lot of time sitting at the computer desks.
PREVENTIONS:
1) We should rest our eyes to prevent eye problems.
2) We can take a 10 minute break every hour when we are working on
the computer.
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SYMPTOMS:
1) Blurred vision
2) Headaches
3) Dizziness and fatigue
4) Neck pain
5) Difficulty refocusing the eyes
CAUSES:
1) Poor lighting.
2) Glare on a digital screen
3) Improper viewing distances
4) Poor sitting posture
5) Uncorrected vision problems
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PREVENTIONS:
1) We should minimize the discomfort from blue light and glare.
2) We can adjust work area and computer for comfort,
3) We can take alternative task breaks throughout the day.
4) We must take care of our minor vision problems to be properly
corrected.
TREATMENT:
Eyeglasses or contact lenses prescribed for general use may not be
adequate for computer work. Special lens designs or lens powers may
help to maximize visual abilities and comfort.
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CONCLUSIONS
1) Our human eye is the most sensitive and important organ
through which we can see our surroundings. Computer
devices, especially mobile phones, desktops and laptops also
play an important role in our life, but we should not use them
for a longer period of time in order to prevent any visionary
defects in our eyes. So, we should use them to a particular
limit everyday.
BIBLIOGRAPHY
1) NCERT Biology Textbook, Class 11th
2) en.wikipedia.org
3) www.byjus.com
4) www.online-sciences.com
5) www.ncbi.nlm.nih.gov
6) www.aoa.org