Biology

INVESTIGATORY
PROJECT
 AISSCE
2024-2025
BOARD ROLL NO-
CLASS XII-B
 INDEX
PAGE TOPIC
1-2 INTRODUCTION
3-6 TYPES OF COLOUR BLINDNESS
7-11 RED-GREEN COLOUR DEFICIENCY

12 CAUSE & OCCURRENCE

13 SYMPTOMS
14 DIAGNOSIS AND TESTS
15 MANAGEMENT AND TREATMENT
 Color Blindness
INTRODUCTION
Color blindness (color
vision deficiency) is a
fairly common condition
in which we don’t see
colors in the traditional
way. This happens when
cones (a type of nerve
cell in our eye retina)
aren’t working correctly.
Cones process light and
images as they enter our
eye and send signals to
our brain that allow us to
perceive color.
 Color Blindness
Color blindness usually doesn’t mean you can’t see
any colors. The vast majority of people with color
blindness see a range of colors, but they see some
colors differently than others do. They may also
have trouble telling the difference between
certain colors or shades. Some very rare forms of
color blindness make a person unable to see any
colors.

For most people, color blindness is inherited. That

means it’s passed down from your biological
parents — from the mother or birthing parent in
the most common red-green forms of color
blindness. But you can also acquire color vision
deficiency later in life due to medical conditions or
other reasons.
 Types of color
blindness
There are several types of color blindness, defined
according to which types of cones aren’t working
well. Cones are nerve cells in our eye that detect
colors in the visible spectrum of light. This
spectrum includes all the wavelengths that humans
can see. These range in length from 380 nanometers
(short), or nm, to 700 nanometers (long). Normally,
we are born with three types of cones:
Red-sensing cones (L cones): These cones
perceive long wavelengths (around 560
nanometers).
Green-sensing cones (M cones): These
cones perceive middle wavelengths
(around 530 nanometers).
Blue-sensing cones (S cones): These cones
perceive short wavelengths (around 420
nanometers).
 1) Trichromacy: All three types of cones are
present and working properly. We see all colors
on the visible spectrum of light in the traditional
way. This is full-color vision.
\

2) Anomalous trichromacy: We have all

three types of cones, but one type isn’t as
sensitive to light in its wavelength as it should
be. As a result, one does not see colors in the
traditional way, with variations from normal
ranging from mild to severe. In mild cases, you
may just confuse pale or muted colors. In more
severe cases, you may also confuse vivid and
pure (fully saturated) colors.
Dichromacy: One type of cone is missing. So,
we only have two types of cones (usually S
cones along with either L cones or M cones).
One sees the world through the wavelengths
that those two types of cones can perceive.
It’s hard to tell the difference between fully
saturated colors.

Monochromacy: We only have one type of

cone, or we have no cone function at all. One
has very limited or no ability to see color.
Instead, one sees the world in varying shades
of gray.

Normal Dichromatic Monochromatic

vision vision vision
 Red-green color
deficiency

Red-green color deficiency is the most

common type of color blindness. It affects
how we see any color or shade that has some
red or green in it. There are four main
subtypes:
 Protanopia: Our red
sensing cones are
missing. So, one can’t
perceive red light. One
mostly see colors as
shades of blue or gold.
One may easily confuse
different shades of red
with black. One may also
confuse dark brown with
dark shades of other
colors, including green,
red or orange.
 Deuteranopia: Our green sensing
cones are missing. So, one can’t
perceive green light. One mostly see
blues and golds. One may confuse
some shades of red with some
shades of green. One may also
confuse yellows with bright shades
of green.
Protanomaly: In this we have all three
cone types, but our red sensing cones
are less sensitive to red light than
they should be. Red may appear as
dark gray, and every color that
contains red may be less bright.
 Deuteranomaly: You have all three
cone types, but your green sensing
cones are less sensitive to green light
than they should be. You see mostly
blues, yellows and generally muted
colors.
Who does color blindness affect?

Inherited color blindness mostly affects men and

people assigned male at birth (AMAB). This is due to
its genetic inheritance pattern (X-linked recessive).
People can also acquire color blindness due to
certain medical conditions, medications or
environmental exposures.

How common is color blindness?

Among people of Northern European ancestry, red-
green color blindness affects about 1 in 12 people
AMAB and 1 in 200 people AFAB. These numbers vary
by ethnicity. Some research shows that Europeans
have the highest prevalence of color
blindness.Overall, around 300 million people around
the world have some form of color blindness (mostly
red-green).
 Symptoms
Telling the difference between certain colors
or shades.
Seeing the brightness of certain colors.

it’s important for children to have a

comprehensive eye exam that includes
colorblind testing before starting school.
Many tests and other classroom materials
rely on color to convey information or
measure students’ learning. Children
who see colors differently may struggle
with these materials.
Diagnosis and Tests
The Ishihara test is the most common test eye
care providers use to diagnose red-green color
blindness. For this test, a provider shows us a
series of color plates. Each plate contains a
pattern of small dots. Among those dots,
there’s a number (or shape for young
children). We identify what we can see on each
plate. Some plates include numbers that we
can only see with full-color vision.
 Management and
Treatment
Currently, there’s no medical treatment or cure
for people with inherited color blindness. If one
have acquired color blindness, our healthcare
provider will treat the underlying condition or
adjust our medications as needed. This may
help improve one to color vision.

Color-blind glasses may provide a richer color

experience for people with mild forms of
anomalous trichromacy. The glasses enhance
the contrast between colors so people with
color vision deficiency can see the differences
more clearly. But they don’t allow us to see any
new colors, and the results vary based on the
individual. Plus, it’s important to know that
these glasses aren’t a cure and won’t correct
any issues with our cones.
THANK
YOU!
NIRALI SARAF