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Explained: What is colour blindness, and can you get it later in life?

Colour blindness, also known as colour deficiency, is the inability to see colours in the normal way. Colour blind individuals often cannot distinguish between certain colours — usually greens and reds, and sometimes blues as well.

Men suffer from a higher incidence of colour blindness than women. Around the world, every tenth male is estimated to have some form of colour deficiency. (FIle Photo)

The Supreme Court has directed the Film and Television Institute of India (FTII) not to exclude candidates suffering from colour blindness from its courses on film making and editing and asked it to make changes to its curriculum instead.

The court agreed with the conclusion of an expert committee that the colour grading module of the editing course has “no relevance or nexus with the role of a film editor”.

“The conclusion (of the committee) shows a clear recommendation that all individuals will be allowed for all courses at FTII. Any limitation can be overcome,” the court said.

“FTII should make accommodation in its curriculum for candidates with colour blindness and the colour grading module in existing diploma and film editing course curriculum should be excluded or made elective.”

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Earlier in March 2017, Bombay High Court had declined to provide relief to another student who had been denied admission by FTII after a medical test showed he was suffering from colour blindness.

“We are of the view that the Petitioner being a candidate suffering from disability of colour blindness, he cannot claim admission in the course in question in which according to the FTII Rules framed by the expert body of the first Respondent (FTII) he cannot be allowed,” the court had said.

What is colour blindness?

Colour blindness, also known as colour deficiency, is the inability to see colours in the normal way. Colour blind individuals often cannot distinguish between certain colours — usually greens and reds, and sometimes blues as well.

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Two types of cells in the retina detect light — the “rods”, which distinguish between light and dark, and the “cones” that detect colour. There are three types of cones that see colour — red, green, and blue — and our brains use the information from these cells to perceive colour.

Colour blindness can be the result of the absence of one or more of these cone cells, or their failure to work properly. In a situation where all three cone cells are present but one of them is malfunctioning, mild colour blindness may occur.

Colour blindness may be of different kinds and degrees. Mildly colour blind people often see all colours properly only when the light is good; there are others who cannot tell one colour apart from the another no matter how good the light is.

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In the most severe kind of colour blindness, vision is black-and-white, that is, everything appears as a shade of grey. This is not very common.

Clarity usually not affected

Color blindness generally affects both eyes, and the condition remains roughly the same for as long as the individual is alive.

Unless the color blindness is of the most severe kind, the sharpness or clarity of vision is not affected. Many people are so mildly colour blind that they do not even realise that they have the condition.

Colour blindness cannot as yet be treated or reversed. However, it can be corrected to some extent by wearing special contact lenses or colour filter glasses. There is some research that suggests gene replacement therapy can help modify the condition.

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Detecting the condition

In the case of a child, parents can notice the deficiency for the first time when the child is beginning to learn colours. The child may have difficulty in seeing colours or in recognising the brightness of colours in ways that would be considered ‘normal’.

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The child may also show an inability to distinguish between shades of the same or similar colours. Parents and teachers often notice the child cannot tell between red and green, and blue and yellow.

What causes colour blindness

Most colour blind people are born with the condition (congenital colour blindness), but some can develop it later in life. Congenital colour vision deficiencies are usually passed on genetically.

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A problem with colour vision that arises later in life could be the result of disease, trauma, or ingested toxins. If colour blindness arises out of disease, one eye may be affected differently from the other, and the difficulty could worsen over time.

Medical conditions that may increase the risk of getting colour blindness include glaucoma, diabetes, Alzheimer’s, Parkinson’s, alcoholism, leukaemia, and sickle-cell anaemia.

Who is at risk?

Men suffer from a higher incidence of colour blindness than women. Around the world, every tenth male is estimated to have some form of colour deficiency. Men of Northern European descent are considered to be especially vulnerable.

With regard to India, the Supreme Court in the FTII case quoted from the report of the expert committee: “…Estimated 8% of male population and less than 1% female population have red and green colour deficiency being the most common form of colour-blindness.”

What you can or cannot do

Colour blindness impairs in some ways the ability to do certain kinds of jobs, such as being a pilot or joining the armed forces. However, whether you can or cannot do these jobs often depends on the severity of the colour blindness, and the rules in place in different jurisdictions.

In June 2020, India’s Ministry of Road Transport and Highways amended the Central Motor Vehicles Rules 1989 to enable citizens with mild to medium colour blindness to obtain a driver’s licence. The decision was taken after the Ministry received representations that colour blind citizens are not able to get a driver’s licence because restrictions specified in the requirements in the declaration about physical fitness (Form I) or the Medical certificate (Form IA) make it difficult, a government release said.

The release noted that medical experts had recommended that mild to medium colour blind citizens should be allowed to drive, and that restrictions should be put only on the severely colour blind citizens. “This is also allowed in other parts of the world,” the release said.

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First published on: 13-04-2022 at 02:24:54 pm
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