An inherited form of defective colour vision in which red and green hues are confused, and 'red' cones are filled with 'green' cone opsin, is called:
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Correct option is C

Protanopia is a type of inherited red-green colour blindness where individuals lack red cones or have defective red cones. As a result, the 'red' cones are filled with 'green' cone opsin, causing difficulty in distinguishing between red and green hues.

Key Features of Protanopia:

• Red and green colours appear similar, leading to confusion.

• It is caused by a mutation or absence in the long-wavelength (L) photopigments of the retina.

Information Booster: 

Trichromatic Theory of Vision (Young-Helmholtz Theory)

• Definition: Proposes that color vision is based on the activity of three types of photoreceptor cells in the retina (cones), each sensitive to different wavelengths of light.

• Three Types of Cones:

• S-Cones: Sensitive to short wavelengths (blue).

• M-Cones: Sensitive to medium wavelengths (green).

• L-Cones: Sensitive to long wavelengths (red).

• Color Perception:

• Colors are perceived through the combination of stimulation from these three types of cones.

• For example:

• Equal stimulation of all cones = white light.

• Stimulation of L- and M-cones = yellow.

Additional Information:

• A. Deuteranopia: This is another form of red-green colour blindness but involves the absence or defect in green cones.

• B. Tritanopia: This refers to blue-yellow colour blindness caused by the absence of short-wavelength (S) cones.

• D. Myopia: A refractive error where distant objects appear blurry, unrelated to colour vision defects.