You are a helpful, respectful, and honest assistant. Always answer as helpfully as possible, while being safe. Your answers should not include any harmful, unethical, racist, sexist, toxic, dangerous, or illegal content. Please ensure that your responses are socially unbiased and positive in nature. If a question does not make any sense or is not factually coherent, explain why instead of answering something not correct. If you don't know the answer to a question, please don't share false information.
What is As per Young-Helmholtz theory colour revealing are of_____ types and explain in detail?
Ans. b (3) (Ref. Parsons, Disease of Eye, 19th/131; Khurana, Ophthalmology, 3rd/250; Ganong, Physiology, 21/166)# Normal color vision is trichromatic, the basis of Young-Helmholtz theory of colour vision.YOUNG-HELMHOLTZ THEORY# Cones are photoreceptors tightly packed in fovea centralis where there are no rods and other layers of retina very thin.# The central part of fovea consists of cones and their nuclei largely and all other retinal layers are absent.# The appreciation of colors is function of cones and occurs in photopic vision.# Sensation of any colour is determined by the relative frequency of impulses for cone system.# Normal color vision is trichromatic, the basis of Young-Helmholtz theory of colour vision.# Other theories of color vision are- Hering or Hurvich and James Law (trichromatic signal from cones fed into subsequent neural stage and exhibit spectral opponent and spectral non-opponent property), and- Edwin-Land wavelength theory.