Certified Ophthalmic Medical Technologist (COMT) Practice Exam

How does the color sensitivity of cones respond to light wavelengths?

1. They are not sensitive to any color wavelengths

2. They respond selectively to specific wavelengths corresponding to their pigment type

3. They respond to all light wavelengths equally

4. They are only sensitive to ultraviolet light

The correct answer is: They respond selectively to specific wavelengths corresponding to their pigment type

The response of cones to light wavelengths is centered on their ability to selectively respond to specific ranges of wavelengths, which corresponds to the pigment types present in each type of cone cell. Humans have three types of cones: short-wavelength cones (S-cones), medium-wavelength cones (M-cones), and long-wavelength cones (L-cones). Each of these types contains different photopigments that are sensitive to various parts of the light spectrum – specifically, blue, green, and red light, respectively. This selective sensitivity enables the human visual system to perceive a wide range of colors through a process called color vision or trichromatic vision. When light hits these photoreceptors, the varying responses of the different cones create a combination of signals sent to the brain, which interprets them as distinct colors. Thus, the principle that cones respond selectively to specific wavelengths is fundamental to human color perception and is grounded in the biological processes of the photoreceptors in the retina.