Hunter vs prey eyes human12/7/2023 ![]() While sight is primarily independent in the two chameleon eyes, the eye that first detects prey will guide accommodation in the other eye. Using corneal accommodation for depth perception makes the chameleon the only vertebrate to focus monocularly. The combination of a negative lens and a positive cornea in the chameleon eye allow for accurate focusing by corneal accommodation. Monocular focusing and corneal accommodation The cornea improves sight resolution in a narrower field of vision. The increased power of the cornea also contributes to more precise focusing than in other vertebrates. While the lens are negative, the cornea of chameleon eyes are positive, meaning that it is convex. ![]() In fact, image magnification in chameleons is higher in a scaled comparison to all other vertebrates eyes. This increases retinal image size, allowing more precise focusing. Negative lens Ĭhameleon eyes feature a negative lens, meaning that the lens is concave. Finally, “striated rather than smooth ciliary muscle in sauropsids” allows for rapid focusing. Each eye focuses independently, which is achieved by the chameleon eye’s unique anatomy of separated nodal and center points of the eye. ![]() With a negative (nearsighted or concave) lens and a positive (farsighted or convex) cornea, chameleons use a method of monocular focusing to judge distance called corneal accommodation. An eyelid fused to the pupil protects the eyes, leaving only a small part exposed. Chameleon eyes protrude laterally from the head, giving the lizard panoramic sight. This allows a chameleon to watch an approaching object while simultaneously scanning the rest of its environment. The angle, or amplitude, of eye movement in chameleons is very large for a vertebrate and the eyes move independently of each other. The development of the chameleon visual system could have evolved to aid in prey capture and/or in predator avoidance. Unique features of chameleon vision include a negative lens, a positive cornea, and monocular focusing. The chameleon is among the most highly visually-oriented lizards, using this sense in prey capture, mating behavior, and predator avoidance.
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