Bio 203 Final Exam Correct Questions & Answers

emmetropia - ANSWER normal refraction presbyopia - ANSWER natural elasticity of the lens is lost w/ age. Lens is unable to assume more spherical shape for viewing near objects. requires a convex lens hyperopia - ANSWER farsightedness, eyeball is too short, light rays converge toward a point behind the retina. requires a convex lens myopia - ANSWER nearsightedness, eyeball is too long, light rays hit in the front of the retina. requires a concave lens. astigmatism - ANSWER irregular curvature of the cornea. Horizontal lines may be focused, but vertical lines blurred and vice versa. requires a cylindrical lens. cataract - ANSWER lens loses transparency and becomes opaque. If clear vision is lost, may need to be removed by cataract surgery and replaced with an artificial lens trichromats - ANSWER normal color vision (the Young-