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"A representation of the manner in which the image is formed in the eye, when the cornea or crystalline lens is flattened. The perfect image would be produced at m m, behind the retina, and, of course, beyond the point necessary to secure perfect vision." —Wells, 1857

Flattened Eye

"A representation of the manner in which the image is formed in the eye, when the cornea or crystalline…

"A representation of the manner in which the image is formed in the eye of a near-sighted person. The curvature of the cornea, s s, and of the crystalline lens, c c, is so great that the image is formed at m m in advance of the retina." —Wells, 1857

Near-sighted

"A representation of the manner in which the image is formed in the eye of a near-sighted person. The…

"A representation of the manner in which the image is formed upon the retina in the perfect eye. The curvature of the cornea, s s, and of the crystalline lens, c c, is just sufficient to cause the rays of light proceeding from the image, e e, to converge the right focus, m, upon the retina." —Wells, 1857

Perfect Eye

"A representation of the manner in which the image is formed upon the retina in the perfect eye. The…