"Left eye closed, right eye looking through the notch of the rear sight so as to perceive the object aimed at it." — Moss, 1914

Aim

"Left eye closed, right eye looking through the notch of the rear sight so as to perceive the object…

"Now Argus had a hundred eyes in his head, and never went to sleep with more than two at a time, so he kept watch of Io constantly." —Bulfinch, 1897

Argus

"Now Argus had a hundred eyes in his head, and never went to sleep with more than two at a time, so…

"The eyes, which are among the most wonderful objects in nature, are almost always of the kind called <em>compound</em>, that is to say, they consist of a multitude of little hexagonal facets, brought close together on each side of the head, each furnished with a cornea, a lens, a coating of pigment, and a nervous filament, and being in fact a true eye." &mdash; Goodrich, 1859

Eyes of a Bee

"The eyes, which are among the most wonderful objects in nature, are almost always of the kind called…

Blood vessels of the capsulopupillary membrane of a newborn kitten.

Blood Vessels of the Capsulopupillary of a Kitten

Blood vessels of the capsulopupillary membrane of a newborn kitten.

"Anterior end of body of Branchiostoma. d, chorda dorsalis; e, spinal cord; f, cartilaginous rods; g, eye; h, branchial rods; i, labial cartilage; k, oral cirrhi." &mdash; Encyclopedia Britannica, 1893

Brachiostoma

"Anterior end of body of Branchiostoma. d, chorda dorsalis; e, spinal cord; f, cartilaginous rods; g,…

The capsule of T&eacute;non consists of a thin membrane which envelops the eyeball from the optic nerve to the ciliary region, separating it from the orbital fat and forming a socket in which it plays. Shown is the capsule of T&eacute;non. The aponeurosis is seen from behind forward on the posterior hemisphere of the globe. Labels: a, Cellulofibrous intermuscular lamina; b, deep leaf of the sheath incised at the point where it leaves the muscle to fold itself on the posterior hemisphere when it forms the posterior capsule; d, Partly incised; c, Serous membrane.

Capsule of Ténon

The capsule of Ténon consists of a thin membrane which envelops the eyeball from the optic nerve…

The eye of a cat in its contracted state.

Contracted Cat Eye

The eye of a cat in its contracted state.

The eye of a cat in its dilated state.

Dilated Cat Eye

The eye of a cat in its dilated state.

This illustration displays a way in which to correct cataracts through operation.

Cataract Operation

This illustration displays a way in which to correct cataracts through operation.

Vertical section of the chorioid and inner part of the sclera.

Vertical Section of the Chorioid and Sclera

Vertical section of the chorioid and inner part of the sclera.

A. A cone and two rods from the human retina (modified from Max Schultze); B. Outer part of rod separated into discs.

Cones and Rods of Retina

A. A cone and two rods from the human retina (modified from Max Schultze); B. Outer part of rod separated…

Section of human cornea.

Section of Cornea

Section of human cornea.

Vertical section of the cornea.

Vertical Section of the Cornea

Vertical section of the cornea.

A portion of the corona ciliaris magnified. The ciliary processes and the ciliary folds.

Magnified Corona Ciliaris

A portion of the corona ciliaris magnified. The ciliary processes and the ciliary folds.

The simple eye of a jellyfish

Eye

The simple eye of a jellyfish

A section of the human eye.

Eye

A section of the human eye.

"Next in order is the aqueous humor, b, e, in the middle of which is the iris, d, c. Behind the pupil we have the crystalline lens, f, and then the vitreous humor, h, filling all the interior of the ball of the eye. m indicates the retina, which is an expansion of the optic nerve, n. k is the choroid coat, a membrane interposed between the retina and the sclerotic coat; it terminates in form in a series of folds or filaments, g, called the ciliary ligament or process." &mdash;Wells, 1857

Eye

"Next in order is the aqueous humor, b, e, in the middle of which is the iris, d, c. Behind the pupil…

An eye

Eye

An eye

An eye

Eye

An eye

An eye

Eye

An eye

An eye

Eye

An eye

"a, sclerotic membrane; b, cornea; d, retina; o, optic nerve; v, vitreous humor." -Comstock 1850

Eye

"a, sclerotic membrane; b, cornea; d, retina; o, optic nerve; v, vitreous humor." -Comstock 1850

"The human eye-essential parts shown in section." &mdash;Croft 1917

Eye

"The human eye-essential parts shown in section." —Croft 1917

The eye.

Eye

The eye.

The human eye. Labels: a, crystalline lens; b, retina; c, cornea; d, sclerotic; e, choroid; g, ciliary processes; h, vitreous humor; k, pupil; i, iris; o, optic nerve.

Eye

The human eye. Labels: a, crystalline lens; b, retina; c, cornea; d, sclerotic; e, choroid; g, ciliary…

The eye and eyebrow of a person's face used for seeing.

Eye

The eye and eyebrow of a person's face used for seeing.

A human eye, used for sight, pictured with an eyebrow.

Eye

A human eye, used for sight, pictured with an eyebrow.

An illustration of an eye.

Eye

An illustration of an eye.

The eye and its muscles. Labels: o, the nerve of sight; a, one of the muscles of the eye.

The Eye and its Muscles

The eye and its muscles. Labels: o, the nerve of sight; a, one of the muscles of the eye.

Front view of left eye, with eyelid partly removed to show lachrymal gland (tear-producing gland), and lachrymal duct (tear duct).

Eye and Lachrymal Gland

Front view of left eye, with eyelid partly removed to show lachrymal gland (tear-producing gland), and…

Ciliary processes, as seen from behind. Labels: 1, posterior surface of the iris, with the sphincter muscle of the pupil; 2, anterior part of the choroid coat; 3, one of the ciliary processes of which about seventy are represented.

Ciliary Processes of the Eye as Seen from Behind

Ciliary processes, as seen from behind. Labels: 1, posterior surface of the iris, with the sphincter…

The relative position and attachment of the muscles of the left eyeball.

Eye Muscles

The relative position and attachment of the muscles of the left eyeball.

"The external bones of the temple are supposed to be removed in order to render visible the muscular arrangements. The muscle, 1, raises the eye-lid, and is constantly in action while we are awake. During sleep, the muscle being in repose and relaxed, the eye-lid falls and protects the eye from the action of light. The muscle, 4, turns the eye upwards; 5, downwards; 6, outwards; and a corresponding one on the inside, not seen in the figure, turns it inwards. No. 2 and 10 turn the eye round its axis. No. 11 is the great optic nerve, which conveys the sensation to the brain. If this nerve were cut, notwithstanding the eye might be in other respects perfect, the sense of sight would be destroyed." &mdash;Wells, 1857

Eye Muscles

"The external bones of the temple are supposed to be removed in order to render visible the muscular…

Right orbit opened to show the nerves of the eye. Labels: a, optic; b, motor oculi; c, pathetic; d, ophthalmic division of fifth pair; d', lachrymal; d&quot;, supraorbital; d&quot;', nasal; c, abducens; e', rectus externus muscle; f, orbital branch os superior maxillary nerve.

Eye Nerves of a Horse

Right orbit opened to show the nerves of the eye. Labels: a, optic; b, motor oculi; c, pathetic; d,…

A, section through the compound eye of a crayfish. Labels: 1, cornea; 2, crystaline cones; 3, retinulae; 4, pigment cells; 5, cuticle; 6, epithelium; n, optic nerve; g, ganglia. B, A single element (ommatidium) from the compound eye of a crayfish. Labels: 1, corneal lens; 2, corneal cells; 3, crystalline cone cells; 4, 5, outer and inner parts of the crystalline cone; p, pigment cells; r, retinula; R, rhabdome; b, basement membrane.

Eye of a Crayfish

A, section through the compound eye of a crayfish. Labels: 1, cornea; 2, crystaline cones; 3, retinulae;…

Longitudinal section through the pineal eye of a lizard. The eye is located in the middle of the dorsal side of the head and is covered by the translucent scaled. The outer wall of the eye vesicle is thickened to form a lens, while the inner pigmented wall is the retina from which the nerve proceeds.

Eye of a Lizard

Longitudinal section through the pineal eye of a lizard. The eye is located in the middle of the dorsal…

Diagrammatic sketch of a vertical longitudinal section through the eyeball of a human fetus of four weeks. The section is a little to the side, so as to avoid passing through the ocular cleft; c, the cuticle where it becomes later the corneal epithelium; l, the lens; op, optic nerve formed by the pedicle of the primary optic vesicle; vp, primary medullary cavity or optic vesicle; p, the pigment layer of the retina; r, the inner wall forming the retina proper; vs, secondary optic vesicle containing the rudiment of the vitreous humour.

Eye of Fetus of Four Weeks

Diagrammatic sketch of a vertical longitudinal section through the eyeball of a human fetus of four…

Transverse vertical section of the eyeball of a human embryo of four weeks. The anterior half of the section is represented: pr, the remains of the cavity of the primary optic vesicle; p, the inner part of the outer layer forming the retinal pigment; r, the thickened inner part giving rise to the columnar and other structures of the retina; v, the commencing vitreous humour within the secondary optic vesicle; v', the ocular cleft through which the loop of the central blood vessel, a, projects from below; l, the lends with a central cavity.

Eye of Fetus of Four Weeks

Transverse vertical section of the eyeball of a human embryo of four weeks. The anterior half of the…

Section through the cup-shaped eye of a gastropod. Labels: e, epithelium covering body; cv, vitreous body; R, retina; N, nerve.

Eye of Gasteropod

Section through the cup-shaped eye of a gastropod. Labels: e, epithelium covering body; cv, vitreous…

Section through the eye of a waterbeetle. Labels: l, chitinous lens; cv, transparent cells; pg, pigment cells; R, retina.

Eye of Waterbeetle

Section through the eye of a waterbeetle. Labels: l, chitinous lens; cv, transparent cells; pg, pigment…

The illustration of putting lenses in front of the eye. The focal point of the image is reflected into the eye. The focal point in the lens will end past the eye, creating a blurry image.

Optical Position and Size of Image Through Lens in Front of Eye

The illustration of putting lenses in front of the eye. The focal point of the image is reflected into…

A section of the eye seen from within. Labels: 1, The divided edge of the three coats. 2, The pupil. 3, The iris. 4, The ciliary processes. 5, The scolloped border of the retina.

A Section of the Eye Seen from Within

A section of the eye seen from within. Labels: 1, The divided edge of the three coats. 2, The pupil.…

A section of the eye. Labels: 1, The sclerotic coat. 2, The cornea. 3, The choroid coat. 6, The iris. 7, The pupil. 8, The retina. 10, 11, Chambers or cavities of the eye that contain the aqueous humor. 12, The crystalline lens. 13, The vitreous humor. 15, The optic nerve. 14, 16, An artery of the eye.

A Section of the Eye

A section of the eye. Labels: 1, The sclerotic coat. 2, The cornea. 3, The choroid coat. 6, The iris.…

"It was during the siege of Methone that Philip had the misfortune to lose on of his eyes. A random arrow discharged from the rampart fell square in the king's face and destroyed one-half of his sight. When the arrow-head was drawn away, it was found to contain the following label: "Astor to Philip's right eye." It appeared on inquiry that the unerring missile had been discharged by an offended archer who has recently offered his services to the king and been rejected. He hd represented to Philip that his skill with the bow was great that he could kill a small bird on the wing. The king not believing the story had put off the applicant with the remark, "Well, well, I shall make use of thee when I go to war with the starlings." Astor has then joined the Methoneans and now vindicated his skill in a way never to be forgotten."&mdash;Ridpath, 1885

Astor to Philip's Right Eye

"It was during the siege of Methone that Philip had the misfortune to lose on of his eyes. A random…

The eye, after cutting away the sclerotic coat and cornea, to show the vessels of the choroid coat; magnified.

Choroid Coat of the Eye

The eye, after cutting away the sclerotic coat and cornea, to show the vessels of the choroid coat;…

Section through the eye carried through the ciliary processes. Labels: 1, Cornea; 2, membrane of Descemet; 3, sclerotic; 3', cornea-scleral junction; 4, canal of Schlemm; 5, vein; 6, nucleated network on inner wall of canal Schlemm; 7, lig. pectinatum iridis, abc; 8, iris stroma; 9, pigment of iris; 10, ciliary processes; 11, ciliary muscles; 12, choroid tissue; 13, meridional and 14, radiating fibers of ciliary muscle; 15, ring-muscle of Muller; 16, circular or angular bundles of ciliary muscle.

Ciliary Processes of the Eye

Section through the eye carried through the ciliary processes. Labels: 1, Cornea; 2, membrane of Descemet;…

"...and the cornea will become too flat, or not suffciently convex, to make the rays of light meet at the proper place, and the image will therefore tend to be formed beyond the retina, instead of before it..." -Comstock 1850

Cornea too Concave on Eye

"...and the cornea will become too flat, or not suffciently convex, to make the rays of light meet at…

"Diagram illustrating the Manner in which the Image of an Object is inverted on the Retina." &mdash; Blaisedell, 1904

Diagram of the eye

"Diagram illustrating the Manner in which the Image of an Object is inverted on the Retina." —…

The right eye in horizontal section.

Horizontal Section of Eye

The right eye in horizontal section.

Diagram showing the anterior four-fifths of the eyeball.

Human Eye

Diagram showing the anterior four-fifths of the eyeball.

"Section of the human eye." &mdash; Blaisedell, 1904

Human eye

"Section of the human eye." — Blaisedell, 1904

Diagrams of how an image is displayed with a normal eye (top image), myopic or nearsighted eye (middle image), and a hypermetropic or far-sighted eye. In a human, the retina "sees" an image upside down and the brain rights the image.

Human Eye

Diagrams of how an image is displayed with a normal eye (top image), myopic or nearsighted eye (middle…

The lachrymal apparatus of the right eye.

Lachrymal Apparatus of the Eye

The lachrymal apparatus of the right eye.

Lens of the eye. The rays of light are brought nearer together by the lenses of the eye, just as they are by the lenses of the telescope.

Lens of the eye

Lens of the eye. The rays of light are brought nearer together by the lenses of the eye, just as they…

"Diagram showing the Change in the Lens during Accomadation. On the right the lens is arranged for distant vision, the cilliary muscle is relaxed, and the ligament <em>D</em> is tense, so flattening by its compression the front of the lens <em>C</em>, on the left the muscle <em>A</em> is acting, and this relaxes the ligament and allows the lens <em>B</em> to become more convex, and so fitted for the vision of near objects." &mdash; Blaisedell, 1904

Lens of the eye

"Diagram showing the Change in the Lens during Accomadation. On the right the lens is arranged for distant…

"Human Eye, in Median Vertical Anteroposterior Section. (Ciliary processes shown, through not all lying in this section.) A, anterior, and A', posterior chambers of aqueous humor; a, central artery of retina; C, cornea; Ch, choroid; cj, conjunctiva; cm, ciliary muscle; cp, ciliary processs; H, hyaloid; I, iris; L, crystalline lens in its capsule (the reference-line passes through the pupil); l, l', insertion of tendon of superior and inferior rectus muscles; o, optic nerve; P, canal of Petit; R, retina; S, sclerotic; s, s', circular sinus or canal of Schlemm; V, vitreous body filling back part of the eye." -Whitney, 1911

Median Vertical Anteroposterior Section of Eye

"Human Eye, in Median Vertical Anteroposterior Section. (Ciliary processes shown, through not all lying…

"Showing how the image of an object which is seen is formed on the retina of the eye." &mdash;Croft 1917

Eye Focusing on Object

"Showing how the image of an object which is seen is formed on the retina of the eye." —Croft…

Sagittal section of the eye, showing superior and inferior fornices of the conjuctiva.

Sagittal Section of the Eye

Sagittal section of the eye, showing superior and inferior fornices of the conjuctiva.

The upper half of a sagittal section through the front of the eyeball.

Sagittal Section Through the Eye

The upper half of a sagittal section through the front of the eyeball.

Section of the eye, showing the relations of the cornea, sclera, and iris, together with the Ciliary muscle and the cavernous spaces near the angle of the anterior chamber.

Section of the Eye

Section of the eye, showing the relations of the cornea, sclera, and iris, together with the Ciliary…