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The Human Sensory Systems: Sight ClipArt gallery offers 189 illustrations related to human vision.

Section of the iris. Anterior surface magnified.

Section of the Iris

Section of the iris. Anterior surface magnified.

The lachrymal apparatus, used in tear production.

Lachrymal Apparatus

The lachrymal apparatus, used in tear production.

The lachrymal apparatus (the skin of the lids has been removed), which functions in tear production.

Lachrymal Apparatus

The lachrymal apparatus (the skin of the lids has been removed), which functions in tear production.

Lachrymal apparatus, which produces tears (eyelid skin has been removed).

Lachrymal Apparatus

Lachrymal apparatus, which produces tears (eyelid skin has been removed).

View of the lachrymal gland and nasal duct. Labels: 1, The lachrymal gland. 2, Ducts leading from the lachrymal gland to the upper eyelid. 3, The "tear points". 4, The nasal sac. 5, The termination of the nasal duct.

View of the Lachrymal Gland and Nasal Duct

View of the lachrymal gland and nasal duct. Labels: 1, The lachrymal gland. 2, Ducts leading from the…

The lacrimal apparatus consists of the lacrimal gland, which secretes the tears, and its excretory ducts, which convey fluid to the surface of the eye. This fluid is carried away by the lacrimal canals into the lacrimal sac, and along the nasal duct into the cavity of the nose.

Lacrimal Apparatus

The lacrimal apparatus consists of the lacrimal gland, which secretes the tears, and its excretory ducts,…

The two portions of the lacrimal gland, as seen in a lateral sagittal section of the orbit. A: Mode of entrance for extirpation of the palpebral portion of the lacrimal gland. B: Mode of entrance for extirpation of the orbital portion of the lacrimal gland.

Lacrimal Gland

The two portions of the lacrimal gland, as seen in a lateral sagittal section of the orbit. A: Mode…

Alveoli of lacrimal gland.

Alveoli of Lacrimal Gland

Alveoli of lacrimal gland.

The lacrimal (lachrymal) gland is an oval gland in the orbital portion of the frontal bone. Its tear ducts open by a row of orifices on the upper and outer portion of the palpebral conjunctiva. It's secretion, the tears, lubricates the surface of the eyeball.

The Lacrimal Gland

The lacrimal (lachrymal) gland is an oval gland in the orbital portion of the frontal bone. Its tear…

The crystalline lens, which is a bi-convex, elastic, transparent body, enclosed in a capsule, held in place by a suspensory ligament, and situation immediately behind the pupil ad in front of the vitreous body, in the fossa patellaris of which its posterior and most convex surface rests.

Lens of the Eye

The crystalline lens, which is a bi-convex, elastic, transparent body, enclosed in a capsule, held in…

Flexible crystalline lens of the eye.

Lens of the Eye

Flexible crystalline lens of the eye.

Laminated structure of the crystalline lens. The laminae are split up after hardening in alcohol. Labels: 1, the denser central part or nucleus; 2, the successive external layers.

Crystalline Lens

Laminated structure of the crystalline lens. The laminae are split up after hardening in alcohol. Labels:…

The crystalline lens, hardened and divided.

Crystalline Lens

The crystalline lens, hardened and divided.

"Diagram showing how the lens changes its form for near and far sight." — Tracy, 1888

Eye lens

"Diagram showing how the lens changes its form for near and far sight." — Tracy, 1888

Section through the equator of the lens. Showing gradual transition of the epithelium into lens fibers.

Section Through Lens

Section through the equator of the lens. Showing gradual transition of the epithelium into lens fibers.

Terms used in the orientation of the lens.

Terms Used in the Orientation of the Lens

Terms used in the orientation of the lens.

A convex lens, bends the ray of light which pass through it, so that they meet at a point called a focus. The crystalline lens converges the rays of light which enter the eye, and brings them to a focus on the retina. The healthy lens has a power of changing its convexity so as to adapt itself to near and to distant objects.

The Use of the Crystalline Lens

A convex lens, bends the ray of light which pass through it, so that they meet at a point called a focus.…

Meibomian glands (glandulae tarsales), which are sebaceous glands embedded in grooves in the inner surface of the tarsal plates, about 30 in the upper eyelid, less in the lower one. Their ducts open on the inner edge of the free margin of the lids by minute foramina, through which their secretion is furnished to prevent the lids adhering to each other.

Meibomian Glands

Meibomian glands (glandulae tarsales), which are sebaceous glands embedded in grooves in the inner surface…

Muscles of the eyelids, the elevator passing back into the orbit; the sphincter, or orbicular muscle surrounding the eye.

Eyelid, Muscles of

Muscles of the eyelids, the elevator passing back into the orbit; the sphincter, or orbicular muscle…

The muscles of the eyeball, the view being taken from the outer side of the right orbit.

Eye Muscles

The muscles of the eyeball, the view being taken from the outer side of the right orbit.

1, cartilage of the upper eyelid; 2, its lower border, showing the openings of the Meibomian glands; 3, the cartilage of the lower eyelids, also showing its border the openings of the Meibomian glands; 4, 5, the lachrymal glands; 6, its ducts; 7, the plica semilunaris; 8, the caruneula lachrymal canals; 10,11, the superior and inferior lachrymal canals; 12, the lachrymal sac; 13, the nasal duct, terminating at 14 in the lower meatus of the nose.

Eye Muscles

1, cartilage of the upper eyelid; 2, its lower border, showing the openings of the Meibomian glands;…

"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…

The lenses and humors of the eye must be very exactly arranged, in order that the sight may be perfect. They must be so arranged that the images of the objects shall be formed distinctly on the retina. In nearsighted persons the lenses and humors are so arranged as to make the rays that form the images from together too quickly, before they reach the retina, as shown in the figure.

Nearsighted Vision

The lenses and humors of the eye must be very exactly arranged, in order that the sight may be perfect.…

A distribution of the fifth pair of nerves. Labels: 1, The orbit for the eye. 2, The upper jaw. 3, The tongue. 4, The lower jaw. 5, The fifth pair of nerves (trigemini). 6, The first branch of this nerves that passes to the eye. 9, 10, 11, 12, 13, 14, Division of this branch. 8, The third branch that is distributed to the tongue and teeth of the lower jaw. 23, The division of this branch (gustatory). 24, The division that is distributed to the teeth of the lower jaw.

The Fifth Pair of Nerves

A distribution of the fifth pair of nerves. Labels: 1, The orbit for the eye. 2, The upper jaw. 3, The…

An instrument for observing the interior of the eye.

Ophthalmoscope

An instrument for observing the interior of the eye.

The optic chiasma or commissure, which is seen at the base of the brain in front of the tuber cinereum and behind the lamina cinerea. It contains 4 sets of fibers.

The Optic Chiasma

The optic chiasma or commissure, which is seen at the base of the brain in front of the tuber cinereum…

Diagram of the central connection of the optic nerve and optic tract.

Optic Nerve

Diagram of the central connection of the optic nerve and optic tract.

The terminal portion of the optic nerve and its entrance into the eyeball, in horizontal section.

Optic Nerve

The terminal portion of the optic nerve and its entrance into the eyeball, in horizontal section.

Diagram of the central connections of the optic nerve and optic tract.

Optic Nerve and Optic Tract

Diagram of the central connections of the optic nerve and optic tract.

Diagram of the roots of the optic nerve.

Roots of the Optic Nerve

Diagram of the roots of the optic nerve.

View of the second pair of optic nerves.

Optic Nerves

View of the second pair of optic nerves.

Diagram to show the action of the orbital muscle. The arrows show the direction of the action of each muscle.

Diagram to Show the Action of the Orbital Muscle

Diagram to show the action of the orbital muscle. The arrows show the direction of the action of each…

The muscles of the orbit from above.

Orbital Muscles from Above

The muscles of the orbit from above.

The muscles of the orbit from without.

Orbital Muscles from Without

The muscles of the orbit from without.

Transverse vertical section through the orbit behind the eyeball to show the arrangement of muscles.

Arrangement of Orbital Muscles

Transverse vertical section through the orbit behind the eyeball to show the arrangement of muscles.

Schematic representation of the nerves which transverse the cavity of the orbit.

Orbital Nerves

Schematic representation of the nerves which transverse the cavity of the orbit.

"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…

Pigment epithelium of human retina (viewed from the surface).

Pigment Epithelium of Retina

Pigment epithelium of human retina (viewed from the surface).

On the left (a) the pupil is wide open (dilated), while on the right (b) the pupil is contracted. The iris regulates the opening and closing of the pupil and it has two sets of fibers, straight and circular. When the pupil is open the circular fibers of the iris are relaxed while the straight ones are open. When the pupil is contracted, the straight fibers of the iris are relaxed while the circular ones are contracted.

Pupil Contraction and Dilation

On the left (a) the pupil is wide open (dilated), while on the right (b) the pupil is contracted. The…

The external muscles of the pupil.

External Muscles of the Pupil

The external muscles of the pupil.

Vertical section of the pupil.

Vertical Section of the Pupil

Vertical section of the pupil.

"Showing the attachment of the recti, or straight muscles to the eyeball, also the distribution of arteries upon the outer coat of the eye." — Blaisedell, 1904

Attachment of the recti

"Showing the attachment of the recti, or straight muscles to the eyeball, also the distribution of arteries…

"Diagrammatic section through the eyeball. xx, optic axis; k, nodal point." —Martin, 1917

Retina

"Diagrammatic section through the eyeball. xx, optic axis; k, nodal point." —Martin, 1917

"Diagram illustrating the points at which incident rays meet the retina. xx, optic axis; k, first nodal point; k', second nodal point; b, point where the image of B would be formed, were the eye properly accommodated for it; a, the retinal point where the image of A would be formed." —Martin, 1917

Retina

"Diagram illustrating the points at which incident rays meet the retina. xx, optic axis; k, first nodal…

A diagram showing how an image is formed upon the retina by the crystalline lens.

A Diagram of the Retina and Crystalline Lens

A diagram showing how an image is formed upon the retina by the crystalline lens.

The right retina as it would be seen if the front part of the eyeball with the lens and vitreous humor were removed. The white disk to the right marks the entry of the optic nerve (blind spot); the lines radiating from this are the retinal arteries and veins. The small central dark patch is the yellow spot, the region of most acute vision.

Retina Blind Spot

The right retina as it would be seen if the front part of the eyeball with the lens and vitreous humor…

Diagram showing the sustentacular fibers of the retina fiber basket above the external lumbar membrane; m, nucleus of the fiber; r, base of the fiber.

Sustentacular Fibers of the Retina Fiber Basket

Diagram showing the sustentacular fibers of the retina fiber basket above the external lumbar membrane;…

A flattened shape of the globe of the eye causes farsightedness and an elongated shape of the globe of the eye causes nearsightedness. The diagram illustrates the position of the retina in these conditions. Labels: B, natural sight; G, farsightedness; C, nearsightedness.

The Position of the Retina in Near and Far Sight

A flattened shape of the globe of the eye causes farsightedness and an elongated shape of the globe…

A section through the retina from it anterior inner surface (1) in contact with the hyaloid membrane, to its outer (10) in contact with the choroid. 1, internal limiting membrane; 2, nerve-fiber layer; 3, nerve cell layer; 4, inner molecular layer; 5, inner granular layer; 6, outer molecular layer; 7, outer granular layer; 8, external limiting membrane; 9, rod and cone layer; 10, pigment cell layer.

Section of Retina

A section through the retina from it anterior inner surface (1) in contact with the hyaloid membrane,…

The retina of a human eye stretched out vertical.

Eye Retina

The retina of a human eye stretched out vertical.

Diagram of the retina, aka percipient layer of the eye. 1: inner limiting membrane, which is next to the vitreous humor in the eye cavity; 2: a branch of a divided optic nerve; 3: ganglion cell layer; 4: inner nerve-fiber layer; 5: layer of bipolar ("inner granular") cells; 6: outer layer of nerve-cells; 7: layer of visual (outer granular) cells; 8: outer limiting membrane; 9: long and thing rods and short and broad cones; 10: pigment layer; 11: tangential cells; 12: bipolar cells; 13: amacrine cell; 14: centripetal optic nerve fibers; 15: centrifugal optic nerve fibers; 16: Muller's supporting cells. I, II, III: three areas of nerve cells in the retina.

Eye Retina

Diagram of the retina, aka percipient layer of the eye. 1: inner limiting membrane, which is next to…

Formation of an image in the retina.

Image Formation in the Retina

Formation of an image in the retina.

Section through the macula lutea and fovea centralis of the human retina. Labels: a, fovea; b, descent of the macula towards fovea. The numbers indicate the layers of the retina: 1, membrana limitans interna; 2, optic nerve fibers; 3, layer of ganglionic corpuscles; 4, inner molecular layer; 5, inner nuclear layer; 6, intergranular, internuclear, or outer molecular layer. 7, external nuclear layer; 8, membrana limitans externa; 9, layer of rods and cones; 10, pigment-cell layer.

Layers of the Retina

Section through the macula lutea and fovea centralis of the human retina. Labels: a, fovea; b, descent…

Diagram showing the nervous elements of retina. Labels: 1, nerve fiber to ganglion cell; 2, processes of ganglion cell going outwards; 3, nerve fiber passing direct to granule in inner nuclear layer; 4, process of ganglion cell to granule; 5, fiber from cone-granule breaking up into fibrils which are connected with rods and cone fibrils.

Nervous Elements of the Retina

Diagram showing the nervous elements of retina. Labels: 1, nerve fiber to ganglion cell; 2, processes…

Diagram showing relations of the neurons and sensory epithelium in the retina. labels: E, epithelial layer of nucleated rode and cone cells, rods being directed towards choroid coat of retina; N1, neurons of first series receiving by their dendritic impulses from the rod and cone cells and transmitting them by their axons to N2, the neurons of the second series. The axons of the neurons of the second series pass along the inner surface of the retina to the blind spot, where they unite to form the optic nerve.

Neurons and Sensory Epithelium in the Retina

Diagram showing relations of the neurons and sensory epithelium in the retina. labels: E, epithelial…

The posterior half of the retina of the left eye, viewed from before; s, the cut edge of the sclerotic coat; ch, the choroid; r, the retina; in the interior at the middle the macula lutea with the depression of the fovea centralis is represented by a slight oval shade; towards the left side the light spot indicates the colliculus or eminence at the entrance of the optic nerve, from the center of which the arteria centralis is seen spreading its branches into the retina, leaving the part occupied by the macula comparatively free.

Posterior Half of the Retina

The posterior half of the retina of the left eye, viewed from before; s, the cut edge of the sclerotic…

Diagrammatic section of the human retina.

Section of Retina

Diagrammatic section of the human retina.

Structure of the human retina, showing the various layers.

Structure of the Retina

Structure of the human retina, showing the various layers.

Next to the choroid and comprising about 1/4 the entire thickness of the retina is a multitude of transparent, colorless, microscopic rods (a) evenly arranged and packed side by side, like the seeds in the disk of a sunflower. Among them at regular intervals, are interspersed the cones (b). Delicate nerve fibers pass from the ends of the rods and cones, each expanding into a granular body (c) thence weaving a mesh (d) and again expanding into the granules (f). Last is a layer of fine nerve fibers (g) and gray, ganglionic cells (h) like the gray matter of the brain, whence filaments extend into the fibers of the optic nerve (i).

The Structure of the Retina

Next to the choroid and comprising about 1/4 the entire thickness of the retina is a multitude of transparent,…

A section of the retina, choroid, and part of the sclerotic. Labels: a, membrana limitans interna; b, nerve-fiber later traversed by Muller's sustentacular fibers (of the connective-tissue system): c, ganglion-cell layer; d, molecular layer; e, internal nuclear layer; f, internuclear layer; g, external nuclear layer; h, membrana limitans externa, running along the lower part of i, the layer of rods and cones; k, pigment cell layer; lm, internal and external vascular portions of the choroid, the first containing capillaries, the second larger blood-vessels, cut in transverse section; n, sclerotic.

Structure of the Retina

A section of the retina, choroid, and part of the sclerotic. Labels: a, membrana limitans interna; b,…