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The delicate membrane by which the back part of the globe of the eye is lined, and in which the fibers of the optic nerve terminate. See Eye.

A connecting band; a frænum; as, the retinacula of the ileocæcal and ileocolic valves.

Of or pertaining to the retina. Retinal purple (Physiol. Chem.), the visual purple.

A translucent variety of serpentine, of a honey yellow or greenish yellow color, having a waxy resinlike luster.

Retinite.

er harmony. -- Accidental colors (Opt.), colors depending on the hypersensibility of the retina of the eye for complementary colors. They are purely subjective sensations of color which often result from the contemplation of actually colored bodies. -- Accidental point (Persp.), the point in which a right line, drawn…

The impression of a vivid sensation retained by the retina of the eye after the cause has been removed; also extended to impressions left of tones, smells, etc.

of the family Typhlopidæ, with rudimentary eyes. -- Blind spot (Anat.), the point in the retina of the eye where the optic nerve enters, and which is insensible to light. -- Blind tooling, in bookbinding and leather work, the indented impression of heated tools, without gilding; -- called also blank tooling, and blin…

The yellowish green pigment in the inner segment of the cones of the retina. See Chromophane.

ring matters, red, green, yellow, etc., present in the inner segments in the cones of the retina, held in solution by fats, and slowly decolorized by light; distinct from the photochemical pigments of the rods of the retina.

the rays of light are all brought accurately and without undue effort to a focus upon the retina; -- opposed to hypermetropia, myopia, an astigmatism.

mber between h and i; l Anterior Aqueous Chamber; m Crystalline Lens; n Vitreous Humor; o Retina; p Yellow spot; q Center of blind spot; r Artery of Retina in center of the Optic Nerve.

The retina. [Poetic]

The connective tissue supporting the framework of the retina of the eye.

A brown, nitrogenous pigment contained in the retinal epithelium; a variety of melanin.

he eyeball or fault of the refractive media, the rays of light come to a focus behind the retina; farsightedness; -- called also hyperopia. Cf. Emmetropia.

ding points in such focus; this may be received on a screen, a photographic plate, or the retina of the eye, and viewed directly by the eye, or with an eyeglass, as in the telescope and microscope; the likeness of an object formed by reflection; as, to see one's image in a mirror. Electrical image. See under Electrical…

ment of a bright object seen upon a dark ground, due to the fact that the portions of the retina around the image are stimulated by the intense light; as when a dark spot on a white ground appears smaller, or a white spot on a dark ground larger, than it really is, esp. when a little out of focus.

. (c) (Naut.) A succession of short cracks in a defective spar. -- Jacob's membrane. See Retina. -- Jacob's staff. (a) A name given to many forms of staff or weapon, especially in the Middle Ages; a pilgrim's staff. [Obs.] Spenser. (b) (Surveying) See under Staff.

A yellow coloring matter, soluble in ether, contained in the small round fat drops in the retinal epithelium cells. It is best obtained from the eyes of frogs.