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Pharmacy Product - Types of eyes -Glossary of Ocular Terms

Eyes

  • Basic Eye Anatomy

Glossary of Ocular Terms

Glossary of Terms for
Anatomy, Physiology & Pathology of the Human Eye

A ,B | C,D,E | F,G,H | I | J,K, L | M,N,O | P,Q,R,S | T,U,V,W | X,Y, Z

I

Inferior oblique muscle
an extraocular muscle in the orbit, originating in the annulus of Zinn; innervated by the oculomotor nerve (cranial nerve III); extorts, elevates, and abducts the eye

Inferior rectus muscle
an extraocular muscle in the orbit, originating in the annulus of Zinn; innervated by the oculomotor nerve (cranial nerve III); depresses, extorts, and adducts the eye

Inflammation
a local response to cellular injury that is marked by capillary dilatation, leukocytic infiltration, redness, heat, pain, swelling, and often loss of function; serves as a mechanism initiating the elimination of noxious agents and of damaged tissue

Inner nuclear layer
layer of the retina containing the cell bodies of horizontal cells, bipolar cells, amacrine cells, and Müller cells

Inner plexiform layer
layer of the retina containing the axons of bipolar cells and amacrine cells and the dendrites of ganglion cells

Internal limiting membrane
the innermost layer of the retina, separating the retina from the vitreous humor

Intracapsular cataract extraction (ICCE)
removal of the entire cataractous crystalline lens, usually by “cryoextraction” (utilization of a cryoprobe whose refrigerated tip adheres to and freezes tissue of the lens, permitting its removal); no longer the preferred method of cataract extraction, having been replaced by extracapsular cataract extraction (ECCE)

Intraocular lens
a small plastic lens, made of a hard plastic (polymethyl methacrylate or PMMA), silicone, acrylic, or hydrogel material, implanted into an eye after cataract surgery to replace crystalline lens which has been removed

Intraocular pressure (IOP)
the pressure within the eyeball that gives it a round firm shape, regulated by the rate at which aqueous humor enters and leaves the eye

Iodopsin
a violet photosensitive pigment found in the retinal cone photoreceptors that is similar to rhodopsin (in rod photoreceptors) but is more labile; contains photopsin (a protein) and retinene (a light absorbing compound which is derived from Vitamin A); important in photopic vision

Iris
the opaque muscular contractile diaphragm that is suspended in the aqueous humor in front of the lens of the eye; perforated by the pupil and continuous peripherally with the ciliary body; possesses a deeply pigmented posterior surface, which excludes the passage of light except through the pupil, and a colored anterior surface which determines the color of the eye

Iris bombe
a condition in which the iris is bowed forward by an accumulation of fluid between the iris and the crystalline lens

Iritis
inflammation of the iris; can be caused by systemic diseases (such as rheumatoid arthritis), systemic infections (such as measles, syphilis, and tuberculosis), trauma, or idiopathic (unknown) sources

Isotonic
having an osmotic pressure equal to that of the surrounding fluid or medium

J

 

Jaw wink
also known as Marcus-Gunn jaw-winking ptosis; a condition in which the upper eyelid will “jump” when chewing or talking; accompanied 35-60% of the time by amblyopia; due to a congenital misdirection of the fifth cranial nerve fibers into a branch of the third cranial nerve that supplies the levator muscle of the eyelid

K

 

Kaposi’s sarcoma
a neoplastic disease especially affecting the skin and mucous membranes, usually characterized by the formation of pink to reddish-brown or bluish tumorous plaques, macules, papules, or nodules, especially on the lower extremities, and formerly limited primarily to elderly men in whom it followed a benign course but now being a major and sometimes fatal disease associated with immunodeficient individuals with AIDS

Keratitis
inflammation of the cornea; includes keratitis sicca, interstitial keratitis, dendritic (branching) keratitis, rosacea keratitis, and neuroparalytic keratitis

Keratoconjunctivitis sicca
a condition associated with reduction in lacrimal secretion and marked by redness of the conjunctiva, itching and burning of the eye, and often filaments of desquamated epithelial cells adhering to the cornea

Keratoconus
progressive thinning of the central cornea, resulting in a bulging outward and the formation of a rounded cone; produces moderate to severe corneal distortion and increase in myopia; can cause corneal scarring, requiring corneal transplantation to restore vision

L

 

Lacrimal layer
aqueous layer; the middle watery layer of the tear film coating the anterior surface of the cornea and “sandwiched” between the lipid (oil) layer above and the mucoid (mucin) layer below; produced by the lacrimal gland, Krause glands, and Wolfring glands

Lamina cribrosa
any of several anatomical structures having the form of a perforated plate, such as the part of the sclera of the eye penetrated by the fibers of the optic nerve

LASIK
laser-assisted in situ keratomileusis; surgical procedure performed to reshape the cornea, in which a microkeratome knife is used to cut a tiny flap in the top of the cornea, underlying corneal tissue is removed with an excimer laser, and the flap is put back into place; used to correct myopia (nearsightedness), hyperopia (farsightedness), and astigmatism

Lateral rectus muscle
an extraocular muscle in the orbit, originating in the annulus of Zinn; innervated by the oculomotor nerve (cranial nerve III); abducts the eye

Leber’s hereditary optic neuropathy (LHON)
a rare hereditary condition which can cause loss of central vision; usually affects men in the late twenties or early thirties; usually affects one eye first, so that central vision is lost in that eye over a period of a few weeks, after which (one or two months later) the second eye is affected in the same way; inherited through a gene which only is passed on through the egg cell from the mother

Legal blindness
blindness as recognized by law which in most states of the U.S. means that the better eye using the best possible methods of correction has a visual acuity of 20/200 or worse or that the visual field is restricted to 20 degrees or less

Lens, crystalline
the biconvex transparent structure located immediately posterior to the iris of the eye which changes shape (flattens and thickens) to focus the incoming light from objects far away and at near; can develop a cloudy, even opaque cataract with age and due to a cumulative absorption of ultraviolet radiation

Lenticular cortex
the portion of the crystalline lens between the outer capsule and the inner nucleus

Lenticular nucleus
the central, most dense portion of the crystalline lens

Limbus
junction between the cornea and the sclera

Lipid layer
oil layer; the thin outer layer of the tear film coating the anterior surface of the cornea, preventing evaporation of the lacrimal layer of the tears; produced by the Meibomian glands and Zeis glands

Lupus erythematosus, discoid
an autoimmune disease characterized by distinct reddened patches covered with grayish brown scales which may appear on the upper cheeks and the nose, on the scalp, the lips, or the lining of the cheeks; lesions on the outsides of the cheeks and on the nose often are in a butterfly pattern

Lupus erythematosus, systemic (SLE)
disseminated lupus erythematosus; an autoimmune disease which may affect any organ or structure of the body, especially the skin, the joints, the kidneys, the heart, the serous membranes (membranes that exude moisture, such as those of the joints or those lining the abdomen), and the lymph nodes; marked by varying acute episodes and remissions, the prospects of survival depending largely on the type and extent of organ involvement; skin lesions may resemble the lesions of discoid lupus erythematosus

Lysozyme
muramidase; a basic bacteriolytic protein that hydrolyzes peptidoglycon and is present in tears and saliva, as well as in egg white

 

 

 

 
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