L
“L” selections in the Glossary of Terms for
Anatomy, Physiology & Pathology of the Human Eye
To see another alphabetized section, click on a letter below:
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
- lacrimal gland
- see gland, lacrimal
- 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
- laser, argon
- see argon laser
- laser, yttrium aluminum garnet (YAG)
- see yttrium aluminum garnet (YAG) laser
- 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 abducens nerve (cranial nerve VI); abducts the eye (turns the front of the eye outward)
- lazy eye
- see amblyopia
- 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
- lens implant
- see intraocular lens
- 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
- limiting membrane, external
- see external limiting membrane
- limiting membrane, internal
- see internal limiting membrane
- ligaments, suspensory
- see zonules of Zinn
- limbus
- junction between the cornea and the sclera
- line, Schwalbe’s
- see Schwalbe’s line
- 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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