Ocular Anatomy and Orbit

Flashcards for reviewing key vocabulary related to ocular anatomy and common eye disorders.

Ocular System

Collection of structures including the orbit, eyelids, lacrimal apparatus, extraocular muscles, and eyeball.

Orbit

Surrounds and protects the eyeball, extra-ocular muscles, nerves, and vessels; filled with fatty connective tissue.

Eyelids

Also known as palpebrae; provide shade, protection, and lubrication to the eyes.

Palpebral Fissure

Elliptical opening between the eyelids that expose the eyeball.

Lacrimal Caruncle

Small, reddish elevation containing sebaceous and sweat glands.

Conjunctiva

Mucous membrane lining the eyelids, playing an important role in protecting the eye against microorganisms.

Extra-ocular muscles

Muscles capable of moving the eye in almost any direction; supplied by the oculomotor (III), trochlear (IV), or abducens (VI) nerves.

Connective Tissue Layer of Eye

Outer wall of the eyeball composed of the sclera and cornea.

Sclera

Collagenous, white, tough layer providing structure, support, and protection to the eye.

Cornea

Collagenous, transparent, avascular layer that covers the iris and focuses light into the eye.

Iris

Vascular diaphragm that gives the eye color and controls pupil size.

Ciliary Body

Muscle layer continuous with the iris that controls the shape of the lens.

Choroid

Layer with pigmented and highly vascular layers.

Pupil

Hole in the eye that controls the amount of light entering.

Retina

Tissue that acts like a mirror directing light to the optic disc and processes visual data.

Cones

Cells that see in bright light and enable color vision.

Rods

Cells that see in dim light and enable black and white vision.

Optic Disc

Site where the optic nerve leaves the eyeball.

Macula

Area where the image is projected.

Fovea centralis

Small depression at the center of the macula, contains only cones.

Lens

Hard, transparent, and avascular structure that bends to accommodate light.

Anterior Segment/Cavity

Anterior chamber (cornea to iris) and posterior chamber (iris to lens) filled with aqueous humor.

Aqueous Humor

Transparent watery fluid that nourishes the lens and cornea.

Vitreous Body/Humor

Transparent jelly-like substance that cushions the eye during trauma.

Contact Dermatitis (Eyelid)

Inflammation of eyelid skin caused by contact with a trigger substance.

Stye

Infection commonly found at or near an eyelash follicle.

Chalazion

Inflammation of a blocked oil gland (Meibomian gland).

Xanthelasma

Lipid deposition somewhere near the commissure, painless and yellow.

Dry Eyes

Commonest cause is aqueous tear deficiency. Can be caused by aging, diabetes, drugs or decrease in tear formation.

Watery Eyes

Inappropriate watering of eye that can be due to failure of lacrimal drainage system or overproduction of tears.

Glaucoma

Mixed group of disorders with optic disc damage, visual field loss, and usually raised intraocular pressure (IOP).

Ocular Hypertension

Raised IOP without optic disc damage and visual field loss.

Low/Normal Tension Glaucoma

Glaucoma in absence of high IOP.

Angle Closure Glaucoma

Anatomy of eye predisposes to failure of aqueous humour to pass through pupil preventing aqueous access to trabecular meshwork.

Congenital Glaucoma

Rare, often undetected until advanced. Infant eyeball can be enlarged with elevation of IOP presenting as buphthalmos.

Cataract

Loss of lens clarity associated with age-related degenerative change (senile cataract).