Chapter 2: Basic Science (Anatomy of Eye & Common Eye Disorders)
Terms in this set (65)
area inside the eye, behind the cornea, and in front of the iris filled with aqueous humor
A cleary, watery fluid produced by the ciliary body. It fills the front part of the posterior chamber and the entire anterior chamber. It provides nutrients for the lens and posterior cornea and carries away waste products. It is also responsible for maintaining the intraocular pressure because it is the only fluid continually produced in the eye.
Consists primarily of blood vessels that nourish the retina so that it can continue to function. It is sandwiched between sclera and the retina.
The muscle inside of the eyeball that alters the shape of the crystalline lens. It has direct control over the focusing ability of the eye.
the focusing ability of the eye
The clear, cellophane-like tissue that covers the sclera and the inside surface of the eyelids.
lines the eyelids
covers scleral surface of the eyeball
clear, transparent tissue that is located on the very front portion of the eye
the junction of the sclera and the cornea
having no blood vessels
Cornea's 5 Layers
Epithelium, Bowman's Layer, Stroma, Descemet's membrane, and endothelium
Provides focusing power to the eye, It allows adjustment of the eye to focus from distance objects to near objects. It is the second most powerful refractive medium.
six _______ attached to the sclera from the bones surrounding the eye that serve to aim the eyes in the direction we wish to look
bringing the pupil toward the nose
bringing the pupil away from the nose
Only action is adduction; most powerful of the extraocular muscles
Rotate the top of the eye toward the temple and the bottom of the eye toward the nose
Primary action is depression; adduction, extorsion
Only action is abduction
Primary Action is elevation; abduction & intorsion
Primary Action is depression; abduction and intorsion
Primary Action is elevation; adduction & extorsion; only extraocular muscle that has its origin at the front of the orbit
Area in the macula, approximately 1.5 mm in diameter, where visual acuity is the sharpest. The fovea contains the highest number of cones, which are responsible for daytime and color vision.
The bottom or base of an organ, or the part of a hollow organ farthest from its mouth. In eye care, _______ refers to the interior surface of the eyeball.
A ring of muscle tissue that forms the colored portion of the eye around the pupil and controls the size of the pupil opening.
The central part of the retina, which is used for seeing detail. It is an area from 3 to 5 mm in diameter, with the foveal depression at its center.
The adjacent structures of the eye, such as eyelids, lashes, eyebrows, lacrimal apparatus, tarsal plates, orbit, extraocular muscles and conjunctiva.
The portion of the optic nerve that is formed by the meeting of all the retinal nerve fibers. It is insensitive to light and corresponds to the physiological blind spot. The appearance of this structure can be used to determine the healthiness of the nerve itself.
The nerve that carries impulses from the retina to the brain. It transmit the signals from the rods and cones to the brain.
The bony socket the contains the eye and most of its accessory organ. The roof, medial wall and floor are very thin and can be easily damaged by injury, infection, or tumors. For example, a blowout fracture, which occurs in the floor, can be caused by blunt trauma and may cause the eye to appear sunken.
The area located inside of the eye, behind the iris, and in front of the lens.
The round hole in the center of the iris through which light passes. This structure ordinarily appears black because there is very little light coming from the dark chamber behind it.
The seeing part of the eye. This structure lines the sclera and is the place where light coming into the eye is focused. The images that fall on the nerve cells of this structure are then transmitted to the brain, where they are interpreted.
Are the photoreceptors that provide black/white vision, are the most numerous (120 million), and are the most sensitive (night vision, motion detection and peripheral vision)
Are the photoreceptors (6 to 7 million) are responsible for color vision (red, green, and blue _____) and for clear central vision.
The white portion of the eyemade up of a tough, fibrous tissue that gives shape and structure to the eyeball.
Airspaces within the bones. Poor drainage, infection, or cancerous enlargement of these structures may cause headaches, pain around the eye (periorbital), or pain described as coming directly from the eye.
Long, thin fibers which connect the crystalline lens to the ring of ciliary muscles.
A thick, clear, jelly-like substance that fills the eye between the lens and the retina. This fluid serves to support the retina and helps keep the eye round.
The drainage system for tears. As tears are produced by the lacrimal gland, they drain through this structure to reach the surface of the eye.
The gland that supplies most of the tears to the eye. It is located above (superior) and temporal to the eye and behind the orbital rim.
The drainage system for the tears to leave the eye. It is connected to the nasal passage. This why the nose runs when one cries.
Seven Orbital Bones
Maxilla, Lacrimal, Frontal, Palatine, Zygomatic, Sphenoid, Ethmoid
When a cataract progresses to the degree that it interferes with vision, the crystalline lens can be surgically removed. This creates the condition __________ or the absence of a lens in the eye. This can be corrected with strong spectacles or contact lenses.
The most common way to treat cataracts is to replace the crystalline lens surgically with an intraocular lens implant. This creates the condition _______________________, the presence of an intraocular lens after cataract extraction.
Inflammation of the eyelids
As the crystalline lens gets harder with age, it also becomes discolored. A __________ is cloudy or opaque area in the normally transparent lens of the eye.
As the inflammation resolves in a hordeolum, it will sometimes leave a granuloma (small lump). This occurs most commonly when the hordeolum has been recurrent.
Inflammation, also known as "pink eye" or "red eye". This condition can be caused by many things, such as infection from a bacteria, virus or fungus. Allergies also account for many cases of this condition. Symptoms include redness, swelling, and discharge.
Due to poor blood circulation that occurs with diabetes mellitus, new blood vessel growth often develops in the retina. These vessels are relatively fragile and often leak or break. This can lead to scarring, hemorrhages, and retinal detachment, which can lead to permanent vision loss. Diabetes is a major cause of blindness.
A form of strabismus, or squint, in which one or both eyes turn inward. The condition can be constantly present., or occur intermittently, and can give the affected individual a cross-eyed appearance. When the fixating eye is covered, the other eye immediately moves outward. Since both eyes fixate equally well, this would be an alternating esotropia.
these are caused by mechanical simulation of nerves in the retina
caused by debris in the tears and in the fluid inside the eye
condition that damages the optic nerve from increased intraocular
commonly known as a stye, occurs when pores in the eyelid become blocked and inflamed. This essentially is a "pimple" in the eyelid.
condition where the cornea thins and bulges forward
With advancing age, this area often breaks down, leading to a permanent loss of central vision. This is the largest source of irreversible blindness.
A vision condition in which the eyes make repetitive, uncontrolled movements, often resulting in reduced vision. These involuntary eye movements can occur from side to side, up and down, or in a circular pattern. As a result, both eyes are unable to hold steady on objects being viewed.
A thickening of the connective tissue on the sides of the cornea (3 and 9 o'clock). This condition is benign, but may give the patient a slightly yellowish cast to the sides of their eye, or a reddish appearance if the __________________ becomes irritated. Dust, sunlight, wind, and dry air are among the items that may irritate a ______________.
A type of abnormal growth of tissue on the conjunctiva. It is different from the pinguecula in its wedge shape and ability to invade the cornea. Extreme exposure to wind, sunlight and sand are linked to this condition.
The retina pulls away from the rest of the eyeball. Surgical intervention is necessary to reattach the retina and preserve vision. Without surgery, permanent vision loss will occur. Some vision loss will occur with surgery, but early intervention may reduce the amount.
tiny blood vessels between the sclera and conjunctiva occasionally rupture. When the vessel breaks, the blood is trapped under the conjunctiva. This results in a "red eye," which often looks very dramatic.
Canal of Schlemm
a circular _____ lying in the substance of the sclerocorneal junction of the eye and draining the aqueous humor from the anterior chamber into the veins draining the eyeball
an area of tissue in the eye located around the base of the cornea, near the ciliary body, and is responsible for draining the aqueous humor from the eye via the anterior chamber