Rehab Head & Face Ch 23 :1 The Eye Kelly Hutchison

Head and Face  The term brain injury may include damage to the scalp, skull, or brain, usually as result of the application of a sudden force to the head.  The head can be divided into two anatomical groups, (the face and the cranium.) 1. The face include the eye, ear, nose, jaw, and mouth  2 The cranium include the brain and spinal cord attachments

The Eye  The eye is protected by:  I. Eyebrow, eyelashes, and eyelids provide physical barriers to objects that might get into the eye  2 Tears produced by nearby lacrimal gland, keep the eye moist, wash away small foreign objects that make it into the eye, and contain an enzyme capable of destroying bacteria  Glands along the border of each eyelid secrete a substance that helps smooth the surface and lubricate the eye. An infection of these glands is called a sty.

Sty Normally warm compresses will heal the sty. Antibiotics may be required if compress does not heal.

EYE  Conjunctiva- thin membrane that covers the eye; cover sclera  Sclera- the white of the eye, thick, fibrous, external coating of the eye. Maintains shape and protects inner structures.  Extrinsic Eye Muscles- responsible for eye movements.  Cornea- clear, transparent in front of sclera. Allows light to pass to inner structures of the eye. It convex shape works with lens to create sharp image on the retina of the eye.

EYE

Eye  Choroid Coat- middle layer of the eye, lines inner sclera, darkly pigmented to prevent random reflections of light entering. Is continuous with the iris.  Iris- the colored muscled layer surrounding pupil.  Pupil- the opening in the iris of the eye that permits the passage of light.  Intrinsic eye muscles – located within the iris, allowing it to change size of pupil and respond to the amount of light available.

Eye

 Lens- a crystal structure that reflects light, transparent, crystalline structure.  Suspensory ligaments- hold lens in place  Ciliary Body- the part of the eye that ligaments that suspend the lens extend. Controls the thickness of the lens.  As the lens increases in thickness, the eye is able to focus nearby objects on the retina.

Eye  Aqueous humor- watery liquid that fills anterior and posterior chambers of the eye.  Vitreous humor-transparent gelatin like substance that fills the greater part of the eyeball. Helps maintain eye shape.

Eye  Retina- innermost layer of the eye; contains rods and cones.  Rods- cells that are sensitive to light. (only one type)  Cones- structures that are responsible for color vision. (3 types sensitive to different ranges of light frequencies allow color vision)  Fovea Centralis- area of the retina rich in cones, where retina is thinnest, providing sharpest vision. The other parts of the retina provide peripheral vision, which is not as sharp.

Eye-  Optic disk- is located where the nerve fibers from rods and cones leave the eye and enter the optic nerve. The optic nerve has no rods or cones ; often referred to as the blind spot.

Corneal abrasion  A scratch or small cut on the cornea of eye.  Occurs when dirt, object scratches eye.  Splash eye with water, do not remove imbedded objects( see Dr.).  Painful; light increases pain.(Patch or sunglasses)  Antibiotic drops help speed healing time

Blows or Contusions  Eye located in deep socket called orbit (boney socket houses the eye).  S/S: pain, swelling &discoloration.  Tx: Apply cold compress x 15 min,and again each hour as needed. See Dr. Id discoloration occurs.

Eye  Cuts, punctures, and abrasions are considered medical emergencies and should consult a physician.

Orbital blow –out fracture  Orbital blow –out fracture consists of fractures of the bones of the eye socket and is usually secondary to blunt blow from large object.  S/S: pain,tenderness, swelling,bruising,double vision (diplopia),protusion of the eye (proptosis),& or numbness in cheek and upper jaw areas.  Tx: Bandage both eyes and apply and ice compress minutes, consult opthamologist.

Hyphema  bleeding into the anterior chamber of the eye, due to bleeding of vessels of the iris.  S/S: Athlete complaining of decreasing vision.  TX: See ophthalmologist; blood is often reabsorbed over a period of days to weeks.

Conjunctivitis  Pinkeye; infection of the conjunctiva.  Can be viral, bacterial, or caused by an allergic reaction.  S/S: Eye discomfort, redness and inflammation of the conjunctiva. White, yellow, greens discharge from eyes may be present  Tx: depends on cause; see physician

Test your blind spot o + One of the most dramatic experiments to perform is the demonstration of the blind spot. The blind spot is the area on the retina without receptors that respond to light. Therefore an image that falls on this region will NOT be seen. It is in this region that the optic nerve exits the eye on its way to the brain. To find your blind spot, look at the image below or draw it on a piece of paper: To draw the blind spot tester on a piece of paper, make a small dot on the left side separated by about 6-8 inches from a small + on the right side. Close your right eye. Hold the image (or place your head from the computer monitor) about 20 inches away. With your left eye, look at the +. Slowly bring the image (or move your head) closer while looking at the +. At a certain distance, the dot will disappear from sight...this is when the dot falls on the blind spot of your retina. Reverse the process. Close your left eye and look at the dot with your right eye. Move the image slowly closer to you and the + should disappear.

 hvision.html for more interesting facts and visual tests. hvision.html