| the sitter also structure of the eye include the | eyebrows, eyelashes, lids, and the lacrimal apparatus |
| tears are made of | watery secretions that contain salt, mucus, and a bactericidal enzyme |
| the sclera gives shape to the eye and, | because of its toughness, protects the intraocular structures |
| the cornea is the | central anterior portion of the sclera |
| four basic processes necessary to form an image: | 1. refraction
2. accommodation
3. constriction
4. convergence |
| refraction | the eye is unable to bend light rays so that the rays fall onto the retina |
| accommodation | the eye can focus on objects at various distances it focuses the image of an object on the retina by changing the curvature of the lens |
| constriction | the size of the pupil, which is controlled by the dilator and contractor muscles of the iris’s, regulates the amount of light entering the eye |
| convergence | medial movement of both eyes allows light rays from an object to hit the same point on both retinas |
| distant vision | 20/20 (able to read line 11 of eye chart at a distance of 20 ft) |
| near vision | able to read newspaper print at 14 inches |
| peripheral vision | side vision 90 degrees from central visual axis; upward 50 degrees, downward 70 degrees |
| eye movement | coordinated eye movement bilaterally |
| color perception | able to properly identify colors of major groups: red, blue, and green |
| the most commonly performed examination is the snellen test, which | assesses visual acuity, which the patient is placed 20 feet from the snellen chart and asked to read lines |
| a centralized black dot is used as the point of reference, the patient asked to view the grid, concentrating on | the dot, and report areas of discoloration |
| today the measurement of intraocular pressure (tanometry) is done | most commonly by puffing air onto the surface of the open eye |
| exotropia | a form of strabismus in which one or both eyes form outward, away from the conea |
| esotropia | a form of strabismus in which one or both eyes turn in the direction of the nose |
| hyperopia | condition of farsightedness |
| myopia | condition of nearsidedness |
| congenital blindness | results from various birth defects |
| acquired blindness in adults occurs as a result | of disorders such as diabetic retinopathy, glaucoma, cataracts, retinal degeneration, infections, tumors, and acute trauma |
| laser-assisted in situ keratomileusis (LASIK) is a procedure in which first a norneal flap is folded back and | then an axcimer laser removes some of the internal layers of the cornea |
| commonly called pinkeye, causes of conjunctivitis may be | bacterial or viral infections, allergies, or environmental factors |
| pink eye involved inflammation of the | conjunctiva |
| complaints of dry eye, caused by a variety of ocular disorders, are characterized by decreased tear secretion or increased tear film evaporation | keratoconjuctivits wicca (dry eye) is caused by lacrimal gland dysfunction, usually a result of an autoimmune dysfunction |
| Sjogren syndrome (an autoimmune disorder characterized by deficient fluid production by the lacrimal, salivary, and other glands, resulting in abnormal dryness of the mouth, eyes, and other mucus membranes
medical management: | for dry eye includes artificial tear replacement |
