Chapter 5 Diseases and Disorders of the Eye and Ear

1. Chapter 5Diseases and Disorders of the Eye and Ear

2. Functioning Organs of Vision • Vision requires: • light stimulus • relay of light/image to the retina • stimulation of rods and cones in the retina • nerve impulses conducted to brain

3. Normal Eye

4. Functioning Organs of Vision (cont’d.) Signs and symptoms that need medical attention: • visual disturbances • unequal pupils or sudden loss of vision • persistent pain • itching or burning in or around the eyes

5. Functioning Organs of Vision (cont’d.) Signs and symptoms that need medical attention • swollen, red eyelids • redness of the eyes • drainage or exudate • lesions/sores • involuntary eye movements

6. Disorders of the Eye Refractive Errors • Hyperopia (Farsightedness) • light focused behind the retina, which impairs near vision • Myopia (Nearsightedness) • light focused in front of the retina, which impairs far vision

7. Disorders of the Eye Refractive Errors • Astigmatism • light focused unevenly onto the retina, which causes blurred areas • Presbyopia • eye cannot focus quickly to accommodate changes in distance

8. Disorders of the Eye (cont’d.) Nystagmus • involuntary, repetitive, rhythmic movements of one or both eyes Strabismus • failure of the eyes to look together in the same direction

9. Disorders of the Eyelid (cont’d.) Conjunctivitis • inflammation of the conjunctiva in one or both eyes • Mucous discharge from the eye • can be caused by viral or bacterial infection • highly contagious • commonly called “pink eye”

10. Disorders of the Globe of the Eye • Cataracts • cloudy area in the lens • opacity blocks light from reaching retina • usually develop slowly • gradual reduction of vision

11. Disorders of the Globe of the Eye (cont’d.) Glaucoma • damage to the optic nerve caused by elevated intraocular pressure • open-angle vs. closed-angle • One of the major cause of blindness • more common after age 60, but can occur at any age • more common with nearsightedness

12. Disorders of the Globe of the Eye (cont’d.) Macular Degeneration • progressive deterioration in retina • may start with mild distortion of central vision and progress to complete loss • usually both eyes are affected • leads to central vision blindness

13. Disorders of the Globe of the Eye (cont’d.) Diabetic Retinopathy • caused by small hemorrhages and newly formed vessels in the retina • decreased visual clarity • usually both eyes are affected • major cause of blindness

14. Disorders of the Globe of the Eye (cont’d.) Retinal Detachment • separation of the retina from the choroid • usually sudden and painless • early symptoms are seeing light flashes and floaters • more common with nearsightedness • results in blindness if untreated

15. Chapter 5Lesson 5.2

16. Functioning Organs of Hearing Hearing requires: • vibratory or sound stimulus • relay of sound/vibration to inner ear • stimulation of tiny hairs in cochlea • nerve impulses conducted to brain

17. Functioning Organs of Hearing (cont’d.) Signs and symptoms that need medical attention: • hearing loss • ear pain or pressure • ringing or buzzing noise (tinnitus) • vertigo or dizziness • nausea and vomiting

18. Disorders of the Ear Disorders of Conduction • impacted cerumen • infective otitis externa • swimmer’s ear • otitis media • otosclerosis

19. Disorders of the Ear (cont’d.) Infective Otitis Externa • Inflammation of external ear canal with signs and symptoms of: • pain, often severe • red, swollen canal • fever • itching • drainage, watery or purulent • hearing loss

20. Disorders of the Ear (cont’d.) Otitis Media • Inflammation of the middle ear with signs and symptoms of: • feeling of fullness or pressure • impaired hearing • pain, often severe • drainage, watery or purulent • fever • nausea and vomiting • dizziness

21. Disorders of the Ear (cont’d.) Otitis Media • Treatment includes: • analgesics for pain relief • decongestants to promote drainage • antibiotics (for suppurative otitis) • myringotomy: surgical removal of the fluid in severe cases

22. Disorders of the Ear (cont’d.) Ménière Disease • chronic disease of the inner ear • syndrome includes: vertigo, tinnitus, progressive hearing loss and sensation of pressure • sudden onset of episodes (vertigo, tinnitus, etc.) • duration of hours to days • treatment is symptomatic relief, not curative

23. Disorders of the Ear (cont’d.) Labyrinthitis • inflammation of labyrinth usually from viral or bacterial infection; can result from meningitis • ruptured tympanic membrane • tear or injury resulting from pressure, untreated middle ear infection, force or trauma

24. Disorders of the Ear (cont’d.) Sensorineural Hearing Loss • nerve impulses not transmitted to the brain due to damage to the cochlea or auditory nerve • hearing loss can result from loud music, industrial noise, nearby explosion, medications, the aging process, and certain other causes • irreversible, so prevention is essential