SENSIONEURAL FUNCTION DISORDERS

1. SENSIONEURAL FUNCTION DISORDERS NS 202A Debra Dickinson

2. Impaired Vision • Refractive errors • Vision Impairment & blindness • Promoting coping efforts • Occupational therapy for spatial orientation and mobility • Braille, Print magnification, computer-assisted speech output • Service animals

3. Cataracts • Part of the aging process • Clouding of the eye’s naturally clear lens • Effects approximately 1/2 of Americans ages 65-75 • Normal vision • lights passes through cornea pupil lens • lens focuses light rays on the retina (the layer of light-sensing cells lining the back of the eye) to produce a sharp image of what we see

4. Cataracts • Lens becomes cloudy, light rays cannot pass through it easily • Risk factors • age, diabetes, family history, previous eye injury, medications (corticosteroids), excessive alcohol, excessive sunlight exposure, smoking • some evidence that antioxidant vitamin supplements including vitamin C and E may play role in reducing risk of cataract

5. Cataracts • can develop in one or both eyes and may or may not affect an entire lens • symptoms • Blurred (cloudy) or dimmed vision, poor night vision, sensitivity to light and glare, reduced distance vision, need brighter lighting for reading and other activities, double vision • blinking

6. Treatment of Cataracts • Treatment • Glasses, stronger bifocals, use of magnifying glass, surgery • Surgery allows lens implant brings light rays into proper focus upon the retina • usually outpatient procedure • local anesthesia typical • microsurgery (takes out the cataract but leaves much of eye’s natural lens capsule in place (the capsule helps support an artificial replacement lens that’s inserted)

7. Cataract Surgery • A small opening is made in the front of the capsule that holds the natural lens

8. Cataract Surgery • Ultrasound procedure (phacoemulsification) 3mm incision • the probe dissolves the cataract, allowing it to be gently vacuumed from the eye. • FDA approved use of laser (instead of ultrasound) to dissolve cataract along with the 1/8 inch incision to insert the folded implant.

9. Cataract Surgery • By using soft material that can be folded, the artificial lens (intraocular lens made of inertmaterials) can be inserted inside the eye through the original surgical incision.

10. Cataract Surgery • The lens unfolds to fill the capsule much as the natural lens of the eye had done prior to cataract surgery.

11. Cataracts • Post-op • eye mildly inflamed • feel a little scratchy and irritated for a few days • patient wears a patch for first 24 hours • return visit day after surgery

12. Treatment of Cataracts • Post-op • patch removed at first visit • several more return visits over next 4-6 weeks • wear sunglasses outside • do not rub eye • improvement in vision gradual • Post-op complications • bleeding, swelling, inflammation, infection or retinal detachment

13. Treatment of Cataracts • Post-op • call MD for any of following: • loss of vision, pain not relieved by OTC medication, marked increase in eye redness, light flashes or multiple new spots before your eye, nausea, vomiting or excessive coughing

14. Eye • Optic nerve cells (made up of many nerve fibers) transform the light entering the eye into electrical impulses thatare understood by the brain • Glaucoma • Group of eye diseases all which involve progressive damage to the optic nerve • Leading cause of blindness in world

15. Glaucoma • Clear liquid (aqueous humor) circulates inside front portion of eye. • Small amount of aqueous humor is produced constantly • Equal amount flows out of eye through a microscopic drainage system (maintains a constant level of pressure in the eye) • Aqueous humor is not part of tears on outer surface of eye • Eye is a closed structure • If drainage area (drainage angle) blocked, excess fluid cannot flow out of eye and fluid pressure within eye increases (pushes against optic nerve potentially causing damage • Note: Many people develop glaucoma with “normal” eye pressure

16. Glaucoma • If enough of these cells die, then some vision may be lost • Measuring only the intraocular pressure to diagnose glaucoma has been proven to be wrong • Diagnosis is made by detecting the presence of ocular tissue damage related to intraocular pressure or decrease blood flow to optic nerve

17. Glaucoma • The size of the optic cup is related to the presence or absence of glaucoma • Treatment usually designed to lower intraocular pressure to a level that will no longer damage the optic nerve

18. Most important risk factors of glaucoma • Age over 60 years • Diabetes • African ancestry • Asian or Eskimo ancestry higher risk for angle-closure glaucoma • Family history • Increased intraocular pressure • Previous eye injuries • Nearsightedness • Extensive steroid use

19. Glaucoma • Ophthalmologist evaluation • Tonometry-measures intraocular pressure • Gonioscopy-inspects drainage area of eye; determines type • Opthalmoscopy-examines optic nerve • Optical coherence tomography-imaging technique which shows cross sectional images of retina • Visual field test-tests the peripheral vision of eyes • variety of possible symptoms such as decreased peripheral vision, decreased ability to perceive motion and recognizecolor, etc

20. Types of glaucoma • Chronic open-angle glaucoma • The Canal of Schlemm is somehow clogged, fluid does not drain and pressure builds up • Result is build up of IOP which can damage the optic nerve and lead to vision loss

21. Types of glaucoma • Open-angle glaucoma • most people who develop this form notice no symptoms until vision is impaired • peripheral vision loss • Usually responds well to medications

22. Types of glaucoma • Angle-closure glaucoma • Drainage angle of eye becomes completely blocked. • Iris may drop over and completely close off the drainage angle • Treated with laser or conventional surgery to remove a small portion of the bunched up outer edge of iris. • acute closed angle-closure glaucoma • sudden IOP build up • an emergency because optic nerve damage and vision loss occurs very quickly • nausea, vomiting, rainbow-colored haloes around lights, sudden eye pain, blurred vision, headache

23. Types of Glaucoma • Chronic angle-closure glaucoma • may cause vision damage without symptoms • Both angle-closure and open-angle glaucoma can be primary or secondary.

24. Treatment choices for glaucoma • Medications (eye drops) that decrease aqueous humor production • Prostaglandins-increases outflow of aqueous fluid through uveoscleral route • Xalatan • Beta-blockers-reducesproduction of aqueous humor • Betoptic, betagan, timopotic • Alpha-2 adrenergic agonists-activates receptors in ciliary body, inhibiting aqueous secretion and increasing uveoscleral aqueous outflow. • Alphagan

25. Treatment choices for glaucoma • Medications (eye drops) that decrease aqueous humor production • Carbonic anhydrase inhibitors(drop form; pill form seldom used)-reduces fluid flow into the eye by inhibiting enzyme carbonic anhydrase • Medications (eye drops) that increase outflow of aqueous humor • Miotics-stimulates ciliary muscles, leading to increases in contraction of the iris sphincter muscle(constricts pupil)-seldom used anymore • Pilocarpine • Sympathomimetics-increases rate of fluid flow out of eye and decreases rate of aqueous humor production • Epinephrine

26. Treatment of choices for glaucoma • Surgery • Open-angle (whenmeds no longer work) • selective laser trabeculoplasty-modifiesthedrain thus controlling IOP • Very small burn (opening) made at opening of fluid channel (Schlemm’s canal) • not a cure but helps • Closed-angle • Iridectomy-laser creates hole in iris to improve flow of aqueous fluid to the drainage area

27. Treatment Choices for glaucoma • If trabeculectomy and medications fail, an aqueous shunt may be required. • Glaucoma drainage device (an implant) creates an alternate aqueous pathway

28. Hearing loss in the geriatric population • 1/3 of U. S. adults over 65 (nearly 10 million people) are hearing impaired • Noise-induced hearing loss • Conductive hearing loss • Sensorineural loss is mostly age-related hearing loss results from damage to cochlea or vestibulocochlear nerve

29. Hearing loss • Speech deterioration • Fatigue, Indifference • Social withdrawal, Insecurity • Indecision and procrastination • Suspiciousness, False pride • Loneliness and unhappiness • Tendency to dominate conversations

30. Communication • Chart 64-4 • Hearing impaired with speech difficulty • Hearing impaired and reads speech

31. Aural Rehabilitation • Speech (lip) reading • Listening skills • Speech training • Implanted Hearing Devices • Hearing Guide Dogs • Hearing Aids

32. Hearing Aids • Basic styles of hearing aids • behind-the –ear • in-the-ear • in-the canal • completely-in-the-canal

33. Hearing Aids • The digital age • can reprogram hearing aids from distance • requires that hearing aid is interfaced through patient’s home computer attached to modem • software packages temporarily takes control of the modem (costly)

34. Future of hearing aids • Studies looking at regenerating tiny hair cells in the ear • Advanced Electron microscopy and Imagery Center (AEMI) at House Ear Institute doing a lot of research as well as other major centers