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SENSIONEURAL FUNCTION DISORDERS NS 202A Debra Dickinson 1 Impaired Vision • • • • Refractive errors Vision Impairment & blindness Promoting coping efforts Occupational therapy for spatial orientation and mobility • Braille, Print magnification, computerassisted speech output • Service animals 2 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 lightsensing cells lining the back of the eye) to produce a sharp image of what we see 3 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 4 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 5 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) 6 Cataract Surgery • A small opening is made in the front of the capsule that holds the natural lens 7 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. 8 Cataract Surgery • By using soft material that can be folded, the artificial lens (intraocular lens made of inert materials) can be inserted inside the eye through the original surgical incision. 9 Cataract Surgery • The lens unfolds to fill the capsule much as the natural lens of the eye had done prior to cataract surgery. 10 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 11 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 12 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 13 Eye • Optic nerve cells (made up of many nerve fibers) transform the light entering the eye into electrical impulses that are understood by the brain • Glaucoma – Group of eye diseases all which involve progressive damage to the optic nerve – Leading cause of blindness in world 14 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 15 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 16 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 17 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 18 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 recognize color, etc 19 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 20 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 21 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 22 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. 23 Treatment choices for glaucoma • Medications (eye drops) that decrease aqueous humor production – Prostaglandins-increases outflow of aqueous fluid through uveoscleral route • Xalatan – Beta-blockers-reduces production of aqueous humor • Betoptic, betagan, timopotic – Alpha-2 adrenergic agonists- activates receptors in ciliary body, inhibiting aqueous secretion and increasing uveoscleral aqueous outflow. • Alphagan 24 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 25 Treatment of choices for glaucoma • Surgery – Open-angle (when meds no longer work) • selective laser trabeculoplasty-modifies the drain 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 26 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 27 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 28 Hearing loss • • • • • • • Speech deterioration Fatigue, Indifference Social withdrawal, Insecurity Indecision and procrastination Suspiciousness, False pride Loneliness and unhappiness Tendency to dominate conversations 29 Communication • Chart 64-4 • Hearing impaired with speech difficulty • Hearing impaired and reads speech 30 Aural Rehabilitation • • • • • • Speech (lip) reading Listening skills Speech training Implanted Hearing Devices Hearing Guide Dogs Hearing Aids 31 Hearing Aids • Basic styles of hearing aids – behind-the –ear – in-the-ear – in-the canal – completely-in-the-canal 32 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) 33 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 34