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Disorders of Vision, Ocular Movement and Hearing

Disorders of Vision, Ocular Movement and Hearing. Dr. Gerrard Uy. Vision. Errors of refraction: Myopia – globe is too long, light rays come to a focal point in front of the retina

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Disorders of Vision, Ocular Movement and Hearing

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  1. Disorders of Vision, Ocular Movement and Hearing Dr. GerrardUy

  2. Vision • Errors of refraction: • Myopia – globe is too long, light rays come to a focal point in front of the retina • Hyperopia - the globe is too short, and hence a converging lens is used to supplement the refractive power of the eye • Astigmatism - corneal surface is not perfectly spherical, necessitating a cylindrical corrective lens • LASIK (laser assisted in situ keratomileusis)-alter the curvature of the cornea

  3. Vision • presbyopia develops as the lens within the eye becomes unable to increase its refractive power to accommodate upon near objects • In middle age – older age • Emmetropic patient must use reading glasses • Hyperopic patient needs bifocals • Myopic patient only need to remove glasses

  4. Transient or Sudden Visual Loss • AmaurosisFugax • transient ischemic attack of the retina • transient monocular blindness • occurs from an embolus that becomes stuck within a retinal arteriole • Optic Neuritis • inflammatory disease of the optic nerve • Sudden blurred or foggy vision • Pain when moving the eye • Most common cause is MS • all patients experience a gradual recovery of vision after a single episode

  5. Chronic Visual Loss • Cataract • clouding of the lens sufficient to reduce vision • Most develop slowly as a result of aging • occurs more rapidly in patients with a history of ocular trauma, uveitis, or diabetes mellitus • detected by noting an impaired red reflex when viewing light reflected from the fundus • only treatment is surgical extraction

  6. Chronic Visual Loss • Glaucoma • slowly progressive, insidious optic neuropathy, usually associated with chronic elevation of intraocular pressure; usually painless • The mechanism whereby raised intraocular pressure injures the optic nerve is not understood • acute angle-closure glaucoma, the eye is red and painful due to abrupt, severe elevation of intraocular pressure

  7. Ocular Movement • Oculomotor Nerve (CN III) • medial, inferior, and superior recti; inferior oblique; levator palpebrae superioris; and the iris sphincter • ptosis, a dilated pupil, and leaves the eye "down and out"

  8. Ocular Movement • Trochlear Nerve (CN IV) • Innervate contralateral Superior Oblique • hypertropia and excyclotorsion • vertical diplopia is also exacerbated by tilting the head toward the side with the muscle palsy, and alleviated by tilting it away

  9. Ocular Movement • Abducens Nerve (CN VI) • Lateral rectus muscle • horizontal diplopia, worse on gaze to the side of the lesion

  10. Disorders of Hearing • conductive hearing losses • lesions in the auricle, external auditory canal, or middle ear, • sensorineural hearing losses • lesions in the inner ear or eighth nerve

  11. Conductive Hearing Loss • obstruction of the external auditory canal by cerumen, debris, and foreign bodies • Otitis externa/interna • swelling of the lining of the canal • atresia or neoplasms of the canal • perforations of the tympanic membrane • disruption of the ossicular chain • Otosclerosis • fluid, scarring, or neoplasms in the middle ear

  12. Conductive Hearing loss • Cholesteatoma • stratified squamous epithelium in the middle ear or mastoid • slowly growing lesion that destroys bone and normal ear tissue • Maybe congenital or acquired • Symptoms: ear discharge or hearing loss

  13. Conductive Hearing loss • Cholesteatoma • perforation of the tympanic membrane filled with cheesy white squamous debris • Surgery is required to remove this destructive process • 55 – 75% may recur

  14. Cholesteatoma

  15. Conductive Hearing Loss • Otosclerosis • Fixation of the stapes • inherited as an autosomal dominant trait • hearing aid or a simple outpatient surgical procedure (stapedectomy)

  16. Sensorineural Hearing Loss • Damage to the hair cells of the organ of Corti may be caused by: • intense noise • viral infections • ototoxic drugs • fractures of the temporal bone • meningitis • cochlear otosclerosis • Ménière's disease, • aging

  17. If age-related abnormality in VISUAL ACUITY is PRESBYOPIA, what is age-associated hearing loss?

  18. Sensorineural Hearing Loss • Presbycusis – • Age-associated hearing loss • most common cause of sensorineural hearing loss in adults • Starts as loss of high frequency sounds • Associated with loss in clarity • Hearing aids • Cochlear implants

  19. Sensorineural Hearing Loss • Ménière's disease • characterized by episodic vertigo, fluctuating sensorineural hearing loss, tinnitus, and aural fullness • distention of the endolymphatic system (endolymphatic hydrops) leading to degeneration of vestibular and cochlear hair cells • low-salt diet, diuretics, GC

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