Chapter 21 Flashcards
Visual acuity test definition
Screening test to detect deficiencies in vision
Irrigation
Washing a body canal with a flowing solution
Visual acuity
Acuteness or sharpness of vision
Refraction
Ability of the eye to bend the parallel light rays coming into it so that they can be focused on the retina
Myopia
(Nearsighted) eyeball is too long from front to back
• Causes light rays to be brought to a focus in front of retina
• Difficulty seeing objects at a distance
• May squint and have HA from eye strain
• Corrective lenses (eyeglasses, contact lenses) or laser surgery can correct the condition:
Allows light rays to come to a focus on the retina
Hyperopia
(Farsighted) Eyeball too short from front to back
• Causes light rays to focus behind the retina
• Difficulty viewing objects at a reading or working distance
• May have blurring, headache, and eye strain while performing closeup tasks
• Corrective lenses can correct the condition: Cause light rays to focus on the retina
Astigmatism
Causes distorted and blurred vision for both near and far objects
• Normal cornea: Round or spherical shape; smooth
• With astigmatism, cornea is curved into an oval shape, which causes light rays to focus on two different points on the retina (instead of one point); results in distorted and blurred vision
• Often occurs with myopia or hyperopia
Presbyopia
Decrease in elasticity of lens
• Usually begins after age 40 years
• Results in a decreased ability to focus clearly on close objects
• Can be corrected with corrective lenses (reading glasses)
Ophthalmologist
Physician specializing in the diagnosis and treatment of diseases and disorders of the eye
.Prescribes ophtalmic and systemic medications
.Performs eye surgery
Optometrist
Licensed primary health care provider who has expertise in measuring visual acuity and prescribing corrective lenses
• Can diagnose and treat disorders and diseases of the eye
• Prescribes ophthalmic medications
• Not a physician; cannot prescribe systemic medications or perform eye surgery
Optician
Professional who interprets and fills prescription for eyeglasses and contact lenses
Eye occluder
Held over eye not being tested
Are green and red lines the most common colors that are found incorrect by color blind people?
Yes
Eye irrigation
Washing eye with flowing solution
Cleansed the eye by washing away
.foreign particles
.ocular discharges
.harmful chemicals
Relieve inflammation though application of heat
Apply an antiseptic solution
Eye instillation
Dropping of a liquid into the lower conjunctival sac
Treats eye infections (with medications)
Soothe a irritated eye
Dilate the pupil
Anesthetize the eye during eye examination or treatment
Medication instilled in eye may come in the form of
Liquid( ophthalmic drops)
Usually dispensed in a flexible bottle with an attached dropper
Ointment
Dispensed in a small metal tube with tip for applying medication
Whats the range a person with normal hearing can hear, normal speech (frequencies, hertz)
Ranges from 300 to 4000 hz (hertz or cycles per second)
Conductive hearing loss
› Results when there is a physical interference with normal conduction of sound waves through the external and middle ear
> Amount of sound reaching inner ear is less than normal
Conductive loss in external ear
Caused by an obstruction of external ear canal
• Impacted cerumen
• External otitis (swimmer’s ear)
• Foreign bodies
• Benign growths (polyps)
Conductive hearing loss in middle ear
> Caused by an obstruction in middle ear
• Serous otitis media (fluid in middle ear)
• Acute otitis media (infection in middle ear)
• Perforated tympanic membrane
• Otosclerosis
• Cause of conductive loss
• Often detected by examining the ear canal with an otoscope
Sensorineural hearing loss (SNHL)
• Results from damage to inner ear or auditory nerve
> Sound is conducted normally through outer and middle ear structures
> Problem with perception of sound waves; results in a hearing deficit
> Causes
• Hereditary factors
• Degenerative changes from the normal aging process (presbycusis)
• Intense noise exposure over period of time
• Ototoxicity caused by certain medications
• Infectious diseases (measles, mumps, meningitis)
Mixed hearing loss
Combination of both conductive and sensorineural loss
Qualitative test?
Tuning forks
Quantitative test?
Audiometry
Whats the lowest and highest frequency in the tuning fork, that fall within the range of normal speech
Use of tuning fork frequency of 512 or 1024 Hz
Weber test
Useful when one ear hears better than the other
> Fork set in vibration
> Base of fork placed on center of patient’s head
> Patient indicates where sound is heard best
> Results of Weber test:
• Normal hearing: Patient hears sounds equally in both ears
• Conductive hearing loss: Patient hears sound better in problem ear
• Sensorineural hearing loss: Patient does not hear the sound as well in problem ear
Rinne test
Compares the duration of sound perception by air conduction with that of bone conduction
> Fork is set in vibration
> Base of fork is placed against bone of mastoid process
> Patient indicates when sound is no longer heard
> Prongs of fork (still vibrating) placed in the air: 1 inch from opening of ear
› Patient indicates when sound is no longer heard
Rinne test results
Normal hearing: Patient hears sound twice as long through air conduction as through bone conduction
> Conductive hearing loss: Patient hears the sound longer by bone conduction than by air conduction
› Sensorineural hearing loss: Sound is reduced; patient also hears sound longer through air conduction than through bone conduction, but not twice as long
Audiometry
Measurement of hearing acuity using an audiometer
> Audiometer: An instrument that quantitatively measures the various frequencies of sound waves
> Provides information on:
• How extensive hearing loss is
• Which frequencies are involved
Tympanometry
Helps determine hearing loss
Not a hearing test
Tympanometer is a ear piece attached to an electric device
Results
• Normal ear: Eardrum exhibits mobility in response to pressure
• Fluid present in middle ear: Eardrum will not move (remains stiff)
› Used to diagnose serous otitis media
• Common cause of temporary hearing loss in children
• Results printed on a graphic readout:
Tympanogram
Ear irrigation
• Washing of the external auditory canal with a flowing solution
• Cleanse external ear canal to remove:
> Cerumen
› Discharge
> Foreign body
• Relieve inflammation by applying antiseptic solution
• Apply heat to ear
.
• Impacted cerumen must be softened before removal
> Instill warm mineral oil or hydrogen peroxide
• Do not perform irrigation if tympanic membrane is perforated
> Could result in severe irritation or infection of middle ear
Ear instillation
• Dropping of a liquid into the external auditory canal
• Performed to:
• Soften impacted cerumen
> Combat infection with antibiotic eardrops
> Relieve pain
• Eardrops: Usually dispensed in a flexible plastic container with an attached dropper
