Hearing and visual impairement

Hearing and visual impairementPrepared byMs. Jyoti kunduVisual impairment

definitionVisual impairment is defined as the limitation of actions and functions of the visual systemThe National Eye Institute defines low vision as a visual impairment not correctable by standard glasses, contact lenses, medication or surgery that interferes with the ability to perform activities of daily living.Classification of visual impairmentLow visual acuity means vision between 20/70 and 20/400 with the best possible correction, or a visual field of 20 degrees or lessBlindness is defined as a visual acuity worse than 20/400 with the best possible correction, or a visual field of 10 degrees or less

Legal blindness in the US means visual acuity of 20/200 or worse with the best possible correction, or a visual field of 20 degrees or less.Visual acuity of 20/70 to 20/400 (inclusive) is considered moderate visual impairment or low vision

Common visual problemHyperopia:- Can see objects farther away but not close one.Eye ball is too short.

Myopia :-Can see objects close away but not fartherEye ball is too long

Astigmatism :-Produces images similar to looking at carnival mirror

Color blindness :-Decrease ability to disntinguish colors.Usually genetic cause but can be caused by nerve damageProblem with cones cellsCausesInjury to the eyesInjury to the eyes while playing or at work or due to accidents may result in vision loss and impairment.Particularly injuries to the cornea are the commonest cause of vision loss.

Inherited conditions of blindness and vision impairmentRetinitis pigmentosa is the most common cause of inherited blindness.

Infections of the eyesSometimes if the mother has had a viral infection like German measles that is transmitted from the mother to the developing fetus during pregnancy the baby may be born with blindness or visual impairment.

Diabetic retinopathyDiabetes affects the small blood vessels in the retina. When damaged this leads to impairment of vision.

GlaucomaThis condition results due to raised pressure within the eyes. The increased pressure impairs vision by damaging the optic nerve.

Age related Macular degenerationAge related Macular degenerationor AMD that is a progressive loss of the visual acuity due to damage to the macula that is the most sensitive part of the retina.The risk of AMD rises in those exposed to excess sunlight and those who smoke excessively.

AmblyopiaThis is basically impaired vision in one eye due to lack of its use in early childhood.

CataractClouding of part or the entire lens of the eye.Normally, the lens is clear to let in the light that focuses on the retina. Cataracts prevent light from easily passing through the lens, and this causes loss of vision.

AIDS related visual impairmentThis is usually caused by viral infections of the eyes called Cytomegalovirus or CMV retinitis.Cancer of the eyes

Retinoblastoma is the most common eye cancer of children. There are between 300 and 400 new cases diagnosed annuallySigns and symptoms Headache with reading and writingLeave small words while readingBlinking of eyeFrustation due to inability to readEyes can be watery and swollenCovering one eye while reading or doing workdiagnosisDiagnosis begins with complete history and family history of visual impairment in the patient.External examination of the eye including lids, conjunctiva, cornea, iris, lens, etc. are the next stepSnellen testThe Snellen test is also known as the visual acuity test.Usually a chart called the Snellens chart is used. It contains progressively shortening random letters and numbers and is placed 6 meters away from the patient.

Visual field testVisual field is the range of vision that a person can see without tilting or turning ones head. This measures the peripheral vision of the eyesTonometry testThis test uses specialized instruments to determine fluid pressure inside the eye to evaluate for glaucomaOcular Motility AssessmentThis tests if there is squint of other problems in the movement of the eyeballs

Treatment Control of diabetes This prevents progression of diabetic retinopathy and resulting visual impairment to some extent. However in advanced cases this may be of little help.Cataract surgery In cases of visual impairment due to cataracts, surgery may be opted. Usually an artificial lens is placed within the eye as a replacement of the damaged and clouded lens. This, more often than not restores vision.Magnification systems This is achieved using appropriate lens, reading telescopes or surgical systems etc. Hand magnifiers may also be offered. For improvement of visual fields prisms and mirror systems may be prescribed.

Glaucoma medications in eye drops are prescribed to control glaucoma. These may contain drugs like Latanoprost, tafluprost, travoprost which are prostaglandin analogues.The drugs may include Beta-blockers like betaxolol hydrochloride or carbonic anhydrase inhibitors dorzolamide and Sympathomimetics like brimonidine tartrate.Glaucoma may also be managed surgically using open microscopic surgery, laser corrections, etc.At present there are no cures forage-related macular degeneration(AMD) especially of the dry variety.

Hearing impairement

Definition A person suffering from hearing impairment has difficulty in perceiving or identifying sound clearly due to auditory problems

Classification :- Degree of Hearing Loss Ability to perceive soundMild -Difficult to identify soft sound such as whisperingModerate -Unable to hear clearly what others are saying during conversation. Hearing aids are necessary.Moderately-severe -Unable to clearly hear loud noises such as telephone ringSevere- Can only hear very loud noises and sounds such as shouting or vacuum cleaner noiseTypes of hearing loss :-There are four types of hearing loss:Auditory Processing DisordersConductiveSensorineuralMixedAuditory Processing DisordersAuditory Processing Disordersoccur when the brain has problems processing the information contained in sound, such as understanding speech and working out where sounds are coming from.

Conductive Hearing LossConductive Hearing Loss occurs when there is a problem with theOuterorMiddle Earwhich interferes with the passing sound to theInner Ear.

Sensorineural Hearing LossSensorineural Hearing Loss occurs when the hearing organ, the Cochlea, and/or the auditory nerve is damaged or malfunctions so it is unable to accurately send the electrical information to the brain. Sensorineural Hearing Loss is almost always permanent.

Mixed Hearing LossA Mixed Hearing Loss occurs when both Conductive Hearing Loss and Sensorineural Hearing Loss are present. The sensorineural component is permanent, while the conductive component can either be permanent or temporary

causesCongenital factors Heredity Viral infection during pregnancy, e.g.rubella infection Congenital defects such as anomalies of the ear, nose or throat Premature birth, birth asphyxia,excessive bilirubin, etcAcquired factorsExcessive earwax Eardrum perforation Middle ear effusion or infection Otosclerosis or ear ossicle dislocation Sequelae of childhood diseases such as measles and meningitis Head or ear trauma Prolonged exposure to loud noise Medication that may lead to hearing damage

symptomsEarly signs of hearing loss can include:difficulty hearing other people clearly and misunderstanding what they say, especially in group situationsaskingpeople to repeat themselveslistening to music or watching television with the volume higher than other people needdifficulty hearing the telephone or doorbell

finding it difficult to tell which direction noise is coming fromregularly feeling tired or stressed,from having to concentrate while listening

During infancy:1-3 months old No response to sudden sound such as banging of door or ringing of doorbell.4-6 months old Unable to locate the sound source.7-9 months old Do not look at the person being mentioned, e.g. Where is UncleTom?.10-12 months old No response to their names being called or frequently used words or phrases, e.g. No.During childhood: Delayed response to soundCannot hear clearly what others are saying Show difficulty in locating the sound source Pay more than usual attention to speakers facial expression and lip movement whilelistening Give irrelevant answers or misinterpret instructions Request for repetition during conversation Show poorer ability to understand speech ` in a noisy environment Tend to turn up the sound volume of television Incorrect pronunciation Delayed language development Poor attention in class Frequent use of gestures to express themselves, e.g. pointing to what they want Easily irritated as a result of communication difficulty

Diagnosis Physical exam.Your doctor will look in your ear for possible causes of your hearing loss, such as earwax or inflammation from an infection. Your doctor will also look for any structural causes of your hearing problems.General screening tests.Your doctor may ask you to cover one ear at a time to see how well you hear words spoken at various volumes and how you respond to other sounds.

Tuning fork tests.Tuning forks are two-pronged, metal instruments that produce sounds when struck.

Audiometer tests.During these more-thorough tests conducted by an audiologist, you wear earphones and hear sounds directed to one ear at a time. The audiologist presents a range of sounds of various tones and asks you to indicate each time you hear the sound

Treatment Removing wax blockage.Earwax blockage is a reversible cause of hearing loss..Surgical procedures Surgery may be necessary if you've had a traumatic ear injury or repeated infections that require the insertion of small tubes that help the ears drain.Hearing aids.If your hearing loss is due to damage to your inner ear, a hearing aid can help by making sounds stronger and easier for you to hear. Cochlear implants.If you have severe hearing loss, a cochlear implant may be an option for you.