Sensory impairment Flashcards
Age Related Changes to the Retina
Decreases (↓) in visual acuity in old age may be caused by morphological
changes:
* Choroid
* Pigment epithelium
* Retina
Other causes of ↓ visual acuity
* ↓ function of the rods, cones, and other structures
8 point eye exam includes:
- Visual Acuity
* Acuity (Snellen chart) - Pupillary exam
* Size & shape
* Color (red reflex vs leukocoria)
* Direct & Consensual response - Ocular motility
* Eye alignment
* Corneal light
reflexes - Intraocular Pressure
* Tonometry - Visual fields
- External Exam
* Ptosis
* Growths/lesions
* CN Exams - Slit-lamp examination
- Fundoscopic exam
What does 20/XX mean anyway for vision?
- 20/20 (or 20/40, etc) express visual acuity
- Visual acuity
- Clarity of vision measured at 20 feet * Eg: 20/100 vision
- Patient must stand as close as 20 feet
to see what a person with
normal vision can see at 100 feet
Intraocular Pressure
- Intraocular pressure (IOP) results from intraocular
aqueous fluid production & outflow - IOP ↓ due to ↓ fluid production or loss of globe
integrity - ie. perforating injury
- IOO ↑ when fluid production > outflow
- ie. glaucoma, hyphema
Normal IOP =
10 to 20 mm Hg
Intraocular pressure slowly ↑ with age
Normal eye refraction or “emmetropic”
Parallel light rays from distant objects are in sharp focus on the retina when the ciliary
muscle is completely relaxed.
* However, to focus objects at close range, the eye must contract its ciliary muscle &
thereby provide appropriate degrees of accommodation
What does it mean to be “Farsighted eye or Hyperopia” ?
- Usually the eyeball is too short or, occasionally, the lens system is too weak
- Parallel light rays are not bent sufficiently by the relaxed lens system to come to focus by
the time they reach the retina (capable of focusing distant objects on the retina). - To compensate, the ciliary muscle contracts to ↑ the strength of the lens.
- Objects close-up appear blurry, out of
focus
Presbyopia
Age-related worsening of vision
* Loss of ability to change focus to see objects
that are near
* Atrophy of the ciliary muscle
* Lenses thicken, ↓ elasticity, ↓ flexibility
* Images focus behind retina
What does it mean to have “Nearsightedness or Myopia”?
- Ciliary muscle is relaxed & light from distant objects is focused in FRONT of the retina.
Usually eyeball is too long - Can result from ↑ refractive power in the lens system of the eye.
- The eye cannot ↓ the strength of its lens less than a relaxed ciliary muscle.
- No mechanism to focus distant objects sharply on the retina.
- As an object moves nearer, the eye can focus the image.
Older patients may show an ↑ in ____ caused by changes within the lens
myopia
Concave lens function for eyes
A concave lens is
also known a diverging lens. A
diverging lens is a lens that spreads
out light rays that have been
refracted through it
Convex lens function for eyes
A convex lens is also
known as a converging lens. A
converging lens is a lens that
converges rays of light that are
traveling parallel to its principal axis
Most common cause of reversible blindness worldwide
CATARACTS
CATARACTS etiology
- Most common cause is age-related changes
in crystalline lens - Other causes:
- diabetes mellitus
- galactosemia
- hypocalcemia
- electromagnetic or ionizing radiation
- Trauma (direct penetration, contusion)
- Some medications
Pathophysiology of cataracts
Loss of optical clarity
* Morphological changes
* building up a diffusion barrier to
nucleus coloration/clouding of lens
* Biochemistry
* ↓ glutathione (antioxidant) levels
* formation of advanced glycolated end
products
* loss of alpha-crystallin chaperone
* Physical changes - insolubilisation of
crystallins
Clinical Presentation of cataracts
- Often detected during routine eye
exam in asymptomatic patients - May report gradual painless loss of
vision at distance
Is cataracts bilateral or unilateral?
- Typically bilateral, but can be
asymmetrical
CATARACTS diagnosis
- Most diagnosed during routine ophthalmoscopic exam in asymptomatic patients
- Suspect in older patients with progressive ↓ vision or other S/S
- Diagnosis confirmed by comprehensive eye exam (Ophthalmology)
CATARACTS management
- Management of symptomatic cataract is primarily surgical
- Nonsurgical management
- Prescribe eyeglasses (if appropriate)
- Counsel patients about cataract-related visual symptoms
- Provide reassurance about cause of visual impairment
AGE-RELATED MACULAR
DEGENERATION (AMD)
Progressive chronic retinal disease of
aging eye(s), characterized by:
- Drusen (focal yellowish deposits of
acellular, polymorphous debris)
- Geographic atrophy of retinal pigment
epithelium
- Neovascularization leading to visual
impairment
AMD etiology/pathogenesis
- Cause unknown
- Drusen forms below retinal pigment
epithelium & Bruch’s membrane - Geographic atrophy begins to
manifest as retinal pigment
epithelium changes - Areas of retinal atrophy which may
combine to form larger areas of
depigmentation which coalesce in
central macula → loss of visual
acuity - Chronic inflammatory response
Clinical Presentation of AMD
- ranges from incidental finding to sudden central vision distortion
- May report perceived distortion of objects causing problems with:
- Reading
- Driving
- Facial recognition
- May report ↓ vision, flashes of light (photopsia), or difficulties with light adaptation
AMD diagnosis
- Comprehensive exam, including visual acuity & Amsler grid
- Dilated fundoscopic exam with stereoscopic biomicroscopic exam of the macula
- presence of few medium (63-124 micrometers) Drusen (early AMD)
- retinal hyperpigmentation or hypopigmentation
- retinal atrophy
AMD management
- Smoking cessation (if applicable)
- Early AMD → obervation
- Intermidiate/Advanced AMD → antioxidant vitamin (carotenoids,
vitamins C & E) & mineral supplements (selenium & zinc) - Slows progression of disease J
- Unfortunately, no evidence supports efficacy in early AMD
- 1st Line treatment: Neovascular AMD → Intravitreal injection of antivascular
endotheial growth factor antibodies
Complications & Referral Considerations for AMD
- Blindness
- ↑ risk for depression, hip fracture, & nursing home placement
- Charles Bonnet syndrome
- Visual hallucinations with normal cognition
- ↑ mortality in patients aged 49-75 years
Glaucoma: two types
Acute angle closure: primary glaucoma in which contact of the iris with the peripheral
cornea excludes aqueous humor from the trabecular drainage meshwork.
Chronic open angle: primary glaucoma in which the aqueous humor has free access to the
trabecular meshwork.
GLAUCOMA-ANGLE CLOSURE presentation
- Usually asymptomatic early
- Symptomatic: >90% of attacks are unilateral
- Severe ocular pain
- Sudden vision loss
- Blurred vision
- Halos around lights
- Headache
- Eye redness
- Nausea & vomiting (if IOP high)
GLAUCOMA-ANGLE CLOSURE: PE
- Structural assessment of optic cup
- Visual field loss in severe cases, usually more diffuse with angle-closure Glaucoma
- Tonometry
- Slit-lamp biomicroscopy
GLAUCOMA-ANGLE CLOSURE diagnosis
- ≥ 2 symptoms
1. ocular or periocular pain
2. nausea &/or vomiting
3. Hx of intermittent blurring of
vision w/ haloes - IOP > 21 mm Hg & ≥ 3 signs
1. conjunctival injection
2. corneal epithelial edema
3. mid-dilated unreactive pupil
4. shallow anterior chamber - presence of occludable angle
GLAUCOMA-OPEN ANGLE presentation
Usually asymptomatic early
* Symptomatic
* Ocular burning, smarting, stinging, soreness
* ocular tiredness
* blurry/dim vision
* Eye foreign body sensation
* visual difficulty in daylight &/or darkness
* halos around lights
* Ask about use of steroids
Left untreated it will lead to
permanent blindness
GLAUCOMA-OPEN ANGLE
GLAUCOMA-OPEN ANGLE: PE
Structural assessment of optic cup
* Possible ↓ visual acuity
* Tonometry
* Gonioscopy
* Slit-lamp biomicroscopy
* relative afferent pupillary defect
* tested with swinging light
between eyes
* pupil enlarges when illuminated
while healthy pupil constricts
GLAUCOMA-OPEN ANGLE: Diagnosis
- Presence of progressive optic neuropathy in 1 or both eyes characterized by:
- acquired structural damage to optic nerve
- associated visual dysfunction
- Dx made ophthalmoscopically in setting of an open anterior chamber angle
measured by gonioscopy
GLAUCOMA-ANGLE CLOSURE: Management
→ Ophthalmology
* Asymptomatic angle-closure glaucoma
* Iridotomy (may also be used for Open Angle)
* Bilateral laser iridotomy curative for iris-lens
channel resistance
* Argon laser trabeculoplasty
* Selective laser trbeculoplasty
GLAUCOMA-OPEN ANGLE: Management
→ Ophthalmology
* Long-term medications (↓ IOP) delay visual
progression in pts with primary open-angle
glaucoma or ocular hypertension
* Topical medications
* beta-blockers
* prostaglandin analogs
* parasympathomimetic agents
* alpha-adrenergic agonists
* Systemic carbonic anhydrase inhibitors
DIABETIC RETINOPATHY epidemiology/etiology
- Epidemiology/Etiology
- Microvascular complication of DM
- # 1 cause of preventableblindness in US adults 20-74 yo
- 86% of DM I
- 40% of DM II
- Risk Factors
- African-American, Hispanic, South Asian,
↓ age at Dx of DM, HTN, dyslipidemia, pregnancy, puberty, cataract surgery
1 cause of preventable blindness in US adults 20-74 yo
DIABETIC RETINOPATHY
DIABETIC RETINOPATHY presentation
- Often Asymptomatic!
- Blurred or double vision
- ↓ field of vision
- Seeing dark spots
- Pressure or pain in eyes
- ↓ vision in dim light
- Sudden blindness (rare)
Advanced Hypertensive Retinopathy findings on exam:
- Flame hemorrhages
- Arteriovenous nicking [a small artery
(arteriole) is seen crossing a small vein
(venule), which results in the
compression of the vein with bulging on
either side of the crossing] - Cotton-wool spots
DIABETIC RETINOPATHY diagnosis
- Annual dilated eye examination by ophthalmology or optometry
- Begin assessment
- 5 years after diagnosis of T1D
- At diagnosis of T2D
- More frequent examinations for:
- Pregnant women with DM during pregnancy & 1 year postpartum
- Patients with diagnosed retinopathy
- Patients with macular edema receiving active therapy
____ generally 1st clinical sign in the early-stage of diabetic retinopathy
Microaneurysms
DIABETIC RETINOPATHY management
- Optimize glycemic control, blood pressure, & lipid profile to slow or reduce risk
of progression of retinopathy - Promptly refer patient to ophthalmology for macular edema OR any signs of
diabetic retinopathy - Active Retinopathy → Ophthalmology
- Laser photocoagulation therapy indicated to ↓ risk of vision loss in patients
with DM retinopathy - Vascular endothelial growth factor therapy
Hearing Loss Epidemiology
- Very common
- Wide spectrum
- Nearly undetectable loss ← → profound loss of function & disability
- Affects ~10% of the adult population
- 30-35% of individuals over 65 have hearing loss sufficient for hearing aids
Hearing Loss pathophysiology
Hearing deteriorates with degeneration of hair cells in the organ of Corti, usually after age 50
* But the process begins as early as the 20s
* A network of capillaries (stria vascualris) secrete endolymph to promote the sensitization of hair cells in the cochlea.
* With atrophy, hearing decreases
* Loss of corical & Corti auditory neurons
* ↓ understanding of speech & localization of
sound
* Sensironeuroal hearing loss usually occurs first with `high-frequency sounds & progresses to lower tone
What is sound localization?
- Sound localization refers to a listeners ability to identify the the location of
origin of a detected sound in direction and distance - Loss of directional hearing results in greater hearing difficulty in a noisy
environment. - Localization is disturbed in older adults with hearing loss and may be partly
caused by the aging brain’s deranged processing of interaural intensity
differences and time delays.
Conductive vs. sensorineural hearing
- Conductive hearing: having to do with auditory canal, tympanic membrane, &
the ossicles - In general, lesions in the auricle, external auditory canal, or middle ear
cause conductive hearing loss. - Sensiorneural hearing: having to do with the cochlea & CN VIII
_____ is the most widely
accepted test for hearing loss
Audiogram
Causes of Hearing Loss
cerumen impaction
* exostosis (a benign growth of cartilaginous tissue
on a bone.)
* perforated tympanic membrane
* middle ear effusion
* infection (acute or chronic otitis media
or externa)
* cholesteatoma
* Foreign body in ear canal
* Tympanosclerosis
* Eustachian tube dysfunction
Ototoxic Medications
- Aminoglycoside antibiotics
- Gentamicin, Amikacin, Neomycin, Streptomycin
- Other antibiotics: Vancomycin, Erythromycin
- Antimalarials
- Chloroquine, Quinine
- Platinum-based chemotherapy agents
- Cisplatin, Carboplatin
- Loop diuretics
- Furosemide, Torsemide
- Nonsteroidal anti-inflammatory drugs
- Aspirin, Ketorolac
Taste and aging
- During aging, there is a significant loss
of the ability to taste. - Salivary secretion also diminishes, thus
decreasing solubilization of flavoring
agents. - Upper dentures may cover secondary
taste sites and decrease taste acuity. - Olfactory bulbs also show significant
atrophy with old age - Taste and olfactory changes together
may account for the lessened interest
in food shown by older adults.
POLYNEUROPATHY in the elderly
Patients with polyneuropathy have impairments in balance and an increased
risk for falls and falls causing.
* Diabetes mellitus is the most common risk factor
* Alcoholism, nonalcoholic liver disease, and malignancy.
* In chronic polyneuropathies symptoms usually begin in the lower extremities,
and sensory symptoms usually precede motor symptoms.
Most common risk factor for polyneuropathy
diabetes
POLYNEUROPATHY lab tests
complete blood count, erythrocyte sedimentation rate, thyroid- stimulating hormone, serum and urine protein electrophoresis,
blood glucose, glycohemoglobin, vitamin B12 level, antinuclear antibody,
rheumatoid factor, heavy metals, and HIV, should be directed by the
electrodiagnostic testing results.
Polyneuropathy treatment
- Treatment should address the underlying disease process and alleviation of symptoms.
- Avoidance of toxins, such as alcohol
or drugs, is the most important step. In patients with diabetes, tight control may help maintain nerve function. - In painful neuropathies, tricyclic antidepressants are effective, as
is gabapentin.
In patients with weakness, physical
therapy evaluation is important, and
use of ankle–foot orthosis, splints, and
walking-assistance devices can
improve function. - Proper foot and nail care is important
in reducing risk for foot ulcers.