Sensory Changes with Aging Flashcards
what is refraction
light rays travel into the eye and are bent within the cornea and again in the lens in order to focus light onto the retina
what is accommodation
the lens is able to change shape in order to bend that rays more or less
signal transduction
the retina contains nerve cells (rods and cones) that transform light waves into electrical impulses and send them to the brain for interpretation
what is the lens attached to
the ciliary muscle via connective fibres
what happens when the ciliary muscle is relaxed
fibres get stretched to pull and flatten the lens to focus on objects farther away
what happens when the ciliary muscles contract
the fibres relax to cause the lens to recoil to form a more spherical shape to focus on close objects
what does the lens contain that makes it elastic so it can recoil when the ciliary muscle contracts
collagen
what happens to the lens due to age-related change
gets opaque and stiff
what happens to the cornea due to age-related change
cornea thickens, flattens, and gets rigid
what happens to the retina due to age-related change
decreased density of cells of the neural retina
what happens to the CNS due to age-related change
slower processing of visual stimuli that results in harder to ID objects, especially when moving in and out of light quickly or have a complex figure or background
what is presbyopia
the normal age-related gradual loss of the eye’s ability to focus on close objects
when does presbyopia become noticeable
as early as 40s with progressive worsening with age
what is presbyopia caused by
stiffening of the lens that results in no longer being able to recoil as well when the ciliary muscle contracts
what kind of treatment is there for presbyopia
lens correction like reading glasses or bifocals
what are the pathological conditions of the aging eye
cataracts, glaucoma, age-related macular degeneration, and diabetic retinopathy
what is cataracts
opacity in the lens of the eye due to crystallin misfolds and aggregates making the lens opaque
what is crystallin
a protein found in the lens cells making the lens transparent
what are symptoms of cataracts
decreased acuity, hazy vision, increased sensitivity to glare and harder-to see low-contrast
what is the kind of treatment for cataracts
surgical removal of the lens and replace with prosthetic lens
what is glaucoma
progressive optic nerve damage due to high intraocular pressure
what does glaucoma result in
permanent loss of peripheral vision and blindness if left untreated
what is open-angle glaucoma
slow onset raised intraocular pressure that damages he nerves of the retina and optic nerve
what is closed-angle glaucoma
rapid onset of a sudden blockage of fluid outflow that rapidly elevates intraocular pressure
what symptoms occur with closed-angle glaucoma
severe pain, blurry vision and halos around lights
what kind of treatment is there for glaucoma
eye drops to relieve intraocular pressure
what is macula
the area of the retina where the fovea is located that has a very high density of rods and cones to focus images
what is age-related macular degeneration
loss of central field vision
what are the two types of age-related macular degeneration
dry AMD and wet AMD
what is dry age-related macular degeneration (AMD)
a slow and progressive disease that causes build of lipid deposits in the macula
what are the lipid deposits called in dry AMD
drusen
what is wet age-related macular degeneration (AMD)
dry AMD can progress to wet AMD where there’s a growth of abnormal blood vessels that leak blood and fluid around the macula
what type of age-related macular degeneration is the most common
dry AMD
how to decrease the risk of AMD
exercise, don’t smoke, and good nutrition
what is diabetic retinopathy
damage to blood vessels of the eye due to chronic high blood glucose levels
what occurs in the initial stage of diabetic retinopathy
microaneurysms form but are then absorbed into the retina causing temporary sigh issues like blurriness
what occurs over time with retinopathy
the capillaries of the retina begin to leak fluid onto tissue causing Edema of the retina and prolonged sight issues
what occurs in the late stage of diabetic retinopathy
new blood vessels grow in the retina and easily rupture, bleeding into the eye resulting in blindness
what are symptoms of diabetic retinopathy
range from blurred vision, decreased contrast sensitivity and night vision issues, spotty visual field loss, and complete blindness
what are some treatment options for diabetic retinopathy
control blood glucose levels, laser to treat microaneurysms, or surgically remove scar tissues
how do sound waves enter the ear
reach tympanic membrane causing it to vibrate that is then transferred across 3 small bones of the middle ear that transfer vibrations to fluid waves within the cochlea to push on the flexible membrane in the cochlea at different locations to bend the hair cells that transform the mechanical signal into an electrical signal to be sent to the brain
what is presbycusis
age-related hearing loss
what percent of adults aged 60-79 years old have presbycusis
50%
how does presbycusis manifest
slowly as bilateral loss of high-frequency sounds
what is sensorineural hearing loss
damage and degeneration of sensory hair cells of the cochlea
what is the treatment for presbycusis
hearing aids or cochlear implants
what is tinnitus
perception of sound in the absence of an acoustic stimulus like ringing, buzzing, or whistling
what is tinnitus due to
due to age-related and noise-related damage within the structure of the ear
what can tinnitus be caused by
medications, nicotine, caffeine, high salt, stress, high or low blood pressure
what is central auditory processing disorder
issues processing the neural stimuli like interpretation, recognition, higher-order processing that is linked to neurodegenerative diseases such as dementia
what are some implications of vision loss
activities of daily living become difficult like driving, reading and increased risk of falling
what are some implications of hearing loss
disengagement, isolation, social anxiety and depression are linked to accidents and falls
what can untreated hearing loss be associated with
accelerated cognitive decline and dementia
