Eyes Flashcards
function of cornea
transparent outer layer at front of eye
function of conjunctiva
protective membrane over cornea - kept moist by tears from tear glands. Tears contain salts, lubricants and antibodies
function of aqueous humour
a watery substance that keeps the eyes shape and nourishes it
function of iris
a pigmented ring of muscle that controls the amount of light entering the eye. the iris dilates or constricts according to dim or bright light.
function of pupil
the opening in middle of the iris that light passes through
function of lens
behind the pupil is the lens. it is crystalline and sypherical
function of suspensory ligaments
hole ciliary muscles on the lens in place
function of ciliary muscles
contract to stretch the lens making it flatter and thinner to focus on distant objects or they relax to allow the lens to be more spherical to refract more light when reading or working at close distance
function of vitreous humour
transparent jelly-like tissue filling the eyeball behind the lens
function of retina
area at the back of the eye with light sensitive cells called rods and cones. rods are sensitive to light and work well in darker conditions whereas cones work well in bright light allowing us view colours
function of optic nerve
the rods and cones sends information from the eye using the optic nerve. The ‘blind spot’ is where the optic nerve exits the eye
function of macula
the functional centre of the retina containing the fovea. With a higher number of cones this gives us “20/20” vision and provides the best colour image
function of tear glands
located above each eyeball, they continuously supply tear fluid that’s wiped across the surface of your eye each time you blink
malfunction and description of cataracts
cloudy patches of protein develop in the lens. causes blurred and misty as they stop light entering the retina.
age related, diabetes, lifestyle choices eg smoking, alcohol can cause cataracts
cataracts affects front eye, knock off effect of back eye
symptoms of cataracts
cloudy or misty vision
colour look faded
poor night vision
treatment of cataracts
surgery - remove and replace the effected lens (using the artificial cure) is only affective cure
malfunction of glaucoma
pressure builds up on optic nerve due to blocked drain channels. mainly genetic but high blood pressure and age are factors. eyesight progressively deteriorates
symptoms of glaucoma
severe eye pain
headaches
nausea
vomiting
blurred vision
rainbow halves around lights
treatment of glaucoma
laser treatment, eye drops and surgery
malfunction and description of age-related macular degeneration (AMD)
painless eye condition of the macula - results in loss of central vision.
linked to smoking, high BP, being overweight, family history of AMP
symptoms of AMD
vision increasingly blurred
difficulty reading
colours appear dull
faces difficult to recognise
straight lines appear wavy
treatment of AMD
-dry AMD - none, but vision aids can help reduce the effects
-wet AMD - regular eye injections and possibly a light treatment called ‘photodynamic therapy’ to stop your vision getting worse
what is dry AMD
build up of a fatty substance called ‘drusen’ at the back of the eyes
what is wet AMD
growth of abnormal blood vessels at the back of the eye
malfunction and description of retinopathy
high blood sugar levels damage tiny capillaries in the retina
they become narrow and leak
can cause blindness
at risk - african or afro-caribbean background, anyone with type 1 or type 2 diabetes, high bp, or high cholesterol
symptoms of retinopathy
worsening blurred or patchy vision
sudden vision loss
floaters in your field of vision
treatment of retinopathy
laser treatment
injections of medication into your eyes
surgery to remove blood or scar tissue from your eyes
care needs and issues for the malfunctions of the eye
General issues:
reading is difficult
can’t drive
might not be able to work
hard to recognise faces
surgery - 6 week recovery - blurred vision for some time
moving around environment is more difficult
general care options
regular eye tests needed
use brighter lighting
learning braille
decorate rooms in colour to aid vision
which are the two malfunctions of the eye that need laser treatment for treatment
glaucoma and retinopathy
