Pre-release Flashcards
How does light enter the eye?
Through the front of the eye (cornea) through an opening (pupil) between rings of muscle (iris) and hits the lens. the lens then focuses light on a layer at the back of the eye called the retina which contains phtotreceptors cells called rods and cones.
What are cones repsonsible for?
detailed, high light intensity colour vision.
Where are cones mainly found?
at a region of the retina called fovea
What is the fovea?
A part of a larger section of the eye called the Macula. The macula takes up about 10% of our field of vision and it is where our vision is the sharpest.
what is age-related macular degeneration?
A disease that affects older people, usually over 50 years old. It is a gradula accumulation of damage to the macula, and therefore causes a loss of vision in the centre of field of view, where most detail is normally perceived
Patients with AMD, what can’t they do?
drive, read, watch televeison or do anything that requires detailed vision.
What are some other symtoms of AMD?
Charles Bonnet halloucinations
What can Charles Bonnet halloucinations form?
These can be simple unformed flashes of light, colours or shapes or more elaborate formds such as geometrical grids and lattices. Some people with CBS report seeing landscaped gardens or viastas, animals, people or processions of miniture costumed figures wearing hats, or even disembodies faces with staring eyes. The halloucinations are often seen in more vivid detail than real life.
What are the causes of AMD?
there is no known causes, however there may be a genetic element because AMD tends to run in families. Other causes include age, smoking, cardiovascular disease
What are the two forms of AMD?
Wet and dry
What is the difference between wet and dry AMD?
dry (gradual), wet (can be very rapid)
What is the wet form of AMD casued by?
the production of new blood vesseld under the macula in the eye, which are ‘leaky’. The leaky fluid may include blood and tissue fluid, whcih can dmage the photoreceptor cells and cause scarring of the macula. the new capillaries are made to grow by the production of a protein called vascualr endothelial growth factor (VEGF). Peopole with AMD tend to gave much higher levels of this protein than normal.
What is an optoneterist?
A healthcare professional who focuses on the physical mechanisms of the eye. they can carry out basic eye tests such as reading tests using corrective lenses
What is tonometry?
A test to messure the pressure of the fluid in the eye by pressing on the front of the eye, the cornea
What is tropicamide ?
Is a cholinergic anatgonist, which binds to acetylcholine receptors in the muscles of the iris to prevnt them from contracting. this causews the pupil to dilate and therefore tests, such as refraction tests with lenses and reading charts, can be more accurate
How is tropicamide administered?
as drops in the eye
What are some adverse reactions to tropicamide and what are these caused by?
stinging when applied=pain repsonse
blurred vision and sensitivity to light=extended action
What is an opthalmologist?
A medical doctor who specialises in the eye.
How does an angiogram work?
uses an oral or intravenous dye called florescein. this is added to the sytemic circulation and the eye illuminated with a specific wavelength or light. this highlights the blood vessels in the eye and allows a pciture to be taken of these vesseld to see if any are abnormal or ‘leaky’.
What are the tretament options for Dry AMD?
no treatment but glasses may be used to reduce the affects.
What do the treatments of wet AMD aim to do?
To reduce the production of new blood vessels caused by the increase in vascular endothelial growth fcator (VEGF).
These treatments don’t cure AMD, just significantly slow its progression.
What is the treatment ranibizumab do?
This is an antiangiogenic that cna be injected in the eye (about once to every 3 months). the drug is the FAB fragment of a monoclonal antibody that binds to VEGF and prevents it from binding to receptros. It was developed after anticancer antiangiogenics showed promise in treating wet AMD.
How is photodynamic therapy used for wet AMD?
A drug is injected into the bloodstream. very low power lasers are fired at the blood vessels at the back of the eye and this activates the drug, causing the formation of blood clos and sealing leaky vessels, reducing fluid build-up under the retina. this can only be used in specific cases of AMD.
What can a low vision clinic help with?
advice about contrast, lighting, magnification devices and other aids to help with low vision.q
Where are kidney stones mainly formed?
They can develop in one or both kidneys, and they mostly form in the pelvis/calyces or in the ureter.
what is the function of the kidneys?
Excretion (filtration of the blood to remove urea) and osmoregulation (Maintain blood at a constant water concentration despite salt and water intake).
what age do kidney stones mostly affect?
people over the age of 30
