Special senses - opthalmological appearance of the retina Flashcards
What instrument is used to examine the retina and vitreous?
An opthalmoscope
What is an opthalmoscpoe?
A hand held instrument with a battery powered light source. With a series of lenses that can be used to focus the wiev of the retina
What is a direct pothalmoscope useful for?
examination of the retina
Indirect opthalmoscope uses…
magnifzing glasses in front of the patients eze
What are the most obvious features of the retina viewed through an opthalmoscope?
blood vessels on retinal surface
From where doe the retinal blood vessels originate?
from a pale circular region called the optic disc (optic nerve head)
What is the optic disc?
The region where the optic nerve fibres exit the retina
What is the macula?
The part of retina for central vision, distinguished bz the relative abscence of large blood vessels
What are one of the specializations that improve the quality of central vision?
The abscence of large bloodvessels in the macula
What is the fovea?
a dark spot in the centre of macula about 2mm in diameter where the retina is thinner
What is the function of fovea?
The bipolar and ganglion cell layers are pulled aside so light can strike the receptors directly, and the fact that there is onlz cones here makes the fovea the point of the most distinctive vision (colour)
In which metabolic disease can there be observations of changes in the retina?
Diabetes –> diabetic retinopathy
What is a convenient anatomical reference point?
Fovea in the centre of retina
What is a catarct?
clouding of the lens contained in a capsule. Old cells die and become trapped within the capsule –> create cloudyness
What is ARMD?
Age related macular degeneration –> a degenerative condition of the macula
