Transmission Of Light Flashcards
(24 cards)
Which range of light do humans respond to
390-780nm (visible range)
Humans respond to light of 390-780nm as a result of:
The transmission properties of the eye (reflection,absorption,scatter)
The spectral sensitivity of photoreceptors
What does dioptric apparatus do
Transmits + refracts the viable light to focus it on the retina
What does the iris do
It regulates the intensity of light reaching the retina
What kind of eyeball will a myope have
Elongated eyeball
What kind of eyeball will a hyperope have
Eyeball too short or cornea too flat
What wavelength is Uvc light
100-280nm
What wavelength is uvb light
280-315nm
What wavelength is uva light
315-390nm
What wavelength is visible light
390-780nm
Describe the cornea
Provides a protective coating to the eye
Is an optical lens responsible for 70% of refractive power of the eye
Provides a transparent windscreen
What’s the major later of the cornea
Stroma
What is the stroma composed of
Mainly collagen
What light is absorbed by the cornea
Short wavelength UV light <295nm
What light is transmitted by the cornea
UV light >295nm visible and near infrared light
Describe the aqueous humour
Present mainly in anterior chamber of the eye
Provides the lens and cornea with nutrients
Formed continuously by ciliary body
Passes trough the pupil to the anterior chamber
Drains away to the venous system in the anterior chamber through the Schoenberg canal:trabecular meshwork
Intraocular pressure is influenced by rate at which aqueous humour is produced+drained away
Glaucoma
Inc in ocular pressure result in changes in structure of the optic nerve head + effects on the visual field
Iris
Responsible for the pupillary light reflex
Rods and cones function as transducers
Absorption of light in the outer segment causes signalling to 2ndary neutrons through synaptic terminal
OCT - optical coherence tomography
Seeing all layers of the retina in a patients eye
LCA - Leber’s congenital amaurosis
Rapid loss of photoreceptors in childhood or young adulthood leading to blindness
Age-related macular degeneration
Retinal degenerative disease that causes progressive loss of central vision.
Risk inc with age
What will an eye with AMD have
Drusen
Atrophy
Subretinal hemirrhage
What is retinitis pigmentosa
A group of inherited eye diseases causing degeneration of photoreceptor cells in the retina
Occurs progressively from outermost cells to innermost
Tunnel vision
