L39 and 40: Opthalmic Flashcards
True or False: Blue light has greater frequency but shorter wavelength compared to red light
True
How does frequency change when wavelength increases?
As wavelength increases, frequency decreases
Light is focused onto the ____, where rods detect ___ and cones detect wavelength
retina; light/dark; wavelength
True or False: Green + Red light is detected as yellow light
True
ok
When you look at a distant object, there are nearly parallel rays, which mean the image on your retina is:
Inverted and real
_____: light bounces off of a surface back toward the source
_______: waves are deflected
when they pass through media with
different densities
______: waves flare out as they
pass through a small opening and
bend around obstacles
Reflection
Refraction
Diffraction
True or False: Angle of incidence = angle of reflection
True
A characteristic of waves is their ability to bend
around disruptive obstacles, which is known as ____
diffraction
When does diffraction most notably occur?
When wavelength and barrier are roughly the same size
Why can’t you see around a wall but you can hear around a wall?
Light wavelengths are much smaller than sound waves
True or False: In any medium, light speeds up
False - it slows down
How does the reflective index affect the speed at which light slows down?
The higher the refractive index (𝑛), the more light
slows down (𝑣)
When light moves to a new medium, the slow
down causes the waves to __
bend
When light moves from air to water and back to air, that’s an example of ____
A. diffraction
B. refraction
C. reflection
B. refraction
When light moves from water to air, light slows down and bends _____ normal
When light leaves water and enters air, it speeds up again and bends ____ from normal
A. towards; away
B. away; towards
C. away; away
D. towards; towards
A. towards; away
What is the function of a lens?
Focus light
Your eyes are an example of….
A. divergent lens
B. convergent lens
B. convergent lens
Using convergent lenses, light is refracted and directed to a central __ ___ behind your lens
focal point
Any incident wave of light traveling ____ to the axis of a convergent lens will pass through the focal point
A. perpendicular
B. parallel
B. parallel
Any incident wave of light traveling through a focal point in FRONT of the convergent lens will ___ and travel ___ to the axis upon exiting the lens
refract; parallel
True or False: With Divergent Lenses, light is refracted and directed outward behind the lens
True
True or False: Divergent lenses have a focal point that is in FRONT of the lens
True
Any incident light traveling ____ to a divergent lens will pass through a focal point on the object side of the lens
parallel
Any incident wave of light traveling parallel to the axis of a divergent lens will ___ and travel in line to the ___
focal point
refract; front
True or False: Any incident wave of light traveling to the rear focal point on the way to a divergent lens will
refract and exit the lens parallel to the axis
What type of image forms from a single point of light?
Real and inverted
When you view a NEAR object, the lens is ___ for strong ___ and there are diverging light rays
When you view a DISTANT object, the lens is ___ for weak ____
round; refraction
flat; refraction
_____ (aka: nearsighted): Type of refractive error where close objects appear normal, but distant ones appear blurry
____ (aka: far sighted): Type of refractive error where distant objects can be seen more easily than closer objects
Myopia
Hyperopia
True or False: Myopia in children can lead to elongated eye – “myopic eyeball” – which can be treated with atropine drops
True
Which test measures light sharpness (visual acuity)?
Snellen
20/200 on snellen suggests ____
blindness
True or False: 1 meter = 1 diopter and a Diopter = 1/focal distance
True
f your uncorrected eye is at “61 diopters,” ….
can then treat with an additive __ diopter lens in front of eye
-1.0
True or False: Lenses can be compounded to work with your cornea and eye. Add prescription lens in front to correct.
True
Which type of lenses should be used to treat hyperopia?
Converging
With glasses use, light never emanates from spot but is perceived by an observer as a ___ object in the distance
larger
Which lens is used to treat Myopia?
A. Convergent
B. Divergent
B. Divergent (concave lens)
True or False: When one has myopia, light falls too short from retina
True
- corrected w concave (divergent) lens
Much of the eye’s focusing power initially comes from the ___
cornea
____ is a refractive eye surgery in which a laser is used to make a corneal flap is made, which reshapes inner cornea stromal layers
LASIK
_____: Benign material floating in vitreous humor, which is caused by shredded and aggregated collagen fibers
Muscae volitantes
What can muscae volitantes (floaters) indicate?
- Retinal detachment
- Retinal tear
____: Opacities of clouding of lens, due to age or trauma
Cataracts
True or False: The lens continuously grows
True
Which cells of the lens maintain a monolayer and display static growth?
Epithelial cells maintain a monolayer and display static growth
Which cell layer of the lens continues to grow, expand, and change over course of one’s life?
A. Monolayer
B. Interior lens fibers cells
C. Exterior lens fiber cells
B. Interior lens fibers cells
___ signals may induce differentiation of lens fiber cells
TGF-B
Expression of which two proteins suggests differentiation of lens fiber cells?
Smooth muscle actin and collagen proteins
What is the ultimate treatment for cataracts?
Cataract surgery
Incision in the eye and phacoemulsification of lens are features of ____ surgery
cataract
True or False: Under normal conditions, there is no blood supply to anterior chamber of eye
True
- Fluid flows continuously into/out of ant chamber
Open/Closed-Angle Glaucoma, as well as congenital and normal tension glaucoma can damage the ___ ___, leading to blindness
optic nerve
True or False: Glaucoma is associated with increased flow
False - reduced fluid flow
In open‐angle glaucoma, the fluid passes too ___ through the trabecular meshwork
slowly
True or False: In glaucoma, eye pressure builds up, leading to damaged optic n
True
What changes occur to the trabecular meshwork in glaucoma?
Decreased compliance of ECM, HTM cells, and outflow
Increased stiffness
Gradual loss of peripheral vision suggests ….
glaucoma
How do prostaglandins and cholinergic treat glaucoma?
A. Reduce fluid production
B. Improve flow
B. Improve flow
How do beta-blockers and alpha adrenergic treat glaucoma?
A. Reduce fluid production
B. Improve flow
A. Reduce fluid production
True or False: Carbonic anhydrase inhibitors (oral) reduce fluid production
True
Trabeculoplasty is a ___ treatment for glaucoma while a Trabeculectomy is a ____ treatment
laser; surgery
What is the most common diabetic disease, leading to blindness? What changes to the retinal blood vessel are seen?
Diabetic Retinopathy
- b.v may swell and leak fluid
- new b.v grow on retina surface
