Vision I Flashcards
A CONVEX lens will _____ light while a CONCAVE lens will ______ light.
- Converge
2. Disperse
Fxnl parts of Photoreceptors
Outer:
- Outer segment
- Inner Segment
Inner:
- Nucleus
- Synaptic body
Refractive power is measured in _____.
Diopters
Avg. diameter of a CONE in the retina?
1.5 micrometers
Synaptic Body
Connects with the HORIZONTAL & BIPOLAR Cells
How is Rhodopsin Formed?
Scotopsin + 11-Cis Retinal
Purpose of a tonometer
Used to measure INTRA-OCULAR pressure
Hyperopia
- Farsightedness
- SHORT Eyeball
What happens to Rhodopsin when exposed to light?
It begins to decompose
Refractive Index
The Ratio of the velocity of light in air traveling through a substance
Inner Segment
Contains Organelles
- Especially MITOCHONDRIA
Myopia
- Nearsightedness
- LONG eyeball
Focal point
- The point through which ALL Parallel rays of light will pass
- After passing through each part of the lens
Refractive Power
A measure of how much a LENS bends light waves
1 diopter equals what?
1 meter/ FOCAL length of a lens
In Dark conditions, what is the electro negativity inside the Outer segment? Why?
- -40 mV rather than -75
2. Due to LEAKY channels
B/w Rods and Cones, which one is more sensitive to the DARK?
Rods
Hyperopia can be fixed with what kind of lens?
Con-CAVE Lenses
Canal of Schlemm
Where aqueous fluid flows in from the Ant. Chamber
Outer Segment
Site of light sensitive Photo-Chemicals
Focal length
The distance from the Center of the Lens to the focal point
Max. VA for 2-point sources of light is what?
(Resolving Power)
1.5 - 2 micrometers
Normal Intra-ocular pressure is what?
15 mmHg
Refraction
Bending of light waves at an ANGULATED surface of transparent Material
What catalyzes the rxn from cGMP -> 5’GMP?
cGMP Phosphodiesterase
Refraction Index of Air
1.0
The relationship b/w Depth of focus and pupillary diameter
INVERSELY Proportional
Total refractive power of the eye
59 Diopters
The Aqueous humor is is formed by what?
Ciliary Processes
What happens to objects that are projected onto the retina?
They will be REVERSED and INVERTED
Function of the Iris
Controls the amount of LIGHT entering the eye
Myopia can be fixed with what kind of lens?
Con-VEX lenses
Can light be refracted if striking PERPENDICULAR to the Surface?
No it continues through W/O Bending
Photosensitive pigments in Rods
Rhodopsin
Photosensitive Pigments in Cones
3 different color pigments
- Blue
- Green
- Red
Emmetropia
The NORMAL eye
- Normal Depth of FOCUS
The degree of refraction depends on what?
- The RATIO of the 2 Refractive indices of the 2 transparent media
- The Degree of Angulation b/w the Interface and the entering wave front
Cones are similar to rods except that the Protein portions are what?
Rods
- Use Scotopsin
Cones
- Use OPSIN
Visual Acuity
Measure of the resolving power of the eye
Total Refractive power of the eye
59 Diopters
