Block 1 Review TP Flashcards
What’s the optical power of the tear film?
What’s the power of the lens?
What’s the total power of the eye?
48D
20.83
60D
What’s the top most layer of tear film?
Oily
Tear film stability primarily refers to…?
Evaporation rate
Irregularities of the TF over a long period of time improves retinal image quality T/F?
FALSE
Dry eye patients generate higher order aberrations like sphere aberration and ___ about 2.5 times more than healthy eyes
Coma
Cornea has ____ power of the eye
Lenses have ____
2/3
1/3
Anterior corneal asphericity Q value of human cornea is _____
Positive, negative, or zero
Negative
What should eve the Q value required to eliminate corneal spherical aberration?
-0.528
Spherical aberration will increase as anterior corneal curate ACC becomes…
Bigger, flatter, steeper, thinner??
Steeper
If the central corneal thickness CCT gets thicker than normal leads to __________intracellular pressure
Overestimation
Which part of the GRIN crystalline lens of the human eye has the lowest refraction index
Equator, nucleus,
POLE
Refraction in human eye is due to what three things??
Anterior + posterior + GRIN lens
At accommodative state, the refraction of the crystalline lens is….
\
At relaxed state?
- 85D
21. 25D
AA of an eye with far point 1m and near point of 25cm?
3D
Crystalline lens axial thickness increases all throughout life at rate of ____________ per year
13 microns
In trifocals IOL, potential intermediate vision helps you to ____________ better
Watch TV
Extended range of vision IOLs claims to provide good continuous vision and reduce __________
Glare and halo
What is the job description of IRIS?
All the above
Exit pupil of the aperture stop formed on the image space. T/F?
True
Entrance pupil is an erect, _______ image formed in front of actual pupil
Virtual
DoF for the human eye is between 0.5D and _____D
1D
The line connecting the foveola and the fixation point passing through nodal point
Visual axis
The position at which the keratometric axis intercepts the cornea is called ____________
vertex normal
Angle between the pupillary axis and Los is?
Angle lambda
Disadvantage of using ‘working model’ toy train for solving problems of vision science?
Oversimplified
Who was first to develop an average schematic eye?
Listing
Applying simplification of the model eye concept, how many surfaces does Bennett rabbetts model have?
3 surfaces
Which of the 4 purkinjki images forms images real and inverted?
Purkinji 1,2,3,4??
IV
Some corneal topographers and keratometers work based on the principle of______
Purkinji 1
Consider light source at infinity and Roc is 7.93mm. Determine the location of Purkinji image by treating anterior corneal surface as a MIRROR
3.965
Take number and divide by 2
