Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Preston's OKAP 2016 > Optics > Flashcards

Optics Flashcards

1
Q

Prentice position

A

back surface perpendicular to the visual axis; max bending

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

image jump

image displacement

A

image displacement more bothersome
Round top only good for hyperopia for displacement
Flat top good for jump and myopia for displacement

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

energy for different color of light

A

ROYGBIV (lower to higher)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

SAM

FAP

A

Steep add Minus (if RGP steep than cornea then tear lens is plus lens, then power of RGP need to add more minus)
Flat add Plus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Transverse mag of lens

A

M=U/V=i/o

MUV in and out

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

ultrasound move faster in lens or aqueous

A

lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q 
? prescribe glasses
hyperopia of low level
hyperopia and eso
myopia
astigmatism
amblyopia
A

hyperopia of lower level: no need

the rest: yes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

laser

A

stimulated emission

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

lens material most common

A

CR-39

Trevix good optic also shatter-resistant

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

OCT

A

base on Michelson interferometer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

positive angle kappa

A

visual axis slight temporal to pupillary axis (fovea slightly temporal)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

far point of eye

A

1/sphere of lens + vertex distance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

cold mirror

A

reflect all visible light but infrared

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

index of reflection is defined

A

at 589nm line of sodium light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

reduced schematic eye

A 
cornea to nodal point 5.6 mm
nodal point to retina 17 mm
total length of eye 22.5 mm
index of refraction 1.33
total power is 60D
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

fit soft CL

A

3 touch method: limbus on each side and cornea apex

17
Q

lensmaker’s equation

A

p=(n1-n2)/r

18
Q

normal AC/A ratio

A

3:1 to 5:1

19
Q

excimer laser length
Femtosecond laser
Yag
Rhodopsin

A 
Excimer laser: 193nm; argon-fluoride laser; UV laser; 6.4 eV per photon. (laser need 4 eV to breaker C-C or C-N bond); low tissue penetration; photoablation
Femtosecond laser (eg. intralase): 1053nm infrared range; photodisruption
Yag: 1064nm; photodisruption
Rhodopsin most sensitive to green light 510nm
20
Q

minimize meridonal mag

A
  • lower the cylinder
  • grind cylinder to the back surface
  • change axis more closer to 90 or 180 degree
  • decrease vertex distance
21
Q

with-the-rule astigmatism

against-the-rule

A

WTR: steep at 90 degree/vertical meridian; correcting plus lens placed at 90 degree
ATR: steep 180/horizontal; correcting with plus lens placed at 180/horizontal

22
Q

correct vertical prism effect of glasses

A
  • slab-off: grind more minus or less plus to create base-up prism over reading area
  • reverse slab-off: add base-down to more plus lens
23
Q

Adjusting to new vertex

A

D2=D1+S(D1)^2

s=difference in vertex (in meter)

24
Q

Toric soft CL

A

adjusting for soft toric CL rotation

LARS (left add, right substract)

25
Q

error in post-refractive myopia surgery

A

hyperopic surprise

  • radius error
  • keratometer index error
  • formula error ( 3rd gen Holladay 1, Hoffer Q, SRK/T using A and K to estimate ELP; 4th gen Haigis, Haigis-L do not use K)
26
Q

index of refraction

A

cornea 1.376

aqueous 1.336

27
Q

duochrome test

A

+0.50D between red and green
RAM-GAP
good for color blind patients

28
Q

fitting hard CL

A

0.5D steeper than lower K-reading

29
Q

Photometer

Radiometer

A

P measure eye response to light, unit is lumen
R measures energy or power, unit is power
eye more sensitive to yellow light

30
Q

To make a CL tighter

A

decrease radius/base curve

increase diameter

31
Q

20/20 E is ~9 mm

so how much 20/60

A

9x(60/20)=9x3=~27mm
60 arcmin is 1 degree
20/20 is 5 arc at 20feet

32
Q

newborn

A

3D hyperopia, then 1 year old , 1D

then 1st decade eye longer/myopic change, cornea power decrease/hyperopic change, lens power increase/myopic change

Preston's OKAP 2016 (4 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions