Brainscape's Knowledge GenomeTM

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


See full index

Optical despensing > unit 2-3 > Flashcards

unit 2-3 Flashcards

1
Q

Myopia

A

Through the crystalline lens, object will focus before the retina (nearsighted) so by the time the object gets to the retina it is blurry
-Minus lens, concave lens (apex to apex)
-Nearsighted so distance objects are blurry

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

Hyperopia

A

Through the crystalline lens, object lands behind the retina (farsightedness)
-Plus lens, convex lens (base to base)

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

Types of astigmatism

A

Corneal
Lenticular; lens is irregular shape
Picture courtesy of MidShoreeye.com
Astigmatism inside a lens

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

With the rule

A

-Steeper axis at 90
-44 x 90 and 43 x 180
-More common in younger patients and myopics eyes

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

Lensometer
thin lines?

A

sphere

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

lensometer
thick lines

A

cylinder

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

measuring for verticle prism

A
  • Strongest Power at 90
  • Center on OC and PD
  • Measure Rx and any Prism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

measuring for horizontal prism

A
  • Centre for PD and OC – without moving the table
  • Neutralize the Rx
  • Determine Prism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Myopic lenses perscriptions

A
  • -0.25 -> -20.00
    and beyond!
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

hyperopia lenses rx

A
  • +0.25 -> +14.00
    and beyond
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

astigmatic lenses rx

A
  • -0.25 -> -6.00
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

types of progressives

A
  • General Progressives
  • Reading focused Progressives
  • Computer focused Progressives
  • Room focused Progressives
  • Task Specific Progressives
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

lens clock

A

used to measure the base curve of the lens
-Black numbers are for convex
-Red numbers are concave

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

lens aligning pliers

A

Help you align any type of lens axis

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

pupilometer

A

Measure the pupil distance (PD) in mm
-Distance – Infinity
-Near – 40cm
-When fitting progressive you ALWAYS want monocular measurement
-Binocular is the distance from center of pupil to the other center of pupil
-Monocular is from the nose to the center of the pupil

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

penlight and ruler

A

-When measuring distant put penlight on top of the head
-When measuring near put penlight underneath chin

17
Q
  • Distometer & Power Wheel
A

Measure the vertex distance from the back surface of the spectacle lens to the cornea through a closed eyelid

18
Q

lensometer

A

used to verify the prescription of eyeglasses

19
Q

what types of lenses can we measure with a manual lensometer

A

Single spherical lenses
Bifocal
Trifocal
Progressive
Contact lens

20
Q

What steps do we take to measure a lens?

A

-Firstly, focus the eyepiece to yourself (have the black lines be clear)

  • Clear black lines
  • Spherical- when black and green lines are all clear
  • Thin lines- (sphere)
  • Thick lines- (cyl)
21
Q

Prentices rule

A

P = cF
c= distance (cm)
F= Power (D)

22
Q

converting from mm to cm

A

divide by 10

23
Q

Proper positioning of the temple bend on the ear

A
  • When this bend is proper it starts just behind the top of the ear.
  • This allows the bent down portion to be parallel with the root of the ear.
24
Q

Lensometer proccess

A
  • Focus the Black Circle lines
  • Place the glasses convex side towards you, temples away on the table. Both lenses rest comfortably on the table
  • Centre lens mires in the lensometer
  • Power Wheel at highest expected + rx
  • Determine Power at correct axis
  • Determine the power at the cylinder axis
  • Dot the lenses with the ink pens
  • Middle dot = optical center
25
Q

Measurments we need to duplicate eyeglasses

A
  • Prescription
  • Pupil Distance
  • Optical centre
  • Boxing system
  • Vertex distance
  • Base curve
  • Lens thickness
  • Pantoscopic tilt
  • Frame wrap
26
Q

boxing system

A
  • A size
  • B size
  • ED measurement
  • Geometric centre
27
Q

wide jaw temple angling wire

A

adjusting the temple for frame tilt
closed temple fold

28
Q

when reading a perscription in minus cylinder form

A

turn the power wheel in the high plus direction, now slowly turn the wheel back in the minus direction

Optical despensing (5 decks)

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