Brainscape's Knowledge GenomeTM

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


See full index

Contact Lens Theory > Week 2 - Objective > Flashcards

Week 2 - Objective Flashcards

1
Q

What are the 6 parts to an objective assessment?

A

1 - Visual acuity
2 - Keratometry
3 - Corneal Topography
4 - Slit lamp assessment
5 - Lens fitting
6 - Observe CLs fit

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

Do we take VAs at the start of the evaluation with the ROOM LIGHTS ON without gls and cls in/on?

A

Yes

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

What do we record when we take VA measurements?

A

-Distance and near VA’s
-binocular
-monocular recording

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

We measure the VAs with and without cls in.T/F

A

True

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

What is keratometry? 2

A

-is the measurement of the corneal apex of the cornea.
-Measures the flattest and steepest curves of the cornea

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

What does a keratometer measure? 4

A
  • the corneal radius of curvature
    -corneal astigmatism
    -the quality of the corneal refracting surface
    -the base curve selection for contact lens (GP + Soft lenses)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

In contact lens fitting,
the keratometer should be used on
every new patient and on rechecks T/F

A

True

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

What is the K measurement?

A

the measurement that parallels the steepest zone of the flattest primary meridian

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

What is the steepest zone in the cornea?

A

the apex of the cornea

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

What unit is used with K readings?

A

Dioptres

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

Dioptric values can be converted to mm to figure out base curve T/F

A

True

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

If the mires are CLEAR BLURRY CLEAR (clear before the blink/blurred right after the blink/clear again) how do the soft contact lenses fit?

A

The lens fits flat, try a steeper fit

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

If the mires are BLURRY CLEAR BLURRY (blurry before the blink/clear right after the blink/blurry again) how do the soft contact lenses fit?

A

The lens fits steep, try a flatter fit

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

What charts are used to measure VAs (distance and near) ? 3

A

Snellen
Digital VA chart
Reading Card

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

What do we make sure we note when we write the VAs down?

A

OD/OS/OU - keep track of the eye being measured

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

When do you move on with the line or stop and record during the VA measurements?

A

When they get the majority of the letters correct

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How do you write the VAs if they dont get the entire row but can read some of the one below or above?

A

For examples

20/40+1 if they got the entire row of the 20/40 and 1 letter of the 20/30

20/20-2 if they got the majority on that row apart from 2 letters.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the 3 types of corneal astigmatism?

A

-‘with the rule’ astigmatism
-‘against the rule’ astigmatism
-oblique astigmatism

19
Q

What is the steepest meridian in with the rule astigmatism ?

A

Vertical Meridian

20
Q

How will a patients prescription reflect they have an with the rule astigmatism?

A
  • rx will have an axis within 30° of the 180 line
    -it will fall within 001 -30 or between 150-180 degrees.
21
Q

In glasses with the rule astigmatism is corrected with a minus cylinder in the horizontal axis. Why?

A

This creates a steeper
horizontal meridian
thereby neutralizing or
balancing the steepness of
the vertical meridian of the eye.

22
Q

What is the steepest meridian in against the rule astigmatism?

A

Horizontal meridian

23
Q

How will a patients prescription reflect they have an against the rule astigmatism? 2

A

-The pxs prescription will reflect this by having an axis
within 30° of 090 line
-The axis will fall somewhere
between 060-120°

24
Q

In glasses against the rule astigmatism is corrected with a minus cylinder in the vertical axis. Why?

A

This creates a steeper
vertical meridian
thereby neutralizing or
balancing the steepness of the horizontal meridian of the eye

25
Q

Where is the steepest curve in oblique astigmatism?

A

outside of the vertical and horizontal meridians

26
Q

What is considered a steep K reading?

A

-Greater than 45 Dioptres

26
Q

How will a patients prescription reflect they have an oblique astigmatism? 2

A

-The px rx will have an axis that is NOT within 30° of 090 or 180
-An oblique meridian falls between 120°-150° and 30°- 60°

27
Q

What is considered a medium K reading?

A

-42.00 - 45.00 Diopters

28
Q

What is considered a flat K reading?

A

-Less than 42.00 Diopters

29
Q

Why would we do a corneal topography?

A

To gain a comprehensive understanding of the shape of the cornea.

30
Q

Different patters in the corneal topography graph can indicate different issues. T/F

A

True
such as pellucid marginal degeneration, keratonconus or kertoglobus

31
Q

What is the purpose of a slit lamp? 3

A

-provide a closer look at the different structures at the front of the eye and inside the eye
-assessing eye health
-ensuring a proper fit for contact lenses

32
Q

What are 5 other contact lens observations that can be done during the objective part of the cls appt?

A
  • HVID (horizontal visible iris diameter)
  • PA / PF (palpebrae aperture/fissure)
  • Lid Eversion
  • Tear Break Up Time
  • Tear Prism
33
Q

What meridian does the + and - represent in a keratometer?

A

+ = horizontal meridian
- = vertical merdian

34
Q

How is the keratometer reading recorded?

A

Horizontal first then Vertical @ the axis
for example
45.00/45.50 @ 090
This is also an example of with the rule astigmatism as the steepest meridian is in the vertical

35
Q

What are the concentric rings on a corneal topography known as?

A

placido disc

36
Q

How would we find the corneal astigmatism when given K readings?

A

find the difference between the two K readings

37
Q

What do we check for during diagnostic lens evaluation once the lens have been placed on the cornea? 3

A

-lens fit
-comfort
-final power verification

38
Q

What do we use the fluorescein (orange) dye for? 2

A

-stain tear film and devitalise tissue
-used to evaluate GP fit

39
Q

Fluorescein (orange) is most commonly used to asses GP fit. What kind od fluorescein can be used to check the fit of soft cl?

A

High molecular weight

40
Q

What is rose bengal (red) staining agent used for? 3

A

-stain devitalized tissue
-Shows deficiency of preocular tear
film protection
-diagnose ocular surface disorders

41
Q

What is lissamine green staining agent used for? 2

A

-Used to stain devitalized tissue.
-Also stain epithelial cells that are
unprotected by mucin or glycocalyx.

42
Q

If the mires are CLEAR CLEAR CLEAR (clear before the blink/clear during the blink/clear again) how do the soft contact lenses fit?

A

good fit

Contact Lens Theory (27 decks)

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