RR: Computer Vision Syndrome Flashcards Preview

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Flashcards in RR: Computer Vision Syndrome Deck (35):
1

What are the ocular findings related to computer vision syndrome?

1. Eyestrain/Eye Fatigue
3. Burning Sensations/Irritation
5. Redness/Dry eyes

2

What % of US workers using a computer over 3hrs/day experience CVS (computer vision syndrome)?

90%

3

What are the non-ocular (ergonomic) symptoms associated with CVS?

1. Headache
2. Pain in shoulders/wrist
3. Pain in Neck
4. Pain in back

4

What are the 3 pathophysical causes of CVS?

1. Ocular surface mechanisms
2. Accommodative mechanisms
3. Extraocular mechanisms

5

Prolonged computer (VDT) use causes what 3 accommodative/covergence findings?

1. Less power of accommodation
2. Removal of NPC
3. Deviation of phoria for near vision

6

Patients below the age of 40 who use VDTs lost _____ (more/less) accommodation amps than those who did not.

Lost more accommodation

7

Gur and Ron found a high prevalence of what 3 things a the end of the day, 4 days later?

1. exophoria
2. Convergence insuffiency
3. Low fusional convergence

8

What type of shift do VDTs cause? How much?

myopia, 0.12D

9

Blink rate is decreased further in a dark setting. What % is it reduced?

60%
- more in post-menopausal women

10

What's the normal blink rate?

10-15x a minute

11

T/F: Upper and lower case documents are easier to read than all uppercase.

True

12

What was used to help schoolchildren with myopia that report visual changes after 30 mins of computer usage.

Screen filters

13

Extemely low refresh rates (flicker) can cause what?

epileptic seizures

14

Lower refresh rates means _____ is weaker and blink rates were _____.

- accommodation was weaker
- blink rates were lower

15

What type of lamp is best used to decrease visual asthenopia?

Sodium lamps

16

Where should a computer be placed to reduce symptoms?

35-40 inches

17

How much tilt should a computer screen have?

10-20degrees

18

Studies show a person should take regular work breaks every __ hours.

4 hours

19

One of the most simple and therapeutic modes of therapy are _____.

Lubricating eye drops

20

What are the accommodative symptoms of CVS?

1. AI (Near blur)
2. Accom. Infacility (slow focus from dist/near vice versa)
3. Acc. Spasm (blur at distance after near)
4. Fatigue/Eyestrain (can't sustain near work)

21

What is the basis of CVS?

1. Extended near point demand
2. Poor resolution/contrast
3. dark background of computer screen

22

What happens to accomodation in upgaze?

Decreases

23

How much does accommodation decrease in upgaze at 20', 30' and 60'

20' = reduced by 1.25D
40' (straight ahead) = reduced by 2D
60' (cpu sits 20' up) = reduced by 3D

24

What are the causes of dry eyes at the computer?

1. Decreased blink rate (1/3 of usual)
2. Increased exposure
3. dry office environment

25

What's the normal, reading and computer blink rate?

Normal = 22/min
Reading = 10/min
Computer = 7/min

26

What does a technica american optic offer as a progressive lens design? What does this lens specify?

-enhanced midrange and near lens design(small distance area)
- specifies distance Rx and add power

27

How should the head be positioned when looking at a computer?

Head back, chin tucked, ears shoulder and hips aligned

28

How should the elbows be positioned when looking at a computer?

At sides - slightly more than 90 degree bend

29

How should the eyes be positioned when looking at a computer?

Level with top 1/3 of screen; 18-24in away

30

When working on the computer, how many times should one take a break?

Every 30 mins

31

What are some suggestions to decrease effects of CVS?

- 20-20-20 rule
- Size up
- Sharpen up
- Reduce glare (good lighting)
- Look down (easier to focus)
- Think blink more

32

The asthenopic symptoms of eyestrain and tired eyes from CVS are diagnosed as wht?

Binocular Vision and Accommodative issues

33

It is important to specify what Rx while prescribing the Readables Varilux lens?

Specify computer Rx

34

It is important to specify what Rx while prescribing the Access Sola lens?

Specify near Rx

35

The Shamir Office Occupational lens is best used in what environment? How many powers are there to choose from?

- best in small office environments
- 4 different powers to choose from