Amblyopia

Question 1

Broadly define amblyopia

Answer 1

A functional loss of vision NOT attributed to pathology.

Question 2

What is the layman’s term for amblyopia?

Answer 2

“lazy eye”

Question 3

Up to what age does amblyopia usually develop?

Answer 3

Up to age 6-8

Question 4

Once amblyopia develops, how long may it persist?

Answer 4

May persist for LIFE once established.

Question 5

Oversimplified mechanism of action for amblyopia:

1. Brain receives ____ image(s)
2. Brain wants ___ image(s)
3. Eye with _____ picture ____
4. Eye with _____ picture ____

Answer 5

Oversimplified mechanism of action for amblyopia:

1. Brain receives TWO image(s)
2. Brain wants ONE clear image(s)
3. Eye with BEST picture WINS
4. Eye with WORST picture TURNS OFF

Question 6

Amblyopia leads to problems with ______ vision

Answer 6

binocular

Question 7

Precise definition of amblyopia

Answer 7

Reduction in VA to 20/30 or worse in one eye or a two line difference between two eyes in the absence of pathology and with best refractive correction.

Question 8

Three main causes of amblyopia

Answer 8

1. Form deprivation
2. Optical defocus/refractive
3. Strabismus
   (4. Any combo of the above)

Question 9

Define form deprivation

Answer 9

Physical obstruction along the line of sight

Question 10

What are three examples of form deprivation

Answer 10

1. Congenital cataracts; congenital ptosis
2. traumatic cataracts
3. Corneal opacities

Question 11

Results of form deprivation

Answer 11

Prevents a clear, sharp image from reaching the retina

Question 12

For form deprivation to cause amblyopia, what age does it usually have to occur by?

Answer 12

Usually occurs before age 8 to cause amblyopia.

Question 13

Degree to which amblyopia develops from form deprivation depends on what two things?

Answer 13

Depends on the

1. time of onset
2. extent of the form deprivation

Question 14

What are the 3 main categories of refractive amblyopia?

Answer 14

1. Anisometropia
2. Meridional
3. Isoametropia

Question 15

Define anisometropia

Answer 15

An unequal refractive error between the two eyes, usually more than 1 diopter difference

Question 16

The TYPE of refractive error effects the ____ of amblyopia.

Answer 16

severity

Question 17

Characteristics of refractive amblyopia:

Myopia OU:

1. Type of refractive amblyopia
2. Can tolerate a ____ amount of aniso w/o reduction in VA
3. Pt will use (both/one) eye(s) at all distances
4. How many diopters is needed for pt to experience an amblyopia?

Answer 17

1. anisometropia
2. large
3. both
   ex. OD -2.50D (see fine at near)
   OS -1.00D (see fine at near and OK at distance)
4. 5.00D

Question 18

Characteristics of refractive amblyopia:

Hyperopia OU:

1. Type of refractive amblyopia
2. Amblyopia will occur _____
3. Pt will use (both/one) eye(s) at all distances
4. How many diopters is needed for pt to experience an amblyopia?

Answer 18

1. anisometropia
2. sooner
3. one eye (with the least plus)
   ex. OD +2.00D (blurry at D & N)
   OS +1.00D (clear at D & N)
4. 1.00D

Question 19

A general rule for amblyopia is that the more severe the ____, the more severe the ____, and the worse the ___.

Answer 19

1. anisometropia
2. ablyopia
3. visual acuity

Question 20

Characteristics of refractive amblyopia:

Uncorrected high astigmatism OU

1. Type of refractive amblyopia
2. Patient’s image will be clear at (distance, near, neither)
3. How many diopters is needed for pt to experience an amblyopia?

Answer 20

1. meridional
2. Neither distance or near will be clear
   ex. OD plo, -3.00 x180 (blurry D & N)
   OS plo, -3.00 x180 (blurry D & N)
3. at least 1.50D to 2.00D of uncorrected astigmatism

Question 21

Define isoametropia

Answer 21

High degrees of ametropia in both eyes, usually 20/40-20/50.

Question 22

Isoametropia usually associated with hyperopia more than ____ diopters and myopia more than ____ diopters in ___ eye(s).

Answer 22

1. 5.00D
2. 8.00D
3. both

ex. OD +6.00D (blurry D & N)
OS +6.50D (blurry D & N)

Question 23

Stabismic amblyopia usually attributed to…

Answer 23

an early onset CONSTANT unilateral strabismus

Question 24

As a result of strabismic amblyopia, what happens to the two images as they are being processed by the brain?

Answer 24

The two images are NOT fused

Too confusing for the brain

Question 25

What does the brain do to reduce the confusion caused by strabismic amblyopia?

Answer 25

The brain will "switch off" one eye

Question 26

Which of the 3 causes of amblyopia is the most common?

Answer 26

Constant eye turn is the most common cause of amblyopia

Question 27

Will an intermittent eye turn lead to amblyopia?

Answer 27

It may lead to a less severe amblyopia or no amblyopia at all

Question 28

Is it important to screen for amblyopia?

Answer 28

Important to diagnose it early in children because it is treatable and preventable especially if detected early

Question 29

``` What are some tests used to diagnose amblyopia? 1. 2. 3. 4. ```

Answer 29

1. Visual acuity; watch your patient carefully 2. Plus lens test 3. Cover test 4. Stereopsis

Question 30

``` When left untreated, amblyopia can result in 1. 2. 3. 4. ```

Answer 30

1. reduced stereopsis 2. occupational exclusions (pilot, police, military, etc) 3. reduced visual performance (driving, eye-hand coordination, etc) 4. Lack of a "reserve" or "backup" eye

Question 31

If children with amblyopia are treated before age __, they may be able to recover most of their vision .

Answer 31

age 5

Question 32

When treating amblyopia _____ alone will improve the VA in about 25% of the patients.

Answer 32

optical correction