Introduction to Amblyopia Flashcards
“Lazy eye” is also known as what?
Amblyopia.
True or False: Amblyopia is the functional loss of vision attributable to pathology.
False. Not attributable to pathology.
What age does amblyopia usually develop?
Age 6-8 and may persist for life once established.
In an amblyopic eye, brain receives 2 images, one clear and one blurred. This is also known as what? What mechanism occurs afterwards?
Anisometropia. Brain wants one clear image so the eye with the best picture wins and the the eye with worst picture turns off.
What three problems does amblyopia cause with binocular vision? What other problem does amblyopia cause?
Poor eye tracking, poor accommodative response, and suppression of one eye. Also loss of depth perception (3-D)
True or False: Amblyopia is a reduction in VA to 20/30 or worse in one eye or a two line difference between the two eyes.
True.
True or False: For amblyopia to exist, the visual pathway does not develop normally because of inadequate stimulation.
True.
Amblyopia is a major cause of loss in vision in what age group?
Under 45 year age group.
Amblyopia affect approximately what percention of the population in the US?
2%.
What are some causes of amblyopia? (Name 4).
Form deprivation, optical defocus (anisometropia, meridional, isoametropia which is equal but large refractive error), strabismus or eye turn.
Physical obstruction along the line of sight is called what? Name some examples of this.
Form deprivation. Congenital cataracts; congenital ptosis; Traumatic cataracts; Corneal opacities.
When does form deprivation usually occur?
Before age of 8 to cause amblyopia.
The degree to which amblyopia develops depends on what?
The time of onset and the extent of the form deprivation.
True or False: Form deprivation allows for clear, sharp images to reach the retina.
False. Prevents a clear, sharp image from reaching the retina.
Refractive amblyopia (or optical defocus) has three main categories. What are they?
Anisometropic, meridional, and isoametropic.
What is defined as an unequal refractive error between the two eyes, usually more than 1.00D difference?
Anisometropic refractive amblyopia.
Which refractive problem can tolerate a larger amount of anisometropia without a reduction in the VA?
Myopia OU.
True or False: Myopic patients may not have as severe an amblyopia even with 5.00D of anisometropia.
True.
Amblyopia will occur sooner in which refractive condition?
Hyperopia OU.
True or False: Hyperopic patients will not demonstrate amblyopia with just 1.00D of anisometropia.
False. Patient may demonstrate amblyopia with even 1.00D of anisometropia.
A general rule for amblyopia is that the more severe the ___________, the more severe the ___________, and the worse the __________.
Anisometropia, amblyopia, visual acuity.
Uncorrected high astigmatism OU is referred to as what?
Meridional refractive amblyopia.
Amblyopia will not usually occur until there is at least ____D to ___D of uncorrected astigmatism.
1.50, 2.00D.
High degrees of ametropia in both eyes is referred to as what?
Isoametropic refractive amblyopia.
Isoametropia is assoicated with hyperopia more than _____D and myopia more than _____D in both eyes.
5.00, 8.00D.
True or False: Strabismic amblyopia may combine with anisometropia to cause a greater reduction in VA.
True.
What is being described?
OD -2.50D (see fine at near)
OS -1.00D (see fine at near and OK at distance).
Myopic anisometropic.
What is being described?
OD +2.00DS (blurry at distance and near)
OS +1.00DS (clear at distance and near).
Hyperopic anisometropic.
What is being described?
OD plano -3.00 X 180 (blurry at distance and near)
OS plano -3.50 X 180 (blurry at distance and near).
Meridional.
What is being described?
OD +6.00DS (blurry at distance and near)
OS +6.50DS (blurry at distance and near).
Isoametropic.
Constant eye turn is most common cause of what?
Amblyopia.
Is it dangerous if two images are not fused and confused for the brain?
Yes. The brain will “switch off” one eye and cause strabismus.
True or False: Intermittent eye turn leads to less severe amblyopia or no amblyopia at all.
True.
True or False: All cases of reduced vision are due to amblyopia.
False. Reduced VA can be due to organic/pathological loss of vision, psychogenic or hysterical loss of vision, or recent onset pathology.
What happens when amblyopia is left untreated?
Reduced Stereopsis, occupational exclusions (ex: cannot be a pilot), reduced visual performance (ex: driving), lack of a “reserve” or “backup eye”.
Why is it important to diagnose amblyopia in children?
Amblyopia is treatable and preventable if detected early.
What are 4 tests used in diagnosing amblyopia?
VA, plus lens test, cover test, and stereopsis.
What some treatments of amblyopia?
Remove the amblyopic factor by removing congenital cataract, repair ptosis, correct the refractive error, correct the eye turn.
What is the most common way of treating amblyopia?
Patch the good eye to encourage use of the amblyopic eye.
Optical correction for an amblyopic patient will improve VA in about what percentage of patients?
25%.
True or False: Not all children treated before the age of 5 will recover some vision.
False. Most will recover most of their vision.
Will children over the age of 10 improve by a significant amount if amblyopia is being treated?
Yes.
