MODULE 6: DEVELOPMENT OF AMETROPIA Flashcards

1
Q

process where the refractive power of the anterior segment as well as axial length adjust to reach emmetropia

A

Emmetropization

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2
Q

Desired results of emmetropization

A

▪️ Parallel rays of light come to a point focus or near point on the retina
▪️ The refractive condition of the eye centers on a refractive range around low hyperopia to emmetropia

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3
Q

_________________ of light come to a point focus or near point on the retina

A

Parallel rays

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4
Q

The refractive condition of the eye centers on a refractive range around__________________

A

low hyperopia to emmetropia

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5
Q

Prescription given the benefit of the doubt na emmetropic

A

+0.50 to 1.00D of hyperopia with SD of +1.00D

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6
Q

Theory of emmetropization
- nature and genetics are guiding and key factor

A

Passive process

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7
Q

Theory of emmetropization
- natural growth and development of most eye are likely predictable

A

Passive process

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8
Q

Theory of emmetropization
- predictable programmed growth

A

Passive process

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9
Q

Key factors of nature in emmetropization as a passive process

A
  • growth in vitreal chamber
  • crystalline lens flattens
  • anterior chamber deepens
  • cornea flattens
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10
Q

Key factors of genetics in emmetropization as a passive process

A
  • hereditary aspect of myopia
  • likelihood of being myopic is directly correlated to number of myopic patients
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11
Q

Likelihood of being myopic if both parents are myopic

A

42%

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12
Q

Likelihood of being myopic if one parent is myopic

A

22.5%

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13
Q

Likelihood of being myopic if neither is myopic

A

8%

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14
Q

Theory of emmetropization

Major influences in active process

A

Nature and environment

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15
Q

Theory of emmetropization

Major influences in passive process

A

Nature and genetics

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16
Q

Theory of emmetropization

Visual system is able to compute the existence of a blur and then respon appropriately to compensate for it

A

Active process

17
Q

Elements of emmetropization

A

• Healthy eye
• Healthy environment
• Operational refractive range
• Intact emmetropization mechanism

18
Q

develop when there is a failure in the emmetropization process

19
Q

Ametropia results from _________ in the correlation of ocular components

20
Q

eye does not possess enough optical power for its axial length

21
Q

Most common refractive error in children (most will not need optical correction)

22
Q

Significant hyperopia is more likely to cause

23
Q

Uncorrected hyperopia can cause:

A

Blurred vision
Amblyopia
Binocular dysfunction (strabismus)
Learning problems

24
Q

eye possess too much optical power for its axial length

25
2 types of childhood myopia
Congenital myopia & developmental myopia
26
-5.00Dsph in a child 6y/o or less with history of signs associated with nearsightedness assessed by parents since early infancy
Congenital myopia
27
presents at 7-10y/o with moderate degrees of myopia
Developmental myopia
28
Acquired myopia
Developmental myopia
29
caused by an irregularity on corneal surface
Astigmatism
30
EOR differs between 2 eye, with 2D difference
Anisometropia
31
Age-related changes in astigmatism: ATR at birth
“sagging” of the cornea of the still developing globe
32
Age-related changes in astigmatism: WTR at preschool
Stiff upper tarsal plate exerting pressure on horizontal
33
Age-related changes in astigmatism: ATR middle life and beyond
upper tarsal plate looses is rigidity
34
unilateral or less often, bilateral, decrease in BCVA in an otherwise structurally normal eye
Amblyopia
35
Types of Amblyopia
Visual deprivation Strabismic amblyopia Refractive amblyopia
36
Type of amblyopia caused by complete or partial obstruction of the visual axis
Visual deprivation
37
Type of amblyopia due to constant, non-altering, or unequally alternating tropias
Strabismic amblyopia
38
Type of amblyopia due to untreated unilateral or bilateral EOR
Refractive amblyopia