Astigmatism and Presbyopia Flashcards

1
Q

When parallel rays of light enter the eye with accommodation relaxed and do not come to a single point focus on or near the retina.

A

Astigmatism

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2
Q

When the cornea has unequal curvature on the anterior surface

A

Corneal astigmatism

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3
Q

When the crystaline lens has unequal curvature on the surface or in its layers

A

Lenticular astigmatism

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4
Q

Sum of corneal astigmatism and residual astigmatism

A

Total astigmatism

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5
Q

Constitutes majority of astigmatism

A

Corneal astigmatism

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6
Q

Two principal meridians are perpendicular to each other

A

Regular astigmatism

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7
Q

Type of astigmatism in which in minus cylinder axis is found around horizontal meridian

A

With-the-rule astigmatism

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8
Q

Type of astigmatism in which in plus cylinder axis is found around horizontal meridian

A

Against-the-rule astigmatism

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9
Q

The sum of two axes of the two eyes equals approximately 180°

A

Symmetrical astigmatism

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10
Q

Infants are born with what type of astigmatism?

A

Against-the-rule astigmatism

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11
Q

The first accurate description of astigmatism was credited to?

A

Thomas Young

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12
Q

What charts are used for astigmatism?

A

Clock dials and fan dials

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13
Q

A type of symmetric astigmatism in which both eyes have with-the-rule astigmatism

A

Homologous astigmatism

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14
Q

With accommodation relaxed, both principal meridians focus in front of the retina

A

Compound myopic astigmatism

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15
Q

With accommodatoon relaxed, one meridian tends to focus behind the retina, while the other focuses in front of fhe retina

A

Mixed astigmatism

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16
Q

It is the loss of accommodation inside the eye

A

Presbyopia

17
Q

Optometric management for presbyopia

A

Reading glasses, multifocal lenses containing near add, bifocal, trifocal, and progressive add lenses

18
Q

A theory that states that presbyopia is caused by the biomechanical changes in the lens capsule and lens

A

HHG Theory

19
Q

A theory that states that presbyopia is caused by the weakening of the ciliary muscles

A

DDF Theory

20
Q

Causes of sclerosis

A

Nutritional changes, UV rays, infrared radiation

21
Q

A type of presbyopia which is known as the earliest stage; borderline, beginning, early, or pre-presbyopia

A

Incipient presbyopia

22
Q

A result of the continuous gradual decline in accommodation; a condition in which virtually no accommodation ability remains

A

Absolute presbyopia

23
Q

A condition which can still be overcome by a hard or forced ciliary effort

A

Facultative presbyopia

24
Q

Adult patients eventually report visual difficulties when faced with gradually declining accommodatjve amplitude and near task demands

A

Functional presbyopia

25
Q

A condition in which near vision difficulties result from an apparent decrease in the VA in dim light

A

Nocturnal presbyopia

26
Q

TRUE or FALSE: Signs of presbyopia include vertical wrinkles on the forehead

A

TRUE

27
Q

It is the maximum increase in optical power that an eye can achieve in adjusting its focus from as far as possible to the nearest possible

A

Amplitude of accommodation

28
Q

A small scale Snellen’s chart

A

Near chart VA

29
Q

Plus lenses are what type of lenses?

A

Convex lenses

30
Q

The DDNN rule is used for?

A

Monovision