Astigmatism and Presbyopia Flashcards
a type of astigmatism wherein the crystalline lens has an unequal curvature on the surface or in its layers
Lenticular Astigmatism
a classification of presbyopia wherein it is the earliest stage at which symptoms or clinical findings document the near vision effects of the condition
Incipient Presbyopia
also known as “short arm syndrome”
Presbyopia
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
Amplitude of Accommodation
a type of astigmatism wherein the two principal meridians are NOT perpendicular to each other
Irregular Astigmatism
a theory where it states that presbyopia is due to the sclerosis of lens
H-H-G Theory or Helmholtz-Hess-Gullstrand Theory
what does DDNN mean?
Dominant Distance Non-Dominant Near
a classification of presbyopia wherein the accommodative ability becomes insufficient for the patient’s usual near vision tasks at an earlier age than expected
Pre-mature Presbyopia
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
Astigmatism
Total Astigmatism = _______ + ________
Corneal + Residual
TRUE or FALSE.
Asian infants tend to be WTR Astigmatism.
True
TRUE or FALSE.
Hyperopes, even if corrected, usually exhibit refractive difficulty first.
True
TRUE or FALSE.
Teenage children demonstrate a shift towards ATR astigmatism
False.
They shift towards WTR astigmatism.
is when one of the principal meridians is focused behind the retina and the other is focused on the retina (with accommodation relaxed)
Simple Hyperopic Astigmatism
is when both principal meridians are focused in front of the retina (with accommodation relaxed)
Compound Myopic Astigmatism
it is the most common type of astigmatism based on the orientation of meridians
With-The-Rule (WTR) Astigmatism
a type of astigmatism wherein the cornea has unequal curvature on the anterior surface
Corneal Astigmatism
What are the 3 types of regular astigmatism?
With-The-Rule, Against-The-Rule, and Oblique Astigmatism
a theory that states that as the person ages, the reduced amplitude is due to progressive weakening of the ciliary muscle itself
D-D-F or Donder’s-Duane-Fincham Theory
a classification of presbyopia wherein there is an increase in pupil size and a decrease in depth of field
Nocturnal Presbyopia
is where the sum of the two axes of the two eyes equals to approximately 180
Symmetrical Astigmatism
is where the sum of the two axes of the two eyes does not equal to 180
Asymmetrical Astigmatism
TRUE or FALSE.
As a result of the continuous gradual decline in accommodation, functional presbyopia progress to facultative presbyopia.
False.
Functional presbyopia progresses to absolute presbyopia.
he was the first one to produce a distance test charts for astigmatism
John Green
he was credited as the first one who has an accurate description of astigmatism
Thomas Young
it is a small scale Snellen’s chart
Near chart VA
an instrument used to measure the curvature of the cornea
Keratometer
to what degree does oblique (OBL) astigmatism in minus cylinder form fall?
31-59 and 121-149 degrees
the inability of the human eye to focus on objects up close that results with aging
Presbyopia
is the most reliable source of information for cylindrical power and axis
Retinoscopy
