Astigmatism and Presbyopia Flashcards
It is 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
When the crystalline lens has an unequal curvature on the surface or in its layers.
Lenticular Astigmatism
Total Astigmatism = _____ + residual
Corneal
With-the-rule astigmatism in minus lenses lies on what axis?
1-30;150-180
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
When both principal meridians are focused either in front or behind the retina (with accommodation relaxed)
Compound Astigmatism
What are the two types of Symmetric Astigmatism?
Homologous and Heterologous
Give one symptom of Astigmatism
Letter confusion
Give a clinical test used for Astigmatism.
Keratometry
The first accurate description of Astigmatism as such is credited to ________.
Thomas Young
Give two examples of Astigmatic Charts.
Clock Dial and Fan Dial
Refractive condition in which a variation of power exists in different meridians of the eye.
Astigmatism
True or False. In general, there is a significant difference between males and females when it comes to astigmatism.
False
True or False. In Symmetrical Astigmatism, the sum of two axes of the two eyes equals 180 degrees.
True
True or False. Infants are born with WTR Astigmatism
False
The inability of the human eye to focus on objects up close that results with aging.
Presbyopia
Presbyopia usually starts at what age?
40-50
Presbyopia is also called as?
Short Arm Syndrome
Presbys:____;Ops:______
old;eye
It is a theory which proposes that presbyopia is due to changes in the lens.
H-H-G Theory
It is the earliest stage of Presbyopia.
Incipient Presbyopia
Condition which can still be overcome by a hard or forced ciliary effort.
Facultative Presbyopia
It is a loss of accommodation inside the eye.
Presbyopia
DDNN stands for?
Dominant-Distance;NonDominant-Near
Presbyopia in which virtually no accommodative ability remains.
Absolute Presbyopia
A theory which proposes that Presbyopia is muscle-based.
D-D-F Theory
True or False. Weakening of the CIliary Muscles is one of the etiology of Presbyopia.
True
True or False. Presbyopia is the advancement of near point with increasing age.
False
True or False. One symptom of Presbyopia is Diplopia.
True
True or False. Presbyopia can be manages using Bifocal Lenses.
True
