Astigmatism and Presbyopia Flashcards
When one of the principal meridian is focused on the retina and behind the retina
Simple Myopic Astigmatism
Two meridians are not perpendicular to each other
Irregular Astigmatism
Both principal meridians are focused behind the retina
Compound Hyperopic Astigmatism
The first one to produce distance test charts for astigmatism
John Green
Refractive condition in which a variation of power exists in different meridians
Astigmatism
Common form of astigmatism that causes the cornea to be oblong shaped with high refractive power in the vertical meridian
With-the-Rule Astigmatism
Unequal curvature of the cornea
Corneal Astigmatism
What does D-D-F stands for?
Donder’s-Duane-Fincham Theory
Astigmatism that came from lens?
Lenticular Astigmatism
The earliest stage of presbyopia and performs well in vision testing
Incipient Presbyopia
Condition in which virtually no accommodative ability remains
Absolute Presbyopia
Can stil be overcome by a hard or forced ciliary effort
Faculative Presbyopia
Sum of the corneal astigmatism and residual astigmatism
Total Astigmatism
One of the principal meridian is focused on the retina and the other is not focused on the retina
Simple Astigmatism
Accommodation is paralyzed, one meridian tends to focus is behind the retina and in front of the retina
Mixed Astigmatism
Loss of accommodation inside the eye
Presbyopia
Loss of “auto-focus”
Presbyopia
Improves near vision in emmetropic presbyopes
Corneal Inlays
H-H-G Theory stands for?
Helmholtz-Hess-Gullstrand Theory
Accommodative ability becomes insufficient for patient’s usual near vision tasks at an earlier age than expected.
Pre-mature Presbyopia
Touches the cornea with High Radiofrequency and by collagen shrinkage reshapes the cornea
Conductive Keratoplasty
Distant vision remains unchanged
Presbyopia
When the two principal meridians are perpendicular to each other
Regular Astigmatism
Principal meridians is focused behind the retina and the other is focused on the retina
Simple Hyperopic Astigmatism
Both principal meridian infront of the retina
Compound Myopic Astigmatism
Axes of the two eyes are not symmetrical
Asymmetrical Astigmatism
Axes of the two eyes are symmetrical
Symmetrical Astigmatism
Parallel rays of light enter the eye and do not come to a single point focus on or near the retina
Astigmatism
The medical science of symptoms.
Symptomatology
Small scale snellen’s chart
Near Chart VA
