Astigmatism

An irregularly shaped cornea or lens that prevents light from focusing properly on the retina, the light-sensitive surface at the back of the eye

Astigmatism

What focal line image does power in the horizontal plane projects ?

Vertical

What focal line image does power in the vertical plane projects ?

Horizontal

Clinical classification of Astigmatism where the cornea has unequal curvature on the anterior surface

Corneal Astigmatism

Clinical classification of Astigmatism when the crystalline lens has an unequal curvature or its layer

Lenticular Astigmatism

Clinical classification of Astigmatism where it is the sum of corneal and lenticular astigmatism

Total Astigmatism

Clinical classification of Astigmatism based on principal meridians when the two principal meridians are perpendicular to each other

Regular Astigmatism

Clinical classification of Astigmatism based on principal meridians when the two principal meridian are not perpendicular to each other

Irregular Astigmatism

In regular astigmatism, where the greatest refractive power is within the vertical meridian. . Their axis is 0-30 and 150-180

With the rule

In regular astigmatism, where the greatest refractive power is within the horizontal meridian. Their axis is 60-120

Against the rule

In regular astigmatism, where the greatest refractive power is within 030 of the oblique meridians. Their axis is 31-59 and 121-149

Oblique

Clinical Classification of Astigmatism based on focal points

Compound Myopic

Clinical Classification of Astigmatism based on focal points

Simple Myopic

Clinical Classification of Astigmatism based on focal points

Mixed

Clinical Classification of Astigmatism based on focal points

Simple Hyperopic

Clinical Classification of Astigmatism based on focal points

Compound Hyperopic

Clinical Classification of Astigmatism based on focal points relative location where the principal meridians or axes of the two eyes are symmetrical and the sum of the two axes of the two eyes equals approximately 180

Symmetrical Astigmatism

Clinical Classification of Astigmatism based on focal points relative location where the principal meridians or axes of the two eyes are not symmetrical and the sum of the two axes of the two eyes does not equal approximately 180

Asymmetrical Astigmatism

The infants already have against the rule astigmatism

True

The preschool children with little to no astigmatism

True

As the kid grow older, they will have the with the rule astigmatism

True

Adults will have against the rule astigmatism

True