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WorksheetsACOD WS1 Astigmatic
Total questions: 10
Worksheet time: 5mins
According to toric expression, the number on the bottom left side of the expression represents
The cross curve on the back surface
The base curve on the back surface
The sphere curve on the front surface
The base curve on the front surface
A prescription reads -2.50 / -1.75 x 60. The type of astigmatism corrected by this prescription is
Mixed astigmatism
Simple myopic astigmatism
Compound myopic astigmatism
Compound hyperopic astigmatism
A lens prescription reads -3.00 / -1.75 x 45. The 45 represents:
The sphere power of the prescription
The axis of the prescription
The cylinder power of the prescription
The prism power of the prescription
A lens prescription reads -3.00 / -1.50 x 180. The principal powers are
-3.00 and -4.50
-1.50 and -4.50
-3.00 and 180
-3.00 and -1.50
Standard Axis Notation operates from 0º to 180º and involves
Right to left movement
Clockwise rotation
Left to right movement
Anti-clockwise rotation
The lens type needed to correct an astigmatism is
Plano-cylindrical or sphero-cylindrical
Aspheric
Double Aspheric
Double Spherical
An optical cross represents
The two principal meridians of an astigmatic lens
One principal meridian of an astigmatic lens
Two focal points of a astigmatic lens
The two principal meridians of a spherical lens
In the Thin Lens Formula, the Symbol F1 stands for
Total lens power
Front surface power
Formula One
Focal Point
Changing the written expression of a prescription from plus cylinder form to minus cylinder form is known as
Simple transposition
Prentice’s Rule
Snell’s Law
Toric transposition
A sphero-cylindrical lens can correct
Compound myopic astigmatism
Compound hyperopic astigmatism
Mixed astigmatism
All of the above
