PRISMS: SUM HORIZONTAL-VERTICAL AND OBLIQUE, PRISMATIC EFFECT OF SPHERO-CYLINDRICAL DECENTRATION

SUM OF 2 PRISMS

(HORIZONTAL-VERTICAL BASES)

PURPOSE

Given 2 prisms with the bases oriented in the horizontal meridian (internal or external base) or vertical (upper or lower base), the value and orientation of the prism resulting from its coupling (sum) is calculated.

DATA

Enter the power and orientation of each prism, in one or both eyes.

Press calculate.

OUTCOME

The prism resulting from the sum (power and orientation). You can also observe the quadrant in which the result is found.

You also get the resulting prism if you put it only in the right eye, only in the left eye, or evenly distributed between both eyes.

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SUM OF 2 PRISMS

(OBLIQUE PRISMS)

PURPOSE

Given 2 prisms with OBLIQUE bases, the value and orientation of the prism resulting from its coupling (sum) is calculated.

DATA

Enter the power and orientation of each prism.

Press calculate.

OUTCOME

The prism resulting from the sum (power and orientation). You can also observe the quadrant in which the result is found.

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PRISMATIC EFFECT OF SPHERO-CYLINDRICAL DECENTRATION

PURPOSE

Calculate the necessary offset of a sphero-cylindrical crystal to achieve a desired prismatic effect.

DATA

The eye.

The power of the crystal in sphero-cylindrical notation.

The desired prismatic effect (power and orientation).

OUTCOME

The necessary offset in the vertical and horizontal plane.

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BIBLIOGRAPHY

1. Optical Prisms, Clinical Applications, Susan A. Cotter, Mosby, 1996