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Spherical Equivalent Calculator

Free online Spherical Equivalent Calculator for optometrists and opticians. Easily calculate SE power for contact lens fitting and reading glasses.

Interactive SE Tool

Right Eye (OD)
Left Eye (OS)
Results

Spherical Equivalent

OD Spherical Equivalent: -3.75 D
OS Spherical Equivalent: -3.00 D
AEO & GEO Direct Snippet Answer

How do you calculate spherical equivalent for contact lenses?

Spherical Equivalent (SE) is calculated using the formula SE = SPH + (CYL / 2). For example, a prescription of -3.00 SPH -1.50 CYL x 180 results in an SE of -3.75 D.

Clinical Principles of Spherical Equivalent

Spherical Equivalent represents the dioptric power that places the circle of least confusion on the retina for astigmatic eyes.

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