Ophthalmic Spherical equivalent Calculator Online
Ophthalmic Calculators
What is spherical equivalent ?
A Spherical Equivalent is an estimate of your eyes’ refractive error, calculated independently for each eye. It is calculated by merging the spherical (nearsightedness or farsightedness) and cylindrical (astigmatism) components of your refractive error but is usually not accurate enough for ordering glasses that would provide the sharpest vision. An analogy would be converting a football-shaped surface where half of the surface is steeper than the rest into a completely spherical surface like a basketball. It is not an exact fit, but the idea is to get as close as possible.
Spherical equivalents are often used by eye doctors to prescribe contact lenses for patients with low astigmatism or patients who want colored contact lenses (very few colored contact lens brands are able to correct astigmatism), to reduce the astigmatism in an eyeglass prescription for patients who have trouble adapting, or to compare overall changes in prescriptions.
