Spherical · Optics

Where does the eye focus light?

The spherical (SPH) value describes where the eye focuses light. Minus values indicate myopia, plus values hyperopia.

Myopia Minus (−) sphere
Hyperopia Plus (+) sphere
Incoming distant light → Blurred
SPH −2.00 D

Myopia — Distance Blur

Light ray Sharp focus (retina) Blurred focus Corrective lens
Myopia · Vision

What Does a Myopic Eye See Far Away?

In myopia, incoming distant light focuses in front of the retina; as the number (SPH) grows, distance vision blurs. Change the number and watch how the smallest readable line on the Snellen chart shifts.

SPH −2.00 D

Distance ≈ 20/70 vision