IOP adjusted for central corneal thickness (Ehlers)
Approximate Goldmann IOP adjusted for central corneal thickness with the Ehlers linear correction. An approximation only.
Inputs
0 of 2mmHg
µm
When to use
- Interpreting a Goldmann applanation reading in an unusually thin or thick cornea, as a rough estimate.
Pearls and pitfalls
- Correction formulas disagree with each other and are not validated for individual patients; many glaucoma services record CCT as a risk factor instead of correcting IOP.
- Not valid after corneal refractive surgery, in corneal edema or with other tonometers.
Why use
Shows the size of the corneal-thickness effect while making clear it is an approximation.
Adjusted IOP ≈ measured IOP − (CCT − 520 µm) × 0.07 mmHg/µm (7 mmHg per 100 µm from 520 µm)