Estimation of Axial Length

The estimated axial length is calculated based on a model using corneal values and refraction and serves as a guideline. This estimate value should not be used for diagnostic purposes but can provide supportive assessment if a biometer is unavailable.

The estimate values are calculated for children aged 8 to 12. These values may deviate by ±0.73 mm or ±3.0% from the real axial length measurement. 95% of the values derived from this formula are within approximately three-quarters of a millimeter of the "true" axial length (measured using an interferometer biometer).

Based on Morgan PB, McCullough SJ, Saunders KJ. Estimation of ocular axial length from conventional optometric measures. Cont Lens Anterior Eye. 2020 Feb;43(1):18–20.