Calculation of eye length

Eye length is calculated using a model with corneal values and refraction and is a guide value. This guideline value should not be used for diagnosis, but it can be used as an evaluation aid if a biometer is not available

Guide values are calculated for children aged 8 to 12 years. These values may deviate by ±0.73 mm or ±3.0 % of the true measured axial length measurement. Ninety-five percent of the values derived from the formula fall within about three-quarters of a millimeter of the "true" axial length (measured with an interferometric biometer).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.

Adapted from:

AMA	Tideman JWL, Polling JR, Vingerling JR, et al. Axial length growth and the risk of developing myopia in European children. Acta Ophthalmol. 2018;96(3):301–309. doi:10.1111/aos.13603
MLA	Tideman, Jan Willem Lodewijk et al. “Axial length growth and the risk of developing myopia in European children.” Acta ophthalmologica vol. 96,3 (2018): 301-309. doi:10.1111/aos.13603
APA	Tideman, J., Polling, J. R., Vingerling, J. R., Jaddoe, V., Williams, C., Guggenheim, J. A., & Klaver, C. (2018). Axial length growth and the risk of developing myopia in European children. Acta ophthalmologica, 96(3), 301–309. doi:10.1111/aos.13603
NLM	Tideman JWL, Polling JR, Vingerling JR, Jaddoe VWV, Williams C, Guggenheim JA, Klaver CCW. Axial length growth and the risk of developing myopia in European children. Acta Ophthalmol. 2018 May;96(3):301-309. doi: 10.1111/aos.13603. Epub 2017 Dec 19. PMID: 29265742; PMCID: PMC6002955.