“Measure twice, cut once” applies powerfully to cataract surgery. Relying on a single biometry device increases the chance of rare outliers that result in residual prescription and the need for enhancement procedures. By using two independent technologies — for example, two swept‑source optical coherence tomography biometers or optical biometry plus swept‑source OCT — surgeons can verify measurements and resolve discrepancies before surgery. This improves refractive accuracy and reduces the proportion of eyes falling outside the desired target.
Large studies show that even small measurement differences in axial length or corneal curvature can translate into meaningful refractive error. Double‑checking biometry is therefore a practical way to tighten results, especially in eyes with unusual anatomy.
What this means for you
- Double biometry is about preventing surprises, not adding complexity.
- Better verification reduces the likelihood of needing further corrective procedures.
Questions to ask
- “Do you routinely verify my lens power using more than one biometry method?”
- “How do you handle discrepancies between different measurements?”
References
- Omoto MK, Torii H, Masui S, et al. Ocular biometry and refractive outcomes using two swept‑source optical coherence tomography biometers. Scientific Reports. 2019;9(1):6557.
- Arens S, Hager A, Ohlendorf A, et al. Comparative analysis of refractive outcomes following cataract surgery with two optical biometry devices. American Journal of Ophthalmology. 2024;258:120–128.
