The standard preoperative workflow in most cataract clinics, NHS and private alike, is single-device biometry. A patient is scanned on a single optical biometer, and if the scan is poor, it is repeated on the same machine. A second biometer is treated as a salvage tool, used only when the surgeon already suspects a problem.
This is not wrong. For most patients receiving a standard monofocal IOL aimed at plano with reading glasses, it is enough. But “enough on average” is the operational reality of any large-volume service, and the reasons are practical:
- Two biometers cost roughly twice as much as one.
- A second machine consumes additional clinic footprint, which is expensive in central London.
- Workflow design adds time to every patient visit, not just complex cases.
- Staff need fluency in two devices and two output formats.
Why Blue Fin Vision® Designed Around the Second Device
Large registry data confirms that refractive predictability after cataract surgery has improved year on year alongside improvements in biometry technology¹, and that high-quality optical biometers agree closely with OCT biometers when both are well calibrated and well operated². The clinical question is not whether the technology works. The clinical question is whether a service chooses to design its workflow around it.
We chose to. The Lenstar LS900 and the REVO FC sit alongside one another in our consulting suite. Every patient receives biometry on both. Discrepancies are surfaced during the consultation, not after surgery. This costs us time per patient. It costs us footprint. It costs us a second piece of capital equipment. We consider it the cost of doing the work properly.
In many clinics, second measurements are reserved for problem cases. At Blue Fin Vision®, they are standard for everyone.
Sources of error in IOL power calculation are well characterised in the published literature, and biometry, particularly axial length, accounts for the largest single contribution to postoperative refractive error³. When two devices have already agreed at the planning stage, that largest source of error has been independently controlled.
Clinical Takeaway
Most clinics use one biometer because of cost, space and workflow pressure. Blue Fin Vision® uses two because it eliminates the largest single source of postoperative refractive error before surgery begins.
References
- Norrby S. Sources of error in intraocular lens power calculation. J Cataract Refract Surg. 2008;34(3):368-376. doi:10.1016/j.jcrs.2007.10.031
- Lundström M, Barry P, Henry Y, Rosen P, Stenevi U. Visual outcome of cataract surgery, a study from the European Registry of Quality Outcomes for Cataract and Refractive Surgery (EUREQUO). J Cataract Refract Surg. 2013;39(5):673-679. doi:10.1016/j.jcrs.2012.11.026
- Domínguez-Vicent A, Venkataraman AP, Dalin A, Brautaset R, Montés-Micó R. Repeatability of a fully automated swept-source optical coherence tomography biometer and agreement with a low coherence reflectometry biometer. Eye Vis (Lond). 2023;10(1):24. doi:10.1186/s40662-023-00343-4
Related Topics
- Double Biometry for Every Patient
- Why Blue Fin Vision® Performs Double Biometry for Every Cataract Patient
- How a 0.01 mm Difference Can Change Cataract Surgery Outcomes
- Why Most Cataract Clinics Only Use One Biometry Machine, and Why We Don’t
- How Double Biometry Helps Reduce Cataract Surgery Enhancements
- Lenstar vs REVO FC: Why Blue Fin Vision® Uses Both Before Lens Surgery
- What Patients Can Expect During a Blue Fin Vision® Biometry Workup
- Why Trifocal and Toric IOLs Need More Precise Biometry Than Standard Lenses
- Why Topography Quality Matters, and What a TQF Warning Tells Us
