What vault is
Vault is the gap between the back surface of the ICL and the front surface of your natural crystalline lens. It is measured in microns on anterior-segment OCT. The lens is designed to float in the posterior chamber, held by four footplates resting in the ciliary sulcus, and the vault tells the surgeon whether the chosen size fits your eye.
- Ideal vault: roughly 250 to 750 microns (about the thickness of one to one and a half corneas)
- Low vault (under about 150 microns): the ICL can touch the natural lens, raising cataract risk
- High vault (over about 1,000 microns): the lens pushes the iris forward, narrowing the drainage angle and raising pressure; the endothelium is closer to the implant
Vault also changes with pupil size and decreases slightly over years as the natural lens thickens with age, which is why annual checks matter.
How the lens is sized
The EVO ICL comes in four lengths (12.1, 12.6, 13.2 and 13.7 mm). The surgeon has to predict which length will produce a good vault in your particular eye. Methods, from simplest to most precise:
| Method | What it measures | Notes |
|---|---|---|
| White-to-white (WTW) + anterior chamber depth | Horizontal corneal diameter and chamber depth | Manufacturer nomogram; adequate for most eyes but a proxy for the real sulcus |
| Anterior-segment OCT formulas | Angle-to-angle, crystalline lens rise, chamber geometry | Newer formulas (e.g., KS, NK) improve prediction |
| Ultrasound biomicroscopy (UBM) | Direct sulcus-to-sulcus measurement | Most direct; operator-dependent; not available in every clinic |
Many high-volume surgeons use two methods and cross-check. Ask which is used at your clinic. A clinic that sizes only from WTW is following the standard, not cutting corners, but a clinic that adds OCT or UBM is reducing your exchange risk.
How often sizing is wrong
Published exchange rates for vault outside range sit in the low single-digit percentages, higher in eyes with unusual anatomy (very large or small corneas, flat or steep chambers). A first-eye vault that comes out unexpectedly high or low is sometimes used to adjust the second eye's size, which is one argument for a short gap between eyes; see one eye at a time or both.
What a good clinic does when vault is off
- Measures vault by OCT at day one and week one, in the record, in microns
- Waits for the eye to settle unless vault is dangerously high or low
- Exchanges the lens for the adjacent size, with the exchange included in the package
- Rotates a toric lens by 90 degrees when the alternative size is not available, in select cases
Questions that expose a weak ICL practice
- "What vault did you get on your last ten patients?" A surgeon who tracks outcomes will answer with numbers.
- "Is a lens exchange included if vault is out of range?" It should be.
- "Which size did you choose for me and why?" You should get a specific answer referencing your measurements.
Why this matters for medical travellers
An exchange, if needed, is usually done within the first month. If you have gone home, that means a second trip or a local surgeon willing to exchange a lens they did not implant. Both are workable but neither is free. The best protection is a clinic that sizes carefully and documents vault before you fly. Ask for the lens size, power, serial number and day-one vault in your operative report.
Frequently asked questions
What is a normal ICL vault?
Roughly 250 to 750 microns, though slightly outside that range is often acceptable and monitored rather than exchanged.
Can vault change over time?
Yes. It typically decreases slowly over years as the natural lens thickens, and it changes with pupil dilation and light conditions.
Is UBM necessary for ICL sizing?
Not required, and many excellent results come from OCT or WTW-based sizing. UBM or OCT formulas reduce, but do not eliminate, exchange risk.
Want a surgeon who sizes with OCT or UBM?
We can tell you which Colombian ICL surgeons cross-check sizing and include exchanges in their package.
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