No report generated yet.
A correction ratio below 1.0 indicates undercorrection (the laser delivered less than intended); above 1.0 indicates overcorrection. The ratio is only shown when at least 1.0 D of correction was attempted, because small denominators are unstable.
Positive values mean the eye landed more hyperopic than intended (overcorrected myopia); negative values mean more myopic than intended (undercorrected / regressed). Absolute error is its magnitude and drives the ±0.25/±0.50/±1.00 D predictability percentages.
Because achieved correction tracks the programmed treatment, the average prediction error is the shortfall or excess to compensate. If a subgroup is on average undercorrected, the suggestion is to increase the programmed correction by the rounded mean error (0.25 D steps); if overcorrected, to reduce it. These are candidate directions to validate, not values to apply directly.
Lines of CDVA change use logMAR = −log₁₀(decimal VA). Losing ≥2 lines is a safety concern. Indices are only shown when the relevant visual acuities are entered as decimals.
Refractive results stabilise at different rates. LASIK and CLEAR are usually stable by ~1 month; PRK typically requires ~3 months because of epithelial remodelling and potential regression. The Data Quality tab flags refractions taken before these windows so that early, unstable results do not bias the nomogram.
Two surgeons on the same platform can achieve different outcomes because of differences in laser calibration and environment (humidity, temperature), flap or cap creation, epithelial handling, hydration, ablation profile, optical zone, and patient population. A nomogram optimised elsewhere does not necessarily transfer.
Small samples create false signals; validate prospectively before implementing a subgroup correction. Corrections should never be applied on the basis of ethnicity alone. Instead this tool analyses measurable variables — attempted correction magnitude, keratometry, corneal thickness, optical zone, age and procedure — so that any real population difference becomes visible through physiology rather than assumption.
This version reports refractive-astigmatism outcomes (residual cylinder magnitude and predictability). Full Alpins vector analysis (correction index, angle of error, index of success) is not yet included and would be a sensible next step for a dedicated toric/astigmatic nomogram.