Wang-Koch Adjustment (Axial Length)
Optimizes axial length for eyes > 25.0mm to avoid hyperopic shifts.
This calculator is a support tool intended exclusively for health professionals. It does not replace clinical judgment. The final decision regarding diagnosis and treatment is the sole responsibility of the professional.
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About this Calculator đŸ’¡
The Wang-Koch Adjustment is an advanced mathematical method used in surgical ophthalmology to optimize intraocular lens (IOL) power calculations for patients with high myopia, specifically those with a long axial length (typically greater than 25.0 mm). In traditional third-generation biometry formulas, such as Holladay 1, measuring a very long eye can lead to prediction errors, often resulting in a postoperative 'hyperopic surprise'—meaning the patient ends up with unexpected farsightedness after cataract surgery. To correct this systematic bias, Drs. Wang and Koch developed regression equations that adjust the measured axial length to an 'optimized axial length.' This adjusted value is what should be entered into calculation formulas to select the correct IOL. It is crucial to note that this is not a disease diagnostic tool, but rather a surgical planning resource for cataract surgeons, aimed at improving refractive precision and visual satisfaction for high myope patients.
Reference Values
- • Optimized AL. Use this value in IOL formulas (e.g., Holladay 1).
- • Attention: This adjustment is intended for eyes with AL > 25.0 mm.
Formula
AL_opt = 0.8285 Ă— AL_measured + 4.2636
Reference
Wang L, et al. Optimizing intraocular lens power calculations in eyes with axial lengths above 25.0 mm. J Cataract Refract Surg. 2011.