IOL Power Calculator — SRK-T Formula

Calculates intraocular lens (IOL) power for cataract surgery using the SRK-T formula: P = A − 0.9K − 2.5L, where A is the lens constant, K is average keratometry (diopters), and L is axial length (mm). The SRK-T formula is preferred for eyes with axial length >24.5 mm.

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Clinical Guidance

BMI is a screening measure of body size, not a direct measure of body fat. The standard WHO categories are underweight (<18.5), normal (18.5–24.9), overweight (25–29.9), and obese (≥30).

BMI can overestimate body fat in athletes with high muscle mass and underestimate it in older adults with low muscle mass. Interpret it alongside waist circumference and clinical context rather than as a standalone diagnosis.

⚕ Clinical Disclaimer: These calculators are for educational and reference purposes only. Always verify results with qualified clinical judgment and current clinical guidelines. Do not use as a sole basis for medical decisions.
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How It Works

Calculates intraocular lens (IOL) power for cataract surgery using the SRK-T formula: P = A − 0.9K − 2.5L, where A is the lens constant, K is average keratometry (diopters), and L is axial length (mm). The SRK-T formula is preferred for eyes with axial length >24.5 mm

Each component has a specific meaning:

  • SRK-T formula: P = A − 0 — The srk-t formula: p = a − 0 recorded for the scenario being assessed.

Note: Interpret the iol srk-t formula result against the thresholds and context described above.

How to Use

Enter the SRK-T formula: P = A − 0 for the scenario you are assessing. Calculates intraocular lens (IOL) power for cataract surgery using the SRK-T formula: P = A − 0.9K − 2.5L, where A is the lens constant, K is average keratometry (diopters), and L is axial length (mm). The SRK-T formula is preferred for eyes with axial length >24.5 mm. Use the iol srk-t formula result to inform your calculation.

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