About the T2 Formula

The SRK/T formula, widely used by surgeons to predict which power of lens implant to insert during cataract surgery, contains a systematic error which leads to non-physiological behaviour and which contributes to inaccurate IOL power prediction.

The T2 Formula was developed by Guy Smith, Dave Cooke and Richard Sheard to correct the problems of the SRK/T. The T2 Formula may be directly substituted for the SRK/T formula, including using the same A constant for the IOL.

In comparison to SRK/T the T2 Formula results in a 10% improvement in prediction accuracy for refractive outcomes and a significant improvement in the proportion of patients achieving within ±0.5 dioptres of target refraction.

Full details of the T2 Formula were published in the November 2010 issue of the Journal of Cataract & Refractive Surgery. Click here to view the article abstract.

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