Pre-operative IOL power calculation for standard cataract surgery.
Validated primarily for eyes with normal to long axial lengths (>22.0 mm).
Regression model used to predict the Effective Lens Position (ELP).
Section 2
Formula & Logic
The SRK/T Model
The SRK/T (Shearing-Retzlaff-Kraff/Theoretical) formula is a non-linear theoretical regression model. Unlike earlier linear formulas, it uses a computed corneal height based on keratometry and axial length to better estimate where the lens will sit post-operatively.
Section 3
Evidence Appraisal
Standard Reference
Development of the SRK/T differential equation-based theoretical IOL power formula.
Retzlaff JA et al. • J Cataract Refract Surg.. 1990;Large-scale validation (n=1,417) confirming its accuracy over earlier SRK models.
