Updated: Apr 14
While using a two variable formula like SRK T and Holladay I in very high axial length patients, unexpected hyperopic surprise has often been observed. To reduce such errors, the Wang & Koch nomogram ( see 'Biometry' quick guide section for Wang & Koch nomogram), is recommended to be used. However such nomograms are left to calculations in a busy practice. A Table with high axial length (starting 25.20 mm) with corresponding Wang & Koch adjusted AL has been computed for easy reference. All you need to do is to refer the adjusted axial length against the measured axial length with your preferred optical biometry machine ( IOL Master ).
Best to apply :
A regression analysis of high axial length patients with your preferred SRK T or Holladay I formula can give you an idea if W&K nomogram will be useful to follow in future. All the best !!
The Wang-Koch adjustment should only be applied in eyes with ALs longer than 27.0 mm that have IOL power calculation with the Holladay 1 formula ( J Cataract Refract Sur 2018 Jan;44(1):17-22 )
Table chart conversion of Wang & Koch Nomogram for Holladay I and SRK T formula.