If you want to use Haigis L formula for post lasik patients, then you must convert your K reading (in mm) to a corrected radius of curvature for such patients. Once corrected you can input this to Haigis formula available in your biometry machine. You can also use the Haigis formula available online by simply clicking on the link. There you have to input the corresponding corrected K values displayed against R.I or n as 1.3315.
If the below does not work for you, then you can directly click on the link here to access the tool: https://sheet.zohopublic.com/sheet/published/9grr82464889571924e28bfbd48ba62094a3c