To analyze the accuracy in IOL power calculation when SRK/T and Haigis formulas are applied prior to cataract surgery in eyes with and without pseudoexfoliation (PEX) syndrome. To observe whether effective lens position (ELP) could be influenced by PEX and therefore be the source of bigger postoperative refractive surprise.

The IOL power calculation was performed with Lensstar  LS900 optical biometer prior to cataract surgery of 46 eyes of 46 patients in Clinic for eye diseases, University clinical centre of Serbia during December 2022. In 10 eyes of 10 patients PEX syndrome was noticed. Patients were examined one day after, a week after and a month after the surgery in the same clinic.

IOL power calculation was performed using two formulas SRT/T and Haigis, and surgeons involved in study decided on the power of IOL with the lowest presumed refractive error, preferably small myopia. A week and a month after the surgery refractive error (RE) was measured and its spherical equivalent (SE) compared with preoperatively presumed refractive error (PE) according to both formulas.  Data was analyzed using SPSS (SPSS for Windows, release 26.0, SPSS, Chicago, IL).

Difference between SE of RE 7 days after surgery on eyes without PEX and PE according to SRK/T formula was -0,29±0,61, and +0,18±0,64 according to Haigis formula. The difference between the two was statistically significant (p<0,001). A month after surgery difference was significantly smaller for Haigis (p<0,001 ). In eyes with PEX difference between SE and PE according to SRK/T formula 7 days after surgery was -0,44±0,55, and +0,02±0,50 according to Haigis witch was significant , as well as after a month (p<0,001). PEX in eyes did't influence the precision in calculation with SRK/T and Haigis when compared to eyes without PEX on 7 day after surgery, but a month later difference was statistically significant with SRK/T (p<0.05)

In our study Haigis formula was more precise in IOL power calculation in eyes with and without PEX syndrome. SRK/T formula slightly less precise, was in favor of myopia. Further analysis of outcome of IOL calculation in eyes with PEX will provide more precise input on its effect on ELP.