Abstract
Purpose: :
To evaluate the accuracy of intraocular lens (IOL) power calculation formulae ( Holladay II, Holladay I, Hoffer-Q, and SRK-T) in two modern multifocal IOLs (Tecnis Multifocal ZMB00 and Alcon ReSTOR +3 SN6AD1).
Methods: :
42 patients had the SN6AD1 implanted while 20 patients had the ZMB00 lens implanted. All lenses were implanted by a single surgeon. Preoperative axial lengths were measured with partial coherence interferometry (IOLMaster.) Keratometry values were based on IOLMaster K values. All patients had refractions measured at least one week postoperatively. Holladay IOL Consultant software was utilized for IOL selection and postoperative data calculations. Lenses implanted were routinely selected based on the Holladay II formula.
Results: :
Mean refractive error for the Alcon SN6AD1 was 0.006, -0.001, -0.003 and 0.001 for the Holladay II, Holladay I, Hoffer-Q, and SRK-T respectively while the mean absolute refractive error was 0.336, 0.370, 0.411, and 0.368 respectively. Mean refractive error for the Tecnis ZMB00 was -0.013, -0.048, -0.007, and -0.104 for the Holladay II, Holladay I, Hoffer-Q, and SRK-T respectively while the mean absolute refractive error was 0.255, 0.242, 0.260, and 0.266 respectively. Using the Holladay II formula 94% of eyes receiving the SN6AD1 were within +/- 0.5D spherical equivalent refractive error while 95% of eyes receiving the Tecnis ZMB00 were within +/-0.5D spherical equivalent refractive error. 55/62 (89%) of eyes in this study had axial lengths between 22 and 26mm.
Conclusions: :
All 4 modern theoretical IOL calculation formulae performed similarly in IOL power calculation for the Restor and Tecnis Multifocal IOLs in this study population of eyes with axial lengths between 22 and 26mm.
Keywords: treatment outcomes of cataract surgery • anterior segment • intraocular lens