Abstract
Purpose: :
To reconstruct wavefront aberrations of pseudophakic eyes with known IOL geometry using an individualized eye model.
Methods: :
Ocular components and optics of seven patients (twelve pseudophakic eyes) with known aspherical IOL designs (Acri.Tec A-Design and LC-Design) were measured including corneal topography (Atlas® 9000), anterior chamber depth (VisanteTM OCT), axial length (IOLMaster®), IOL decentration and tilt (Purkinjemeter) as well as ocular wavefront aberrations using a Shack-Hartmann wavefront sensor (i.Profiler®). The data then was converted to create personalized eye models using the optics design program ZEMAX®. Ray tracing was performed to reconstruct the ocular wavefront with the model and compared to the actual measured wavefronts of the Shack-Hartmann sensor for a 5 mm pupil size. Hotelling T2 test and T-test were performed to compare the measured and reconstructed wavefront aberrations.
Results: :
Mean sphere, cylinder and axis of the measured and reconstructed wavefronts were sph -0,84 D cyl -0,35 D axis 79° and sph -0,96 D cyl -0,08 D axis 20° respectively (Hotelling T2 p = 0.65). Mean HO-RMS of the measured wavefronts was 0,33 µm versus 0,38 µm for the reconstructed wavefronts (T-test p = 0.19). In general the results were in good agreement with previous studies. Controlled modification of the personalized eye models, e.g. shorten/elongate eye-length/ACD or decentered/tilted IOL, showed various asymmetric effects. IOL tilt showed larger effects on optical changes than IOL decentration.
Conclusions: :
Provided accurate prediction of the anatomic IOL position post-operatively is possible, raytracing, based on true biometric parameters including corneal shape as well as IOL design parameters, could offer an IOL calculation method which does not have to rely on statistical optimization methods.
Keywords: cataract • aberrations • intraocular lens