Evaluation of Decentration, Tilt and Angular Orientation of Toric Intraocular Lens

Abstract

Purpose The aim of this study was to develop software for the universal objective evaluation of factors influencing intraocular correction of astigmatism, such as decentration, tilt, axial position and angular orientation the toric intraocular lens (IOL). Patients and Methods Software was developed using the MS Visual Studio environment. The analysis was presented using images of 67 eyes with an implanted IOLs of the SN6ATx model series. Decentration and angular position of the lens were obtained from images of the anterior segment of the eye, using a Visucam unit. Tilt was measured on tomographic images from OCT Avanti (in meridian of highest tilt and perpendicular meridian) and preoperative biometry parameters of eye (axial length, anterior chamber depth – ACD, ocular lens thickness – LT, limbus diameter and mean keratometry value) including postoperative anterior chamber depth (pACD) were measured using Lenstar LS900. Results Applying the software methodology to the evaluation of individual toric IOL parameters, the following results were obtained: mean decentration 0.25 ± 0.17 mm which was observed in 61.19% of eyes, mean misalignment to the planned axis equal to 3.8 ± 3.6 degrees, mean highest inclination equal to 3.7 ± 1.2 degrees and mean difference of pACD and ACD was equal to 1.46 ± 0.31 mm. There was only a weak nonsignificant correlation between preoperative ACD versus decentration and tilt of IOL or a weak significant correlation between preoperative LT and both decentration and misalignment of IOL. Conclusion The use of the presented methodology for determining the positional parameters of the toric IOL provided comparable results with the results of recent studies. Software design can be considered as a suitable alternative to previously published techniques, with the significant advantage of the possibility of using universal input images, their graphical editing and especially the possibility of comprehensive analysis of all parameters.

Comparison of toric intraocular lens tilt and decentration measurement using dynamic Purkinje-meter and anterior segment optical coherence tomography

“…Xiao et al 30 (AS OCT, corneal topographic axis) measured values of tilt 5.6° ± 1.6° and decentration 0.18 mm ± 0.12 mm similar to the values from AS OCT in our study. Other published results of IOL position (presented in the same format) are given relative to the pupillary axis or pupil center, and thus the comparison with our results is questionable: tilt 2.9° ± 0.9° and decentration 0.56 mm ± 0.31 mm (Wang et al 37 , AS OCT Visante, pupillary plane), tilt 3.7° ± 1.2° and decentration 0.21 mm ± 0.17 mm (Fus et al 38 , custom software, pupil center), tilt less than 2.4° and decentration less than 0.4 mm (de Castro et al 32 , Pentacam Scheimpflug imaging, pupillary axis), tilt 1.5° and decentration 0.21 mm (Rosales et al 31 , Pentacam Scheimpflug imaging, pupillary axis), tilt 4.4° ± 2.5° (T) and 9.20° ± 6.96° (S) and decentration 0.44 mm ± 0.19 mm (T) and 0.74 mm ± 0.91 mm (S) (Maedel et al 39 , Tabernero's (T) 17 and Schaeffel's (S) 19 Purkinje-meters, pupillary axis). All the mentioned IOL tilt values are smaller than those from our study (both AS OCT and dynamic Purkinje-meter), apart from the Schaeffel's Purkinje-meter values which are higher (9.2° ± 7.0°) and are given relative to the fixation axis as the only ones.…”

“…All the mentioned IOL tilt values are smaller than those from our study (both AS OCT and dynamic Purkinje-meter), apart from the Schaeffel's Purkinje-meter values which are higher (9.2° ± 7.0°) and are given relative to the fixation axis as the only ones. The values of IOL decentration vary considerably across the studies, even if the reference structure is limited to the pupil only -the range of mean values is from 0.17 mm to 0.74 mm [30][31][32][37][38][39] . We assume that different decentrations may depend primarily on different types of intraocular lenses.…”

Tilt and decentration with various intraocular lenses: A narrative review

“…There are several factors contributing to IOL tilt and decentration[ 5 , 6 ]. Among those, the patients’ ocular condition is an important factor affecting IOL position.…”

Analysis of intraocular lens decentration and tilt after femtosecond laser-assisted cataract surgery using swept-source anterior optical coherence tomography

“…Advancements in imaging technologies, such as swept-source optical coherence tomography ( S S-OCT) and 3D OCT image reconstruction, have enabled more accurate assessment and automated quantification of IOL tilt and decentration [ 6 , [12] , [13] , [14] , [15] ]. This facilitates a comprehensive understanding of the spatial relationship between the IOL and the capsular bag, consequently facilitating a deeper exploration of the effects of postoperative decentration and tilt on visual acuity, dysphotopsia, and wavefront aberrations [ [16] , [17] , [18] ].…”