Determinants of intraocular lens tilt and decentration after cataract surgery

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

Objective

To evaluate and compare the magnitude of intraocular lens (IOL) decentration and tilt following conventional and femtosecond laser-assisted cataract surgery (FLACS) using swept-source anterior optical coherence tomography (SS-OCT).

Methods

In this retrospective observational study, we enrolled patients who underwent conventional cataract surgery or FLACS with the implantation of hydrophobic 1-piece monofocal IOL. The magnitude of IOL decentration and tilt were measured using SS-OCT. Visual acuity, intraocular pressure, spherical equivalent, axial length, contrast sensitivity, and satisfaction questionnaire were evaluated before and one-month post-surgery. Additionally, postoperative internal cylinder measurements were obtained using a wavefront aberrometer. Correlation factors between each parameter and IOL decentration or tilt were analyzed.

Results

This study included 100 eyes from 100 patients. Mean IOL decentration and tilt were 0.21 ± 0.13 mm and 5.01 ± 1.49°, respectively. Conventional cataract surgery (versus FLACS, P = 0.001) and male sex (versus female, P = 0.047) were significantly correlated with higher postoperative decentration. Preoperative lens diameter (P < 0.001), preoperative lens tilt (P = 0.007), and preoperative intraocular pressure (P = 0.027) were correlated with higher postoperative tilt. Fifty eyes that underwent FLACS demonstrated mean postoperative decentration of 0.21 ± 0.13 mm and tilt of 4.64 ± 1.48°. Compared with the conventional surgery group, the FLACS group significantly differed in postoperative decentration (0.30 ± 0.12 mm, P < 0.001) but not in tilt (5.03 ± 1.35°, P = 0.173). Postoperative visual acuity did not significantly differ between the two groups.

Conclusion

Patients who underwent FLACS demonstrated better IOL decentration and tilt than those who underwent conventional cataract surgery one-month post-surgery. However, differences in IOL decentration and tilt did not affect postoperative visual acuity.

An analysis of the factors involved in IOL decentration after phacoemulsification using CASIA 2 anterior segment optical coherence tomography

PURPOSE

To evaluate the magnitude of IOL transversal shift (ITS) after phacoemulsification and to analyse the factors contributing to IOL decentration and ITS.

METHODS

94 consecutive patients who underwent cataract surgery and IOL implantation was enrolled. Each patient underwent anterior segment optical coherence tomography with CASIA 2 (Tomey, Nagoya, Japan) to assess crystalline lens decentration, thickness and diameter seven days preoperatively and at one and sixty days postoperatively. Univariate and multivariate linear regression analysis were performed to evaluate the determinants of ITS and final decentration.

RESULTS

The preoperative crystalline lens diameter was associated with the ITS and with the IOL final decentration. A positive association between the final IOL decentration and the first post-surgical day decentration was found (p < 0.0001).

CONCLUSION

Greater crystalline lens diameter was associated with greater decentration and with greater ITS. Day-one IOL decentration seems to be the main determinant of final IOL decentration.

Effect of decentration and tilt on the in vitro optical quality of monofocal and trifocal intraocular lenses

PURPOSE

To evaluate and compare the effect of decentration and tilt on the optical quality of monofocal and trifocal intraocular lenses (IOL).

METHODS

Optical quality of a monofocal IOL (AcrySof IQ SN60WF; Alcon Laboratories, Inc., USA) and a trifocal IOL (AcrySof IQ PanOptix; Alcon Laboratories, Inc., USA) was assessed using an in vitro optical bench (OptiSpheric IOL R&D; Trioptics GmbH, Germany). At apertures of 3.0 mm and 4.5 mm, modulation transfer function (MTF) at spatial frequency of 50 lp/mm, MTF curve and the United States Air Force (USAF) resolution test chart of the two IOLs were measured and compared at their focus with different degrees of decentration and tilt. Optical quality at infinity, 60 cm and 40 cm and the through-focus MTF curves were compared when the two IOLs were centered at apertures of 3.0 mm and 4.5 mm. Spectral transmittance of the two IOLs was measured by the UV-visible spectrophotometer (UV 3300 PC; MAPADA, China).

RESULTS

The SN60WF and the PanOptix filtered blue light from 400 to 500 nm. Both IOLs at the far focus and the PanOptix at the intermediate focus showed a decrease in optical quality with increasing decentration and tilt. The PanOptix demonstrated enhanced optical quality compared to the previous gradient at the near focus at a decentration range of 0.3-0.7 mm with a 3.0 mm aperture, and 0.5 mm with a 4.5 mm aperture, whereas other conditions exhibited diminished optical quality with increasing decentration and tilt at the focus of both IOLs. When the two IOLs were centered, the SN60WF had better optical quality at infinity, while the PanOptix had better optical quality at 60 cm and 40 cm defocus. The optical quality of the SN60WF exceeded that of the PanOptix at far focus, with a 3 mm aperture decentration up to 0.7 mm and a 4.5 mm aperture decentration up to 0.3 mm; this observation held true for all tilts, irrespective of aperture size. As both decentration and tilt increased, the optical quality of the SN60WF deteriorated more rapidly than that of the PanOptix at the far focal point.

CONCLUSIONS

The SN60WF showed a decrease in optical quality with increasing decentration and tilt. Optical quality of the PanOptix at the near focus increased in some decentration conditions and decreased in some conditions, while it showed a decrease at the other focuses with increasing decentration. While tilt only had a negative effect on optical quality. When both IOLs were centered, the PanOptix provided a wider range of vision, while the SN60WF provided better far distance vision. At the far focus, the SN60WF has better resistance to tilt than the PanOptix, but the optical quality degrades more quickly when decentered and tilted.

Repeatability of Pentacam-derived intraocular lens decentration measurements and the level of agreement with OPD-Scan III: A prospective observational case series

PURPOSE

This study aimed to assess the repeatability of intraocular lens (IOL) decentration measurements obtained through Pentacam, based on corneal topographic axis (CTA) and pupillary axis (PA), and to evaluate the level of agreement between Pentacam and OPD-Scan III devices in measuring IOL decentration.

METHODS

In this prospective observational case series, three measurements were performed with Pentacam to evaluate the repeatability of the measurements. The analysis included the calculation of the mean and standard deviations (SD), conducting a repeated measures analysis of variance (rANOVA), and determining an intraclass correlation coefficient (ICC) to assess the repeatability of the measurements. Moreover, Bland-Altman analysis was employed to assess the agreement between Pentacam and OPD-Scan III devices in measuring IOL decentration. IOL decentration measurements were obtained with respect to both CTA and PA.

RESULTS

A total of 40 eyes from 40 patients were analyzed. The rANOVA revealed no significant difference among three consecutive measurements of IOL decentration obtained with Pentacam. The mean SD of all parameters ranged from 0.04 mm to 0.07 mm. With CTA as the reference axis, the ICC values for Pentacam measurements of IOL decentration were 0.82 mm for the X-axis, 0.76 mm for the Y-axis, and 0.82 mm for spatial distance. When using PA as the reference axis, the corresponding ICC values were 0.87, 0.89, and 0.77, respectively. The 95% limits of agreement for all IOL decentration measurements were wide when comparing Pentacam and OPD-Scan III.

CONCLUSIONS

Pentacam demonstrated high repeatability in measuring IOL decentration with respect to both CTA and PA. However, due to poor agreement between Pentacam and OPD-Scan III measurements, caution should be exercised when using data interchangeably between the two devices.

Novel diagnostic indicators for acute angle closure secondary to lens subluxation based on anterior segment and lens parameters

Purpose: To explore stable and sensitive indicators for clinical diagnosis of acute angle closure (AAC) secondary to lens subluxation (LS) through quantitative analysis of CASIA 2 imaging.Design: A prospective cross-sectional study.

Methods

Setting: Clinical practice.Participants: 23 patients with unilateral acute angle closure secondary to lens subluxation and 23 cataract patients without lens subluxation were recruited. Lens subluxation was confirmed by ultrasound biomicroscope diagnosis. The contralateral eyes without LS served as fellow control group. The cataract eyes without LS were enrolled in blank control group.Intervention: Participants underwent ophthalmologic examinations including slit-lamp biomicroscope, best corrected visual acuity, intraocular pressure, central corneal thickness measurement, axial length, gonioscopy, ultrasound biomicroscope and 360-degree anterior chamber and crystalline lens scan protocols of CASIA 2 system.Main outcome measures: Automated circumferential anterior segment and lens morphological parameters under anterior segment optical coherence tomography were analyzed via three-dimensional analysis.

Results

Significant differences were found in the front and back radius of the lens, the front and back radius of steep curvature of the lens, lens thickness, lens decentration, lens diameter, iris-trabecular contact (ITC) index, ITC area, anterior chamber depth (ACD), lens vault (LV), and iris volume between LS and controls. Among these parameters, LV, the anterior radius of steep curvature of the lens and ACD demonstrated the highest prediction power (AUC = 0.87, 0.89, and 0.86, respectively). The prediction power of tilt/axis was much higher in the Gaussian Naive Bayes model (AUCs = 0.90) than in the logistic model (AUCs = 0.74). Combination of LV_mean, LV_std, tilt and tilt axis in Gaussian Naive Bayes model presented as most stable and excellent diagnostic markers for AAC secondary to LS (AUCs = 0.98).

Conclusions

The combination of markers including lens tilt and lens vault in the mathematic model facilitate clinical work as it not only provides novel diagnostic indications and possible prompt treatment for AAC secondary to lens subluxations, but also enhances our understanding of the pathogenic role of zonulopathy in angle closure glaucoma.

Postoperative intraocular lens stability following cataract surgery with or without primary posterior continuous curvilinear capsulorrhexis: an intra-individual randomized controlled trial

PURPOSE

To evaluate the effect of primary posterior continuous curvilinear capsulorrhexis (PPCCC) on the positional stability of IOLs.

METHODS

This study is a prospective intra-individual comparative randomized controlled trial including 31 patients (62 eyes). Eyes of the same patient were randomly assigned to the PPCCC group (18 right eyes and 13 left eyes) or group without PPCCC (NPCCC group). Eyes in both groups were implanted with a one-piece foldable hydrophobic acrylic IOL via routine cataract surgery. Patients in the PPCCC group underwent additional manual PPCCC before IOL implantation. Examinations were performed 1 day, 1 week, 1 month and 3 months postoperatively. IOL tilt (x, y), decentration (x, y), anterior chamber depth (z) and refractive prediction error data were collected and analyzed with Pentacam.

RESULTS

Postoperatively, the range of IOL position change over 3 months in PPCCC group was comparable to NPCCC group, which indicated smaller value in every tilt and decentration index. PPCCC eyes showed comparable tilt and decentration with NPCCC eyes in this study endpoint: mean tilt (x, y), decentration (x, y) and anterior chamber depth (ACD) were 1.04 ± 0.56°, 0.90 ± 0.64°, 0.239 ± 0.140 mm, 0.233 ± 0.133 mm and 4.01 ± 0.32 mm, respectively, in the PPCCC group vs. 1.09 ± 0.76°, 1.10 ± 0.82°, 0.252 ± 0.153 mm, 0.244 ± 0.155 mm and 4.01 ± 0.38 mm, respectively, in the NPCCC group. Refractive prediction error in the PPCCC group demonstrated a mild hyperopic shift vs. the NPCCC group (0.13 ± 0.50 vs. 0.05 ± 0.39; p = 0.208), and corrected distance visual acuity (CDVA) did not differ between the two groups (0.027 ± 0.014 vs. 0.059 ± 0.185; p = 0.377).

CONCLUSIONS

Comparable IOL tilt, decentration, ACD and refractive prediction error were observed in PPCCC eyes with that underwent routine cataract surgery. Little IOL position fluctuation and good visual acuity were shown in PPCCC group over time.

TRAIL REGISTRATION

The study was registered at the Chinese Clinical Trial Register Center on May 27th, 2020 (protocol code ChiCTR2000033304, 27/05/2020).

Building prediction models of clinically significant intraocular lens tilt and decentration for age-related cataract

PURPOSE

To explore the risk factors and construct nomogram models to predict the risks of clinically significant intraocular lens (IOL) tilt and decentration after cataract surgery in patients with age-related cataract.

SETTING

Zhongshan Ophthalmic Center, Guangzhou, China.

DESIGN

Prospective cohort study.

METHODS

207 patients (207 eyes) who underwent phacoemulsification combined with IOL implantation were enrolled in the study. Casia2 was used to measure the tilt and decentration of crystalline lenses and IOLs before and 3 months after surgery. Univariate and multivariate logistic regression analyses were used to determine the risk factors of clinically significant IOL tilt and decentration, and nomogram prediction models were constructed according to the results of the multivariate logistic regression analysis.

RESULTS

Two hundred and seven patients were included in analysis. 24 eyes (11.59%) and 16 eyes (7.73%) had clinically significant IOL tilt and decentration at 3 months after cataract surgery. Multivariate logistic regression analysis revealed that preoperative crystalline lens tilt and decentration were the risk factors for clinically significant IOL tilt (odds ratio [OR], 3.519, P < .001) and decentration (OR, 410.22, P = .001), respectively. Axial length was another association factor for clinically significant IOL decentration (OR, 2.155, P = .019). The risk models demonstrated good calibrations and discriminations for the predictions of clinically significant IOL tilt (receiver operating characteristic [ROC] area = 0.833, cutoff value = 6.5) and decentration (ROC area = 0.757, cutoff value = 0.08).

CONCLUSIONS

The good performances of our models suggested that they may be useful risk prediction tools for postoperative IOL tilt and decentration. The measurement of preoperative crystalline lens tilt and decentration should be one of the routine examinations before cataract surgery, especially for toric and multifocal IOLs.

Current State of the Art and Next Generation of Materials for a Customized IntraOcular Lens according to a Patient-Specific Eye Power

Intraocular lenses (IOLs) are commonly implanted after surgical removal of a cataractous lens. A variety of IOL materials are currently available, including collamer, hydrophobic acrylic, hydrophilic acrylic, PHEMA copolymer, polymethylmethacrylate (PMMA), and silicone. High-quality polymers with distinct physical and optical properties for IOL manufacturing and in line with the highest quality standards on the market have evolved to encompass medical needs. Each of them and their packaging show unique advantages and disadvantages. Here, we highlight the evolution of polymeric materials and mainly the current state of the art of the unique properties of some polymeric systems used for IOL design, identifying current limitations for future improvements. We investigate the characteristics of the next generation of IOL materials, which must satisfy biocompatibility requirements and have tuneable refractive index to create patient-specific eye power, preventing formation of posterior capsular opacification.

Repositioning of in-the-bag Dislocated Intraocular Lenses: A Randomized Clinical Trial Comparing Two Surgical Methods

INTRODUCTION

The aim of this study was to evaluate intraocular lens (IOL) tilt, IOL-induced astigmatism (IIA), refractive change, and impact of capsular fibrosis on IOL position after scleral fixation of dislocated IOL using two methods: ab externo scleral suture loop fixation (group A) and a modification, embracing the continuous curvilinear capsulorhexis (group B).

METHODS

In this prospective randomized clinical trial conducted at St. Erik Eye Hospital, 117 patients with dislocated IOL were randomized to group A (n = 61) or B (n = 56). Patients with ordinary pseudophakia (n = 60) served as controls. IOL tilt was measured three-dimensionally with anterior segment optical coherence tomography (AS-OCT).

RESULTS

The median IOL tilt was similar with both methods (A: 7.8°; B: 8.3°; p = 0.51) but higher than in ordinary pseudophakia (5.4°; p < 0.001). Both groups showed a myopic shift, p < 0.001. In cases without capsular fibrosis, the median IOL tilt was 15.5° in group A (n = 7) and 7.0° in group B (n = 5), p = 0.19. For each degree of IOL tilt, IIA increased by 0.075 D (p < 0.001). IOL position could be measured with AS-OCT in all patients given that the IOL was visible in the pupil.

CONCLUSION

After IOL fixation surgery, IOL tilt is higher than in normal pseudophakia. A study involving more patients without capsular fibrosis could clarify whether IOL position is better with method B in this subgroup. IAA is low, but myopic shift is common. AS-OCT is useful for IOL tilt assessment after IOL fixation surgery.

Presbyopia-correcting performance and subjective outcomes of a trifocal intraocular lens in eyes with different axial lengths: A prospective cohort study

Purpose

To compare the presbyopia-correcting performance, visual quality, satisfaction and life quality after implantation of a diffractive trifocal intraocular lens (IOL) in eyes with different axial lengths (AL).

Methods

This prospective cohort study enrolled patients with implantation of a trifocal IOL. Manifest refraction, uncorrected and distance-corrected visual acuity at different distances, contrast sensitivity, aberrations and IOL decentration were measured 3 months after surgery. Spectacle independence, adverse photic phenomena, overall satisfaction and life quality were assessed with a questionnaire.

Results

This study included 61 eyes of 61 patients: 16 eyes in the short AL group, 28 eyes in the control group and 17 eyes in the long AL group. Postoperatively, the prediction error (PE) of spherical equivalent showed a difference (P = 0.002). The uncorrected near visual acuity in the long AL group was higher (P = 0.047). Although a higher IOL decentration was obtained in the long AL group (P = 0.034), no significant difference was found in contrast sensitivity and aberrations (all P &gt; 0.05). In the questionnaire, patients in the long AL group showed a relatively lower spectacle independence at near distance (P = 0.060) and had difficulties in near activities, mental health and role in daily life (P = 0.003, 0.021, and 0.033). However, no significant difference was observed in overall satisfaction (P = 0.124).

Conclusion

With detailed preoperative evaluation, the trifocal IOL provided satisfactory visual outcomes for patients with different AL. AL had a certain influence on predictability and IOL decentration. And for patients with long AL, the inadaptability to the near focal point might become an important problem.

Risk factors associated with intraocular lens decentration after cataract surgery

PURPOSE

To identify risk factors associated with intraocular lens (IOL) decentration after uneventful phacoemulsification with IOL implantation.

DESIGN

A prospective cohort study METHODS: All patients underwent a general ophthalmologic examination. One month postoperatively, the magnitude and orientation of IOL decentration relative to the visual axis center were assessed using an OPD-Scan III aberrometer, and the vertical and horizontal decentration values were determined. Univariate and multivariate linear regression analyses were performed to evaluate the association between the IOL decentration and ocular biometric parameters.

RESULTS

In total, 143 eyes of 143 patients were enrolled. The mean decentration magnitude was 0.27±0.15 mm, and the decentration axis appeared at any orientation, with no orientation tendency. The horizontal and vertical decentration were -0.02±0.22 mm and 0.01±0.22 mm, respectively. Multivariate regression analysis showed that the white-to-white distance (WTW) and the magnitude of angle α were positively associated with the decentration magnitude (P<0.001, adj. R²=0.121), the horizontal angle κ and horizontal angle α were positively associated with the horizontal decentration (P<0.001, adj. R²=0.209), and the anterior chamber depth (ACD) and vertical angle κ were positively associated with the vertical decentration (P<0.001, adj. R²=0.152).

CONCLUSIONS

The IOL decentration magnitude was greater in patients with a larger WTW and a larger angle α, the horizontal decentration was greater in patients with a larger horizontal angle κ and a larger horizontal angle α, and the vertical decentration was greater in patients with a deeper ACD and a larger vertical angle κ. In these patients, premium IOLs should be implanted cautiously.

Influence of anterior capsulorhexis shape, centration, size, and location on intraocular lens position: finite element model

PURPOSE

To evaluate the influence of anterior capsulorhexis shape, dimension, and eccentricity on intraocular lens (IOL) position.

SETTING

Laboratory investigation.

DESIGN

Computational model.

METHODS

A finite element model of the human crystalline lens capsule and zonule was created and the anterior capsule opened to simulate centered and decentered circular and elliptic rhexis. The model calculated capsular bag stress, IOL rotation, tilt, decentration, and vaulting, related to both capsular landmarks (absolute) and a reference IOL position defined as that obtained with a 5.0 mm circular and centered rhexis.

RESULTS

Mean von Mises stress along the IOL major z-axis was significantly higher than that along the perpendicular x-axis in all cases (P < .001), both at the equator and at the rhexis edge. Stress at the equator was always greater than that at the rhexis edge (P < .001) regardless of the rhexis shape and position. As rhexis eccentricity increased, the stress difference between the z- and x-axes increased. Absolute IOL tilt (range 10-1 to 10-7 degrees), decentration (10-3 to 10-7 mm), rotation (10-2 to 10-3 degrees), and vaulting (10-1 mm) were negligible from an optical standpoint, but all of them were significantly greater for decentered rhexis (both round and elliptic) compared with centered (P < .05).

CONCLUSIONS

Anterior capsulorhexis irregularity and/or eccentricity increase IOL tilt, decentration, rotation, and vaulting in a numerically significant but optically negligible way. Von Mises stress is much greater at the capsular bag equator compared with the rhexis edge and highly asymmetrically distributed in all cases. Stress asymmetry may influence postoperative biologic processes of capsular bag shrinking and further IOL tilting or decentration.

Preoperative Factors Affecting Visual Acuity Following the Implantation of Diffractive Multifocal Intraocular Lenses

PURPOSE

To investigate the preoperative factors affecting visual acuity after the implantation of a diffractive multifocal intraocular lens.

METHODS

This study evaluated 774 eyes of 774 patients who underwent cataract surgery with TECNIS Multifocal ZLB00 lens (Johnson & Johnson Surgical Vision) implantation. Anterior segment optical coherence tomography (CASIA2; Tomey Corporation) was performed as a part of the preoperative eye examination. Sex, age, axial length, and CASIA2 parameters, such as crystalline lens diameter and lens tilt relative to the corneal topographic axis, were investigated. The eyes considered were classified into good (20/20 or better) or poor (worse than 20/20) far vision groups based on corrected distance visual acuity, and good (20/25 or better) or poor (worse than 20/25) near vision groups based on distance-corrected near visual acuity, respectively. Preoperative characteristics of both groups were compared to determine factors affecting postoperative visual acuity.

RESULTS

Multivariate logistic regression analysis revealed that older age (P < .001), a short axial length (P = .010), and a large lens tilt (P < .001) were associated with poor near vision. There was no significant difference between the two far vision groups. There was a significant negative correlation between lens tilt and axial length (r = -0.513, P < .001).

CONCLUSIONS

The results of this study suggest that age, axial length, and lens tilt to the corneal topographic axis may predict poor visual acuity after the implantation of a diffractive multifocal intraocular lens. Eyes with a short axial length tended to have a large degree of lens tilt and should be considered particularly carefully. [J Refract Surg. 2021;37(10):674-679.].

The efficacy of ultrasonic emulsification with IOL implantation in patients with primary angle-closure glaucoma combined with cataract

PURPOSE

This study aimed to investigate the clinical efficacy of ultrasonic emulsification plus IOL implantation in patients with primary angle-closure glaucoma and cataract.

METHODS

The clinical data of 81 patients (91 eyes) with primary angle-closure glaucoma comorbid with cataract in our hospital were retrospectively analyzed and divided into two groups based on surgical modality. Group A (n=40, 45 eyes) underwent trabeculectomy and group B (n=41, 46 eyes) underwent ultrasonic emulsification and IOL implantation. The success rate, best corrected visual acuity, intraocular pressure, anterior chamber depth, anterior chamber angle, visual field, cornea's endothelial cell count, complications, and patient satisfaction were compared between the two groups.

RESULTS

The surgical success rate in group B was 97.83%, significantly higher than 86.67% in group A (P < 0.05); Compared with group A, group B had higher best-corrected visual acuity and lower intraocular pressure (P < 0.05) as well as higher central and peripheral anterior chamber depths at 3 months postoperatively (P < 0.05); After surgery, group A had significantly lower postoperative cornea's endothelial cell count (P < 0.05). Compared with group A, MS was higher and MD was lower in group B at 3 months postoperatively (P < 0.05); the complication rate in group B was 8.70%, lower than 28.89% in group A (P < 0.05).

CONCLUSION

The clinical efficacy of ultrasonic emulsification combined with IOL implantation is remarkable in patients with primary angle-closure glaucoma and cataract, which is conducive to improving postoperative visual acuity, lowering intraocular pressure, increasing the atrial angle, and improving visual field defects. It is also with high safety, but has little effect on cornea's endothelial cell count.