Correlative Comparison of Three Ocular Axes to Tilt and Decentration of Intraocular Lens and Their Effects on Visual Acuity

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.

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.

A comparative study of transscleral sutured intraocular lens fixation and sutureless flanged intraocular lens fixation

BACKGROUND

To compare the intraocular lens (IOL) tilt and decentration and visual outcomes of transscleral sutured IOL fixation and sutureless flanged IOL fixation. To investigate the influence of IOL tilt and decentration on internal higher-order aberrations (HOAs) in these two techniques.

METHODS

Patients who received transscleral sutured or sutureless flanged IOL fixation procedures were included in this prospective, non-randomized, comparative study. Corrected distance visual acuity (CDVA) was measured at baseline and at every postoperative visit for 12 months. IOL tilt and decentration were measured using a second-generation anterior segment optical coherence tomography (Casia2) and internal HOAs were measured using iTrace Visual Function Analyzer at 3 months postoperatively.

RESULTS

The study included 27 eyes from the transscleral sutured IOL fixation group and 26 eyes from the sutureless flanged IOL fixation group. There was no significant difference in CDVA between the two groups at all time points. The two groups did not differ in refractive difference from the predicted value, corneal endothelial cell loss, IOL tilt, IOL decentration, internal astigmatism or internal HOAs. Vertical IOL decentration significantly correlated with total internal optical aberration (r = 0.288, P = 0.036), total internal HOA (r = 0.440, P = 0.001), internal coma (r = 0.348, P = 0.001), vertical internal coma (r = 0.388, P = 0.004), average height of modulation transfer function (r = - 0.364, P = 0.007) and Strehl ratio (r = - 0.297, P = 0.031). Horizontal IOL decentration significantly correlated with horizontal internal coma (r = 0.312, P = 0.023).

CONCLUSIONS

Transscleral sutured IOL fixation and sutureless flanged IOL fixation had similar IOL positions and visual outcomes. IOL decentrations correlated with internal HOAs and thus should be avoided.

ICL Postimplantation Decentration and Tilt in Myopic Patients with Primary Iridociliary Cysts

Purpose

To observe the decentration and tilt of implantable collamer lens (ICL) as well as possible visual effects postimplantation in primary iridociliary cysts.

Methods

The present investigation was a retrospective cohort study. All 48 patients (91 eyes) who underwent ICL surgery at the Center of Refraction Surgery of Tianjin Medical University Eye Hospital between July 2018 and May 2020 were split into two groups based on the absence or presence of primary iridociliary cysts established by ultrasonic biological microscopy (UBM) examination. Intraocular pressure (IOP), corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), anterior chamber angle (ACA), anterior chamber volume (ACV), and anterior chamber depth (ACD) were recorded preoperatively and postoperatively at 1, 6, and 12 months. Additionally, we performed an analysis of the ICL vault, decentration, and tilt using a rotating Scheimpflug Oculus Pentacam camera system at 1, 6, and 12 months after surgery.

Results

No serious complications were observed. Significant postoperative improvement (P < 0.05) of UDVA was established in the two studied groups; however, we did not observe statistically significant intergroup differences (P > 0.05) throughout the entire research period. In each group, the preoperative ACA, ACV, and ACD were statistically significantly reduced (P < 0.05), but no such decrease was established between their postoperative values (P > 0.05). We observed no statistical differences between both groups with regard to their values of IOP, ACA, ACV, ACD, ICL vault, ICL decentration, and tilt at 1, 6, and 12 months after surgery. Similarly, no statistically significant within-group correlation (P > 0.05) of the decentration of ICL and the tilt and the CDVA values was established.

Conclusion

No postimplantation effect of ICL with a central hole on vision was established in myopia patients with primary iridociliary cysts, within certain limits of ICL decentration and tilt values.

Influence of IOL Weight on Long-Term IOL Stability in Highly Myopic Eyes

Purpose

This study aimed to investigate the influence of intraocular lens (IOL) weight on long-term IOL stability in highly myopic eyes.

Materials and Methods

A total of 205 highly myopic cataract eyes of 205 patients implanted with the MC X11 ASP (Group A, 86 eyes) or 920H IOL (Group B, 119 eyes) were included in this retrospective study. Eyes were divided into 3 subgroups according to the IOL power: low (≥-5 to <5 D), medium (≥5 to <14 D), and high (≥14 D) IOL power. At 3 years after surgery, IOL decentration and tilt, high-order aberrations, and anterior capsular opening (ACO) area were measured. The influence of IOL weight on long-term IOL stability was evaluated.

Results

Group B had a significantly greater IOL weight than Group A (Group B vs. Group A: 28.31 ± 2.01 mg vs. 25.71 ± 4.62 mg, P < 0.001). Correspondingly, Group B presented significantly greater overall and inferior decentration than Group A, especially for low and medium IOL power (all P < 0.05). In both groups, overall and vertical decentration was significantly correlated with IOL weight (all P < 0.05). Group B showed a significantly greater ACO area than Group A (P < 0.05). Multivariate analysis showed that decentration in Group A was affected by IOL weight, while decentration in Group B was affected by IOL weight and AL.

Conclusions

Higher IOL weight may lead to greater long-term IOL decentration in highly myopic eyes, while the haptic design may play a role in anterior capsular contraction.

Evaluation of Intraocular Lens Tilt and Decentration in Congenital Ectopia Lentis by the Pentacam Scheimpflug System

Purpose

The purpose of this study was to quantify the characteristics of the tilt and decentration of the IOL after trans-scleral suture fixation surgery in congenital ectopia lentis (CEL) patients.

Methods

The clinical characteristics of 70 CEL patients at Zhongshan Ophthalmic Center in China were retrospectively analyzed. The tilt and decentration of intraocular lens (IOL) were measured by using a Pentacam and compared between different axial length (AL) subgroups. The correlation between IOL tilt, decentration, and ocular characteristics was investigated using Spearman's correlation analysis.

Results

The postoperative IOL position of CEL patients was mainly located nasally inferiorly. The average tilt of the IOL in CEL patients was less than 7° (for temporal: 2.21 ± 1.53°, for nasal: −1.84 ± 2.04°, for superior: 2.22 ± 2.18°, and for inferior: −1.70 ± 1.62°), and the average decentration of the IOL in CEL patients was larger than 0.4 mm (for temporal: 0.49 ± 0.38 mm, for nasal: −0.69 ± 0.46 mm, for superior: 0.72 ± 0.58 mm, and for inferior: −0.68 ± 0.54 mm). The decentration of CEL patients in the AL ≥ 26 subgroup was greater than those with AL < 24 mm and AL 24 to 26 mm subgroups (for superior: 0.72 ± 0.28 mm vs. 0.46 ± 0.25 mm and 0.48 ± 0.22 mm, all P < 0.05; for inferior: -0.94 ± 0.56 mm vs. −0.44 ± 0.26 mm and -0.44 ± 0.46 mm, all P < 0.05). IOL decentration was positively correlated with AL (for superior: r = 0.44, P=0.019; for inferior: r = 0.54, P=0.006). IOL tilt was positively correlated with AL on the superior side (r = 0.38, P=0.041).

Conclusions

The extent of IOL decentration after trans-scleral suture fixation was great in CEL patients, and the IOL decentration in CEL patients was significantly associated with AL.

Stability of Various Types of Aspheric Intraocular Lenses After Implantation: A One-Year Retrospective Study

Objective

The aim of the present study was to evaluate the stability of four different types of aspheric intraocular lenses (IOLs) after implantation.

Methods

This retrospective study included 124 eyes implanted with four different types of aspheric IOLs including a one-piece four-loop fixed hydrophilic acrylic IOL, a one-piece flat fixed acrylic IOL, a one-piece two-loop fixed acrylic IOL, and a three-piece two-loop fixed silicone IOL. IOL decentration, tilt, and ocular coma-like aberration (coma) at one-week, one-month, three-month, and one-year time points were evaluated postoperatively.

Results

IOL decentration, tilt, and coma in the AO, 36A, IQ, and KS-AiN implantation groups were statistically significantly different one week and one year postoperatively (p < 0.01). There were significant differences between each of the pairs of groups (p < 0.01), except for coma between the AO and 36A implantation groups one week postoperatively (p > 0.05). When comparing the different time points (ie, one week, one month, three months, and one year postoperatively), IOL decentration, tilt, and coma were significantly different in each group (p < 0.05). IOL decentration, tilt, and coma in each group increased over the period from one week to one year postoperatively. A positive linear correlation was observed between IOL decentration or tilt and coma one year postoperatively (p < 0.01).

Conclusion

One-piece multi-point fixed acrylic IOLs demonstrate better stability when compared with three-piece two-point fixed silicone IOLs. IOL decentration, tilt, and coma increase gradually over time. Ocular coma-like aberrations are influenced by the stability of IOLs.

Effect of Intraocular Lens Tilt and Decentration on Visual Acuity, Dysphotopsia and Wavefront Aberrations

Tilt and decentration of intraocular lenses (IOL) may occur secondary to a complicated cataract surgery or following an uneventful phacoemulsification. Although up to 2–3° tilt and a 0.2–0.3 mm decentration are common and clinically unnoticed for any design of IOL, larger extent of tilt and decentration has a negative impact on the optical performance and subsequently, the patients’ satisfaction. This negative impact does not affect various types of IOLs equally. In this paper we review the methods of measuring IOL tilt and decentration and focus on the effect of IOL tilt and decentration on visual function, in particular visual acuity, dysphotopsia, and wavefront aberrations. Our review found that the methods to measure the IOL displacement have significantly evolved and the available studies have employed different methods in their measurement, while comparability of these methods is questionable. There has been no universal reference point and axis to measure the IOL displacement between different studies. A remarkably high variety and brands of IOLs are used in various studies and occasionally, opposite results are noticed when two different brands of a same design were compared against another IOL design in two studies. We conclude that <5° of inferotemporal tilt is common in both crystalline lenses and IOLs with a correlation between pre- and postoperative lens tilt. IOL tilt has been noticed more frequently with scleral fixated compared with in-the-bag IOLs. IOL decentration has a greater impact than tilt on reduction of visual acuity. There was no correlation between IOL tilt and decentration and dysphotopsia. The advantages of aspheric IOLs are lost when decentration is >0.5 mm. The effect of IOL displacement on visual function is more pronounced in aberration correcting IOLs compared to spherical and standard non-aberration correcting aspherical IOLs and in multifocal versus monofocal IOLs. Internal coma has been frequently associated with IOL tilt and decentration, and this increases with pupil size. There is no correlation between spherical aberration and IOL tilt or decentration. Although IOL tilt produces significant impact on visual outcome in toric IOLs, these lenses are more sensitive to rotation compared to tilt.