Postoperative astigmatism and axis stability after implantation of the STAAR Toric Implantable Collamer Lens

Rotational Stability, Footplate Position, and Visual Outcomes of Toric Implantable Collamer Lenses in Eyes With Low Vault

PURPOSE

To evaluate the clinical outcomes, rotational stability, and footplate position of the toric Implantable Collamer Lens (TICL) (STAAR Surgical) in eyes with low vault and analyze factors related to rotational stability.

METHODS

This prospective observational study included 59 eyes of 59 patients with insufficient vault (< 250 µm). Postoperative rotation was defined as the difference between the achieved angle and the intraoperative fixation angle, and assessed with a digital anterior segment photograph after full mydriasis at 1 week and 1, 3, and 6 months postoperatively. Ultrasound biomicroscopy was used to determine the ciliary body morphology and position of the footplate. Correlation analysis was employed to identify the risk factors associated with TICL rotation at 6 months postoperatively.

RESULTS

At 6 months postoperatively, the mean central vault was 137.4 ± 61.0 µm (range: 40 to 236 µm), and the mean efficacy and safety indices were 1.04 and 1.15, respectively. The mean manifest refractive astigmatism decreased from -1.67 ± 0.82 diopters (D) preoperatively to -0.43 ± 0.33 D postoperatively, and the mean absolute rotation was 4.50 ± 3.08 degrees (range: 0 to 12.50 degrees). The angle of rotation was correlated with the preoperative spherical power (r = -0.318, P = .014), the average value of TICL footplates position (r = 0.284, P = .029), and postoperative astigmatism (r = -.469, P⩽ .001).

CONCLUSIONS

TICL implantation is predictable, safe, and effective in correcting myopic astigmatism in eyes with low vault. The rotational stability was acceptable and related to the malposition of the footplate and preoperative spherical power. [J Refract Surg. 2024;40(7):e460-e467.].

Artificial intelligence-based refractive error prediction and EVO-implantable collamer lens power calculation for myopia correction

BACKGROUND

Implantable collamer lens (ICL) has been widely accepted for its excellent visual outcomes for myopia correction. It is a new challenge in phakic IOL power calculation, especially for those with low and moderate myopia. This study aimed to establish a novel stacking machine learning (ML) model for predicting postoperative refraction errors and calculating EVO-ICL lens power.

METHODS

We enrolled 2767 eyes of 1678 patients (age: 27.5 ± 6.33 years, 18-54 years) who underwent non-toric (NT)-ICL or toric-ICL (TICL) implantation during 2014 to 2021. The postoperative spherical equivalent (SE) and sphere were predicted using stacking ML models [support vector regression (SVR), LASSO, random forest, and XGBoost] and training based on ocular dimensional parameters from NT-ICL and TICL cases, respectively. The accuracy of the stacking ML models was compared with that of the modified vergence formula (MVF) based on the mean absolute error (MAE), median absolute error (MedAE), and percentages of eyes within ± 0.25, ± 0.50, and ± 0.75 diopters (D) and Bland-Altman analyses. In addition, the recommended spheric lens power was calculated with 0.25 D intervals and targeting emmetropia.

RESULTS

After NT-ICL implantation, the random forest model demonstrated the lowest MAE (0.339 D) for predicting SE. Contrarily, the SVR model showed the lowest MAE (0.386 D) for predicting the sphere. After TICL implantation, the XGBoost model showed the lowest MAE for predicting both SE (0.325 D) and sphere (0.308 D). Compared with MVF, ML models had numerically lower values of standard deviation, MAE, and MedAE and comparable percentages of eyes within ± 0.25 D, ± 0.50 D, and ± 0.75 D prediction errors. The difference between MVF and ML models was larger in eyes with low-to-moderate myopia (preoperative SE >  - 6.00 D). Our final optimal stacking ML models showed strong agreement between the predictive values of MVF by Bland-Altman plots.

CONCLUSION

With various ocular dimensional parameters, ML models demonstrate comparable accuracy than existing MVF models and potential advantages in low-to-moderate myopia, and thus provide a novel nomogram for postoperative refractive error prediction and lens power calculation.

Short-term clinic observation of misalignment and rotational stability after implantable collamer lens implantation

PURPOSE

We aimed to investigate misalignment (tilt and decentration) and rotational stability of the implantable collamer lens V4c 6 months after implantation and to explore the potential risk factors associated with postoperative misalignment and rotation.

METHODS

A total of 36 eyes of 36 patients with high myopia and myopic astigmatism who underwent implantable collamer lens V4c implantation were included in this study. Tilt, decentration, and rotation of the implantable collamer lens were assessed postoperatively at l week, 1 month, 3 months, and 6 months. Correlation analysis was used to identify the potential risk factors for implantable collamer lens tilt, decentration, and rotation at 6 months postoperatively. Higher-order aberration was measured to evaluate the effect of implantable collamer lens misalignment on visual quality at pupil diameters of 4.0 mm and 6.0 mm.

RESULTS

The tilt and decentration at the last follow-up were 2.43 ± 1.35° and 0.278 ± 0.160 mm, respectively. There was a significant positive correlation between tilt and decentration (r = 0.31, P = 0.046). No significant correlation was detected between implantable collamer lens decentration and internal higher-order aberrations (P > 0.05). The degree of implantable collamer lens rotation (3.11 ± 2.00°) was significantly associated with the vault (r =  - 0.422, P = 0.01), while it was positively associated with the preoperative anterior chamber depth (r = 0.36, P = 0.034). No significant correlation was found between postoperative astigmatism and rotation (r =  - 0.07, P = 0.351).

CONCLUSIONS

The implantable collamer lens V4c provides relatively stable misalignment and rotation after implantation. The ICL lens vault is a potential risk factor for postoperative implantable collamer lens rotation. The absolute value of decentration and tilt was relatively small, which showed no correlation with internal higher-order aberration in short-term observation.

[Correction of ametropia with posterior chamber phakic intraocular lens]

Posterior chamber phakic intraocular lens (PIOL) implantation is a widely accepted and performed refractive surgery for correction of moderate and high myopia used when corneal laser ablation procedures are not suitable. This paper analyzes literature data to reveal the advantages and limitations of the technology.

A critical evaluation of longitudinal changes of astigmatism following implantation of toric implantable collamer lens (TICL): a comparison between treated and untreated cases over 4 years

PURPOSE

To evaluate residual astigmatism following correction with toric implantable collamer lens (TICL) (group I) over a period of 4 years and compare with the change of astigmatism in spectacle wearers (group II).

METHODS

Groups I (86 cases implanted with TICL [EVO + Visian ICL, Staar Surgical, Nidau, Switzeland], preop refractive error [sphere and cylinder] - 22.25 DS to - 1.00 DS and - 5.50 DC to - 1.00 DC) and II (80 cases initial refractive error [sphere and cylinder] - 18.00 DS to 0.00 DS and - 7.00 DC to - 1.00 DC) were reviewed annually. Refractive and tomography data were subjected to vector analysis to determine surgically induced astigmatism (SIA), angle of error [Δθ° = angle of target-induced astigmatism (TIA) - angle of SIA], and ΔC [TIA-SIA powers] and total corneal astigmatism (TCA) in group I and induced change in astigmatism (ICA) in group II.

RESULTS

In group I, on all occasions, SIA correlated with TIA (p < 0.05); differences between SIA and TIA means were insignificant and changes in TCA were not correlated with ΔC. Mean (± sd, 95% CI) residual astigmatic powers (RA) in attending group I cases (1-4 years) were - 0.40 DC (0.58, - 0.52 to - 0.28), - 0.40 DC (0.59, - 0.52 to - 0.27), - 0.41 DC (0.58, - 0.54 to - 0.28), and - 0.61 DC (0.74, - 0.82 to - 0.40). In group II, the corresponding ICA powers were - 0.47 DC (0.53, - 0.61 to - 0.32), - 0.49 DC (0.48, - 0.69 to - 0.29), - 0.60 DC (0.40, - 0.76 to - 0.44), and - 0.86 DC (0.71, - 1.19 to - 0.52). Differences between RA and ICA were not significant. Of the group I cases presenting at 1-4 years postop, 23, 18, 16, and 28 had RA powers ≤  - 0.75 DC. Of these 12, 10, 6, and 16 were associated with Δθ° > 5° (ΔC - 0.50 to 0 DC) and 5, 1, 4, and 4 were related to ΔC (Δθ° < 5°).

CONCLUSION

The development of astigmatism after TICL implantation is on par with the natural change in astigmatism in untreated cases. In about 50% of TICL cases presenting with astigmatism ≤  - 0.75 DC, the residual astigmatism could be neutralized by realigning the TICL.

Outcomes and complications of implantable collamer lens for mild to advance keratoconus

PURPOSE

To evaluate the outcome and safety of implantable collamer lens (ICL; (Visian, STAAR Surgical, Monrovia, CA, USA) in mild to advance keratoconus patients with myopia and myopic astigmatism.

METHODS

This retrospective study evaluated all patients who underwent ICL implantation for the management of keratoconus at a tertiary care eye hospital from January 2012 to January 2018. The mean duration of follow-up was 15.3 months (range, 3.13 to 38.97 months). Data were collected on preoperative and postoperative uncorrected distance visual acuity (UDVA) and corrected distance visual acuity (CDVA), refraction was compared, and adverse effects were evaluated.

RESULTS

Thirty-two eyes (32 patients) were evaluated. The median CDVA was 20/30 preoperatively and 20/20 at last follow-up. The median UDVA was 20/25 at last follow-up. Thirteen patients (40.6%) had 20/20 UDVA in comparison to none at baseline. The median spherical equivalent in diopters (D) was -7.875 D (-4.125 to -10.0 D) preoperatively and decreased to -0.3125 D at last follow-up. The median manifest refractive cylinder was 3.00 D (2.25 to 5.25 D) preoperatively and decreased to 1.125 D postoperatively. Cylinder axis rotation of 10° or greater occurred in 3 eyes (9.375%) and required repositioning of the ICL. One patient (3%) developed nonvisually significant anterior subcapsular cataract. One ICL (3.125%) had to be explanted due to residual refractive error and unsatisfactory vision.

CONCLUSION

ICLs are a suitable refractive option for the correction of refractive error associated with stable, nonprogressive keratoconus even in advance cases. However, the risk of ICL rotation and subsequent repositioning remain. Careful patient selection is necessary for achieving good outcomes and mitigating intraoperative and postoperative complications.

Repeated rotation of a toric implantable collamer lens: A case report

INTRODUCTION

Implantable collamer lens have been used widely worldwide, and have been accepted by more and more doctors and patients due to good safety, stability, and effectiveness. However, there is still a problem of crystal rotation. The large angle rotation (over 10°) would weaken the original astigmatism correction effect and even induce irregular astigmatism, seriously affecting the visual quality of patients. Herein, we reported a case who had 2 times of crystal rotations after toric implantable collamer lens (TICL) implantation.

PATIENT CONCERNS

The patient was a 38-year-old man who underwent TICL implantation for the correction of high myopic astigmatism in eyes. He presented a sudden decrease in the visual acuity (VA) of the left eye 4 months after the TICL implantation. The uncorrected visual acuity (UCVA) was 8/20 (refraction, +2.25 -5.25 × 68).

DIAGNOSIS

Rotation of TICL was diagnosed. The toric marks with a rotation of 75° counter-clockwise from the original position were observed.

INTERVENTIONS

The TICL was re-set to the original position, leading to the UCVA of 12/20 in the left eye (refraction, -0.00 -0.75 × 131), with the vaulting of 589 μm. Ten months after the TICL relocation, the patient again presented a sudden decrease in the VA of the left eye, with the UCVA of 2/20 (refraction, +2.25 -5.00 × 66). Again, the toric marks with a rotation of 75° counter-clockwise from the original position was observed, just at the same position as the last rotation. This time, the TICL was removed. The axis and power were recalculated, and a new TICL was implanted, with the rotation of 73° counter-clockwise from the horizontal line of the temporal side.

OUTCOMES

The patient obtained a final UCVA of 12/20 in the left eye (refraction, +0.50 -0.50 × 26), which remained stable in the 6-month follow-up period, with the vaulting of 602 μm.

LESSONS

Rotation is a common complication after TICL surgery. Relocation or replacement of TICL are safe and efficient ways to recover VA due to TICL rotation.

Clinical Effect and Rotational Stability of TICL in the Treatment of Myopic Astigmatism

Purpose

To investigate the clinical outcomes and possible risk factors associated with rotational stability after the implantation of a V4c toric implantable Collamer lens (TICL) for the correction of moderate to high myopic astigmatism.

Methods

A total of 112 eyes of 66 patients with moderate to high myopic astigmatism underwent TICL implantation. All patients were followed up for more than 1 year. The uncorrected and best-corrected visual acuity (UCVA and BCVA), astigmatism and spherical equivalent, intraocular pressure, vault, endothelial cell morphometry, and rotation of the TICL axis were assessed at l day, 1 week, 1 month, 3 months, 6 months, and 12 months postoperatively. Postoperative rotation was defined as the angle between the intended axis and the achieved axis. Regression analysis was used to investigate the possible risk factors for TICL rotation postoperatively.

Results

The mean efficacy index and safety index 12 months postoperatively were 1.03 ± 0.09 and 1.05 ± 0.10, respectively. All patients had the same or better visual acuity than preoperatively. The mean astigmatism value decreased from -1.86 ± 0.79 D preoperatively to -0.37 ± 0.35 D. The mean absolute axis deviation of the TICL at the last follow-up was 2.75 ± 2.04° (range, 0°∼11°). The mean manifest refraction spherical equivalent (MRSE) changed from -9.04 ± 2.67 D preoperatively to -0.67 ± 0.51 D postoperatively. The logistic regression demonstrated that the absolute degree of TICL rotation had a significant association with the fixation angle of the TICL and the size of the lens (P=0.003, P=0.026, resp.).

Conclusion

The results of our study support that TICL implantation is safe, effective, and predictable in the treatment of moderate to high myopic astigmatism, with relatively good postoperative rotational stability.

Polar value analysis of astigmatic change and rotational stability after implantation of V4c toric implantable collamer lens

Background

To evaluate the clinical results and rotational stability of V4c toric implantable collamer lens (TICL, STAAR Surgical Company, Monrovia, CA, USA) in patients with moderate to high myopic astigmatism. Retrospective, interventional case series was performed at Shenzhen Eye Hospital, Shenzhen, Guangdong, China.

Methods

This study enrolled 43 patients (72 eyes) who received TICL implantation to correct myopia and myopic astigmatism. The patients underwent visual and refractive examinations before and 1 month after surgery. Astigmatic changes were estimated using polar value analysis. The difference between the achieved axis and the intended axis at the last follow-up was taken as the rotation of the V4c TICL.

Results

At 1 month postoperatively, the mean safety and efficacy indices were 1.17 and 1.13, respectively. A significant reduction of 8.92±2.58 D was observed in the spherical equivalent refraction (SER), which decreased from −9.29±2.41 D preoperatively to −0.37±0.55 D postoperatively. The astigmatic error of treatment in cylinder format was calculated to 0.50±0.41 @ 15.08° relative to the preoperative stronger meridian at 1 month, postoperatively. At 1 month postoperatively, the mean absolute rotation was 8.30±10.00 degrees (median =5.46 degrees; range, 0.00–58.88 degrees).

Conclusions

TICL could achieve good astigmatic outcomes for correcting moderate to high myopic astigmatism. After TICL implantation, corneal astigmatism remained unchanged. To optimize postoperative astigmatic outcomes in TICL, polar value analysis can be used to build a nomogram.

Safety and efficacy of toric implantable collamer lens V4c model - A retrospective South Indian study

Purpose:

The aim of this study was to evaluate the safety, efficacy, and complications of V4c Toric implantable collamer Lens (TICL) implantation for myopic astigmatism in the south Indian population.

Methods:

In this retrospective observational case series, a total of 109 eyes of 67 patients who underwent V4c TICL implantation (ICL, V4C Staar Surgical, Nidau, Switzerland) between January 2012 and August 2019 were studied with a minimum follow-up period of 6 months (mean 24 months). The main outcome measures were objective and subjective refraction, uncorrected distance visual acuity, corrected distance visual acuity (CDVA), safety, predictability, adverse events, and postoperative complications.

Results:

At 6 months, mean manifest refractive spherical equivalent (SE) decreased from - 10.90 ± 3.7D preoperatively to - 0.02 ± 0.13D postoperatively (P < 0.001) and mean cylinder decreased from - 2.3 ± 1.3 D preoperatively to - 0.04 ± 0.2 D postoperatively (P < 0.001). Postoperatively, SE within ± 0.5 D and ± 1.0 D of attempted correction were achieved in 96.3 (105 eyes) and 100% (109 eyes), respectively. Manifest refractive cylinder within ± 0.5 D and ± 1.0 D of attempted correction were achieved in 97.2 (106 eyes) and 100% (109 eyes), respectively. Sixty-two percent (68 eyes) showed no change in CDVA postoperatively, and no eye had lost lines of CDVA. The safety index was 1.12, and the efficacy index was 1.10. Complications were seen in two eyes (1.8%) due to high postoperative vault requiring secondary surgical interventions.

Conclusion:

V4c TICL is a highly effective, safe, and predictable option in treating myopic astigmatism with excellent improvement in vision and spectacle independence.

Comparison of Toric Implantable Collamer Lens and Toric Artiflex Phakic IOLs in Terms of Visual Outcome: a Paired Contralateral Eye Study

PURPOSE

This study sought to compare the postoperative visual outcomes of toric implantable collamer lens (T-ICL) with toric Artiflex (T-Artiflex) lenses.

DESIGN

Alternating treatment, contralateral eye matched clinical study.

METHODS

This study compared 82 eyes of 41 patients with T-ICL lenses in one eye and toric Artiflex implantation in the contralateral eye to correct myopic astigmatism. Safety, efficacy, predictability, astigmatic vector changes, contrast sensitivity, endothelial cell count, and possible adverse events were assessed at least 12 months postoperatively.

RESULTS

After a mean follow-up of 12 months, the safety index was mean 1.40 ± 0.70 in the T-ICL group and 1.20 ± 0.21 in the T-Artiflex group. Furthermore, their mean efficacy indexes were 1.24 ± 0.42 and 1.08 ± 0.23, respectively (P = .029). A total of 39 eyes (95%) in the T-ICL group and 41 eyes (100%) in the T-Artiflex group were within ±1.00 diopter (D) of emmetropia and 33 eyes (80%) and 34 eyes (83%) were within ±0.5 D of emmetropia, respectively. Vector analysis revealed mean index of success as large as 0.25 ± 0.22 in the T-ICL group and 0.24 ± 0.15 in the T-Artiflex group. Postoperative contrast sensitivities were equal in both groups under mesopic conditions for any given spatial frequency. There was an endothelial loss of 2.18% and 1.95% in the T-ICL and T-Artiflex groups, respectively. There were no significant complications in any of the groups.

CONCLUSIONS

Both lenses showed promising results in terms of safety, efficacy, and predictability for correction of myopic astigmatism. As shown in this paired-eye study, most outcomes were almost identical, and neither of these lenses were clinically superior to the other.

Spontaneous rotation of a toric implantable collamer lens related to abnormal ciliary body morphology: a case report

BACKGROUND

This is a case of spontaneous toric implantable collamer lens (TICL) rotation that occurred twice in the left eye of a patient.

CASE PRESENTATION

A 24-year-old gentleman received TICL implantation for treatment of myopic astigmatism encountered with spontaneous rotation of approximately 90° from its original position. TICL reposition procedure was performed with visual outcome of 20/16. Surprisingly, a re-rotation of TICL occurred. The patient underwent a replacement of non-toric ICL with a larger size after careful re-evaluation with final visual outcome of 20/20. A short and small ciliary process with shallow ciliary sulcus and posteriorly positioned ciliary body was found by Ultrasound Biomicroscopy (UBM).

CONCLUSIONS

The unique morphology of the ciliary body may have a potential association with the vault and instability of implanted ICL. Careful examination of the ciliary body morphology is essential in preoperative evaluation.

Relative position of the central hole after EVO-ICL implantation for moderate to high myopia

Background

This study aimed to evaluate the relative position of the central hole (C_H) of EVO Implantable Collamer Lens (EVO-ICL), the pupil center (C_P), and the corneal center (C_C) after implantation of EVO-ICLs for moderate to high myopia.

Methods

Eighty-nine eyes of forty-seven patients with moderate to high myopia were evaluated. The mean preoperative spherical equivalent (SE) was − 12.58 ± 4.13D. A routine postoperative follow-up was performed within 1 ~ 12 months. Positions of the C_H of EVO-ICLs, the C_P and the C_C were recorded using a slit lamp anterior segment photography system, and their relative distances were calculated with the Visio image analysis software.

Results

All surgeries were performed safely, and no complications were observed in follow-ups 4.3 ± 4.82 months after surgery. At the last follow-up, the safety index (postoperative CDVA/preoperative CDVA) was 1.23 ± 0.48, and the efficacy index (postoperative UDVA/preoperative CDVA) was 1.08 ± 0.31. The C_H in 85 eyes (95.51%) was superior to the C_C, with 47.19% (42/89) on the temporal side and 48.31% (43/89) on the nasal side. The C_H in 84 eyes (94.38%) was located on the temporal side of the C_P, with 56.18% (50/89) superior and 38.2% (34/89) inferior to the C_P. The C_P of 85 eyes (95.51%) was superior on the nasal side of the C_C. On the defined x-axis, the average distance from the C_H to C_C was significantly shorter than the average distance from the C_P to C_C (p < 0.001).

Conclusions

An imperfect match between the central hole of EVO-ICLs and the pupil center does not necessarily indicate ICL dislocation. Compared to the pupil center, the position of the central hole of EVO-ICL is closer to the corneal center.

Evaluation of postoperative toric intraocular lens alignment with anterior segment optical coherence tomography

We describe the use of a simple tool to evaluate the postoperative alignment of toric intraocular lenses (IOLs). The entire anterior segment is scanned using anterior segment optical coherence tomography and analyzed with an internal dedicated tool. A topographic map is displayed along with an anterior segment image, including a linear axis marker centered on the corneal apex. The marker can be rotated until it is aligned with the line connecting the IOL marking dots, precisely reproducing the IOL astigmatic axis, which is measured in angle degrees. The value of the IOL astigmatic axis is compared with the value of the astigmatic axis shown in real time on the same screen in the topographic map. Evaluating the alignment of a toric IOL axis simultaneously with the topographic astigmatic axis eliminates the potential errors that result from head tilting and strictly correlates with the astigmatic correction achieved.

Current Trends in Modern Visual Intraocular Lens Enhancement Surgery in Stable Keratoconus: A Synopsis of Do's, Don'ts and Pitfalls

Keratoconus is a relatively common ectatic, non-inflammatory corneal disorder that involves gradual visual deterioration through progressive alteration of the shape of the cornea. The corneal thinning, irregular astigmatism and higher order aberrations that occur as the disease progresses pose major challenges in the visual rehabilitation of such patients. This paper summarizes the current literature regarding the results of visual enhancement procedures in patients with stable keratoconus treated with standalone anterior or posterior chamber phakic intraocular lens implantation and monofocal, toric or multifocal toric intraocular lens implantation following phacoemulsification for age-related cataract extraction or refractive lens exchange.

Implantable collamer lens with central hole: 3-year follow-up

Purpose

To evaluate the long-term predictability, stability, safety, and efficacy of the V4c Visian implantable collamer lens (ICL) with central hole to correct myopia.

Patients and methods

One hundred and eighty-four eyes of 92 patients were evaluated during 3 years after implantation of the V4c ICL. The refraction, uncorrected distance visual acuity, best-corrected distance visual acuity, IOP, endothelial cell count, vault, and adverse effects were evaluated every 12 months during the whole follow-up.

Results

The mean spherical equivalent dropped from -8.30±2.98 D preoperatively to −0.37±0.47 D at 36 months post-surgery, with 91.8% eyes being within ±1.00 D of emmetropia. With respect to the astigmatic components J0 and J45, 98.4% and 99.5% of eyes, respectively, were within ±0.50 D of the desired refraction. At 36 months, 78.8% of eyes had no change in the Snellen lines of best-corrected distance visual acuity, while 8.7% gained one line and 6.5% gained two or more lines; mean safety and efficacy indexes were 1.03 and 0.90, respectively. Mean endothelial cell count was 2,742±340 cells/mm² before and 2,663±366 cells/mm² at 36 months post-surgery. Mean IOP reduced from 13.7±1.9 mmHg preoperatively to 12.8±1.7 mmHg at 36 months post-surgery. Mean vault varied from 409±196 µm at 12 months to 349±165 µm at 36 months.

Conclusion

The visual and refractive outcomes were very good and highly stable throughout the follow-up period, indicating that this ICL model may be predictable, stable, safe, and effective to correct myopia in the long term.

Rotational Stability and Visual Outcomes of V4c Toric Phakic Intraocular Lenses

PURPOSE

To investigate the clinical outcomes and rotational stability following implantation of V4c toric implantable collamer lenses (ICLs) (STAAR Surgical Company, Monrovia, CA) and to analyze the factors that influence rotational stability.

METHODS

In this prospective observational case series, the authors analyzed the visual outcomes and rotational stability in 52 eyes of 52 patients immediately and 3 and 6 months after implantation. Postoperative rotation was defined as the angle between the adjusted axis and alignment axis. Central vaulting of the ICL was measured in a non-accommodative state using Visante optical coherence tomography (Carl Zeiss Meditec, Jena, Germany). Vector analysis of refractive astigmatism was performed. Regression analysis was used to investigate the association between the degree of rotation 6 months postoperatively and the associated variables.

RESULTS

The mean efficacy index and safety index 6 months postoperatively were 1.35 ± 0.19 and 1.38 ± 0.22, respectively. In vector analysis, the magnitude of error was -0.20 diopters (D), indicating slight undercorrection. Absolute degree of rotation was 2.81° ± 1.87° immediately after the operation and 3.75° ± 2.92° and 3.87° ± 3.07° at 3 and 6 months postoperatively, respectively (P = .009). Bonferroni-adjusted post-hoc comparison showed that the absolute degree of rotation immediately after the operation was significantly smaller than that after 3 (P = .043) and 6 (P = .023) months, with barely any change after 3 months. No explanatory variable relevant to the absolute degree of rotation was discovered.

CONCLUSIONS

The V4c toric ICL is predictable, safe, and effective in correcting low and high levels of astigmatism, showing relatively good postoperative rotational stability. [J Refract Surg. 2018;34(7):489-496.].

A comparison of visual outcome and rotational stability of two types of toric implantable collamer lenses (TICL) : V4 versus V4c

PURPOSE

To compare the efficacy and rotational stability after implantation of two types of toric implantable collamer lenses (Toric ICL™(TICL);V4 and V4c, STAAR Surgical Co.).

STUDY DESIGN

Retrospective case series.

METHODS

This retrospective study evaluated total 48 eyes of 48 patients who underwent the implantation with V4 and V4c TICL with a central hole; A twenty-four eyes of 24 patients with V4 TICL and 24 eyes of 24 patients with V4c TICL with a central hole. Visual acuity, manifest refraction, and intraocular pressure were evaluated before and after surgery. Rotational stability (disparity between the intended axis and achieved axis) was assessed in both groups using digital anterior segment photographs, and vector analysis was also performed.

RESULTS

Uncorrected visual acuity improved in both groups without significant difference (P = .111). There were no statistical differences between two groups in postoperative SE and cylindrical errors (P = .067 and .384, respectively). The mean value of rotation was 4.17±3.31° and 3.39±2.36° in the V4 and V4c TICL groups, respectively without significant difference (P = .364). Vector analysis of astigmatic correction showed no significant diffrence between two groups.

CONCLUSION

V4 and V4c TICL have similar efficacy with regard to visual acuity and refractive outcomes and rotational stability.

Implantable collamer lens in a case of corneal scar with anisometropic amblyopia in an adult: an expanded indication

A 35-year-old man, a unilateral high myope with corneal scarring, presented for evaluation. He had a stromal scar that started temporally, traversed along the pupillary zone partially and extended across the horizontal diameter of the cornea. The Descemet's membrane appeared intact even though the scar was extending into deep stroma towards the nasal end, as seen in the optical coherence tomography image. The patient had an uncorrected distance visual acuity (UDVA) of 4/60 OD, which improved with a refraction of -9.0 DS/-1.50 DC at 15 to 6/18p and 6/6p OS. He underwent an uneventful toric implantable collamer lens (ICL) implantation of -15.0 D/-2.0 D at 102 after preoperative yttrium-aluminium-garnet (YAG) laser iridotomy in the right eye. The postoperative UDVA and corrected distance visual acuity for the right eye were 6/12 and 6/9p (with a refraction of +0.50 D/-0.50 D at 85), respectively. The corneal scar and topography were stable. This case reports an expanded indication for toric ICL in cases with corneal scar/opacity but good spectacle corrected visual acuity.

Evaluation of the toric implantable collamer lens for simultaneous treatment of myopia and astigmatism

Myopic astigmatism is a prevalent condition that can be treated with spectacles, contact lenses, or laser refractive surgery. However, these treatment options have functional limitations at higher levels of refractive error. The toric implantable collamer lens is designed to treat a broad range of refractive error, generally up to -18 diopters with +1 to +6 diopters of astigmatism. Approval for a more limited treatment range of up to 15 diopters of myopia with +1 to +4 diopters of astigmatism is being sought in the US, where this device has not yet received marketing approval. Surgical correction of high-myopic astigmatism can be life-altering and allow people to participate in activities that were not previously feasible because of visual limitations. The toric implantable collamer lens is implanted behind the iris and in front of the natural crystalline lens. With earlier lens designs, it was necessary to create an iridectomy or iridotomy to prevent pupillary block. The newest toric implantable collamer lens model has a small central hole that is not visually noticeable. This eliminates the need to create a hole in the iris, thereby enhancing the safety of the procedure.

The visual and functional impacts of astigmatism and its clinical management

PURPOSE

To provide a comprehensive overview of research examining the impact of astigmatism on clinical and functional measures of vision, the short and longer term adaptations to astigmatism that occur in the visual system, and the currently available clinical options for the management of patients with astigmatism.

RECENT FINDINGS

The presence of astigmatism can lead to substantial reductions in visual performance in a variety of clinical vision measures and functional visual tasks. Recent evidence demonstrates that astigmatic blur results in short-term adaptations in the visual system that appear to reduce the perceived impact of astigmatism on vision. In the longer term, uncorrected astigmatism in childhood can also significantly impact on visual development, resulting in amblyopia. Astigmatism is also associated with the development of spherical refractive errors. Although the clinical correction of small magnitudes of astigmatism is relatively straightforward, the precise, reliable correction of astigmatism (particularly high astigmatism) can be challenging. A wide variety of refractive corrections are now available for the patient with astigmatism, including spectacle, contact lens and surgical options.

CONCLUSION

Astigmatism is one of the most common refractive errors managed in clinical ophthalmic practice. The significant visual and functional impacts of astigmatism emphasise the importance of its reliable clinical management. With continued improvements in ocular measurement techniques and developments in a range of different refractive correction technologies, the future promises the potential for more precise and comprehensive correction options for astigmatic patients.

Stability of axis and patient satisfaction after toric implantable collamer lens implantation for myopic astigmatism

Objectives: To assess the stability of axis and patient satisfaction after toric visian implantable collamer lens (TICL) implantation for moderate to high myopic astigmatism.

Methods: Total 33 eyes of 21 consecutive patients who underwent implantation of TICL for the correction of moderate to high myopic astigmatism were recorded and a minimum follow-up of six months was performed. The deviation of axis of TICL was detected from one week to six months postoperatively. The evaluation of the visual functions was done by the same clinician at six months after surgery.

Results: The mean refractive cylinder decreased from -2.48±0.91 diopters (D) preoperatively to -0.54±0.25D and -0.50±0.19D at one week and six months after surgery respectively. Mean changes in astigmatism from one week to six months after surgery was 0.03±0.17D. The mean deviation of axis of TICL from one week to six months postoperatively was 2.48±1.25°(range,1°~ 6°) and no TICL required secondary repositioning. 14.3% patients felt difficult about the middle distant visual function (Reading Computer Screen). Evaluations of other visual functions were positive or very positive.

Conclusions: Six months after implantation of the TICL, it showed slightly axis rotation and high satisfaction about the visual functions.

Correction of postkeratoplasty ametropia in keratoconus patients using a toric implantable Collamer lens

PURPOSE

To evaluate the efficacy and safety of a toric implantable Collamer lens (Visian TICL®) for correction of high postkeratoplasty ametropia in patients with keratoconus. 


METHODS

Seven eyes of 7 keratoconus patients postkeratoplasty (5 M, 2 F; mean age 34.1±5.9 years, range 28-44) unable to wear glasses or contact lenses were included in the study. A foldable phakic posterior chamber Collamer toric lens was injected through a standard 3.0-mm clear corneal temporal incision. Uncorrected distance visual acuity (UCDVA, logMAR), best-corrected distance visual acuity (BCDVA, logMAR), spherical refraction, cylindrical refraction, and refractive spherical equivalent (RSE) were measured preoperatively and postoperatively. Postoperative adverse events were recorded. 


RESULTS

. The mean follow-up was 12.8±8.8 months (range 4-30). A significant (p<0.01) improvement was observed postoperatively in mean UCDVA (1.18±0.4 vs 0.2±0.1), spherical refraction (-5.89±3.43 vs 0.53±0.75), cylindrical refraction (-4.39±0.75 vs -1.74±0.84), and RSE (-8.09±3.77 vs -0.33±0.54). The BCDVA changes were not significant (0.09±0.11 vs 0.05±0.08). All patients gained ≥5 lines of UCDVA (average 7.6±1.9 lines). The number of patients with UCDVA ≥6/12 (0.3 logMAR) increased after surgery (0% vs 87.5%; p<0.01), while the number of patients with BCDVA ≥6/12 was unchanged (100% vs 100%; NS), with 0% (0/7) of patients losing ≥2 BCDVA lines. No complications were observed postoperatively. 


CONCLUSIONS

Toric implantable Collamer lens was safe and effective in correcting postkeratoplasty myopia and astigmatism in keratoconus patients.

Outcomes and possible risk factors associated with axis alignment and rotational stability after implantation of the Toric implantable collamer lens for high myopic astigmatism

AIM

To assess the visual outcomes and possible risk factors associated with axis alignment and rotational stability after implantation of Toric implantable collamer lens (TICL) for the correction of high myopic astigmatism.

METHODS

In this prospective, nonrandomized clinical study, 54 consecutive eyes of 29 patients with high myopic astigmatism received TICL implantation. To evaluate postoperative axis deviation from the intended axis, a digital anterior segment photograph was taken. The ultrasound biomicroscopy(UBM) was used to observe footplate-position.

RESULTS

After mean follow-up of 8.6 months, mean manifest refractive cylinder (MRC) decreased 79.3% from (-1.88±1.49)D preoperatively to (0.39±0.61)D postoperatively. MRC within 1.00 D occurred in 68.5% (37/54) of eyes, whereas 48.1% (26/54) had MRC within 0.50 D. Mean manifest refraction spherical equivalent (MRSE) changed from (-12.08±4.22)D preoperatively to (-0.41±0.61)D postoperatively. Uncorrected binocular vision of 20/20 or better occurred in 72.2% (39/54) of patients compared with binocular best-corrected visual acuity (BCVA) of 20/20 or better in 44.4% (24/54) preoperatively. The mean difference between intended and achieved TICL axes was (6.96±8.37)°. Footplates of TICLs were in the ciliary sulcus in 22 eyes (46.3%), below the ciliary sulcus in 32 eyes (53.7%). The angle of TICL rotation had significant correlation with the footplates-position (t=2.127; P=0.045) and the postoperative TICL vaulting (r=-0.516; P=0.000).

CONCLUSION

The results of our study further support the safety, efficacy and predictability of TICL for the correct high myopic astigmatism. The footplate-position of TICL and vault value should be taken into consideration as two possible risks factors for TICL rotation.

Factors affecting rotation of a posterior chamber collagen copolymer toric phakic intraocular lens

PURPOSE

To evaluate the correlation between postoperative rotation of the toric Implantable Collamer Lens phakic intraocular lens (pIOL) and associated factors.

SETTING

Nagoya Eye Clinic, Nagoya, Japan.

DESIGN

Case series.

METHODS

The toric pIOL axis was analyzed by calculating the ocular internal cylinder power and axis from the total refractive cylinder and corneal astigmatism using vector analysis (Jaffe and Clayman method). The correlation between the toric pIOL rotation over 6 months postoperatively and the associated factors (ie, age, preoperative manifest refractive sphere, preoperative manifest spherical equivalent, mean keratometric power, axial length, toric pIOL intraoperative fixation angle, postoperative toric pIOL vault [distance between toric pIOL and anterior surface of crystalline lens], toric pIOL spherical power) were evaluated.

RESULTS

The mean age of the 34 patients (58 eyes) was 35.7 years ± 6.5 (SD). The mean rotation 6 months postoperatively was 4.82 ± 6.98 degrees (range 0.0 to 47.2 degrees). The intraoperative toric pIOL fixation angle and postoperative toric pIOL rotation were significantly correlated (Spearman rank correlation: P=.0096 and R(2) = 0.1140; multiple logistic regression analysis: P=.009). In the 1 eye with significant rotation (47.2 degrees), the toric pIOL was exchanged for a larger toric pIOL.

CONCLUSIONS

A small toric pIOL rotation occurred during the 6-month follow-up. One cause of rotation could be the intraoperative fixation angle of the toric pIOL. A toric pIOL with a minimum intraoperative fixation angle should be used to prevent postoperative rotation.

Astigmatism correction: Laser in situ keratomileusis versus posterior chamber collagen copolymer toric phakic intraocular lens implantation

PURPOSE

To compare the stability and predictability of astigmatism correction between toric phakic intraocular lens (pIOL) implantation and laser in situ keratomileusis (LASIK).

SETTING

Nagoya Eye Clinic, Nagoya, Japan.

DESIGN

Comparative case series.

METHODS

Consecutive patients who had Implantable Collamer Lens pIOL implantation or LASIK were divided into 3 subgroups according to the amount of refractive cylinder correction (low, 0.00 to 1.25 diopters [D]; moderate, 1.50 to 2.75 D; high, ≥ 3.00 D). Manifest refraction was measured preoperatively and 1, 3, 6, and 12 months postoperatively. Based on these data, the predictability and stability of the refractive cylinder correction, error of the refractive cylinder correction, and error of the refractive cylinder correction axis were evaluated.

RESULTS

The study comprised 338 eyes (196 patients) in the toric pIOL group and 351 eyes (202 patients) in the LASIK group. In the moderate cylinder subgroup, more eyes were corrected within ± 0.50 D of the postoperative refractive cylinder in the LASIK group (132 eyes [91%]) than in the toric pIOL group (111 eyes [79%]). In the high refractive cylinder subgroup, the error of the refractive cylinder correction in the LASIK group was significantly higher than in the toric pIOL group (P=.032). The postoperative manifest refractive cylinder did not change in either group during the follow-up period.

CONCLUSIONS

The stability of the refractive cylinder after toric pIOL implantation was as high as after LASIK. Although predictability in the LASIK group was higher than in the toric pIOL group in eyes with moderate refractive cylinder, the toric pIOL group had higher predictability than the LASIK group in eyes with high refractive cylinder.

Simple and accurate alignment of toric intraocular lenses and evaluation of their rotation errors using anterior segment optical coherence tomography

PURPOSE

To describe a new method of alignment of toric intraocular lenses (IOLs) and evaluation of their rotation errors using anterior segment optical coherence tomography (AS-OCT).

METHODS

Twenty-nine eyes of 22 patients who had cataract extraction and implantation of an acrylic toric IOL were included. The new AS-OCT method was used for the alignment of toric IOLs and evaluation of their rotation errors. These rotation errors were evaluated and compared with those measured using the internal map of a wavefront aberrometer.

RESULTS

The mean rotation error ± standard deviation (SD) of the toric IOLs evaluated by AS-OCT was 3.2 ± 2.2° and 3.2 ± 2.4° at 1 week and 1 month after surgery, respectively. The mean difference in the reference axis between the visits was 1.8 ± 2.1°. The mean difference between the rotation errors of the alignment axes measured by AS-OCT and the internal map was 2.5 ± 1.9° (P = 0.037).

CONCLUSION

The current method is clinically useful not only for the accurate alignment of toric IOLs but also for evaluating their rotation errors.

Risk factor evaluation for cataract development in patients with low vaulting after phakic intraocular lens implantation

PURPOSE

To evaluate the occurrence of cataract in eyes with low vaulting after phakic intraocular lens (pIOL) implantation for myopia and suggest guidelines for such cases.

SETTING

Samsung Medical Center, Seoul, Korea.

DESIGN

Cross-sectional study.

METHODS

Eyes with low Implantable Collamer Lens pIOL vaulting (<250 μm) were followed 1, 3, and 6 months as well as 1, 2, 3, and 4 years postoperatively. Frequency and time to cataract development were evaluated. Risk factors for cataract development were assessed using logistic regression analysis. Cutoff values for differentiating eyes at higher risk for cataract development were evaluated using Fisher exact and chi-square tests.

RESULTS

Cataract developed in 8 (30.8%) of 26 eyes (6 of 20 patients) a mean of 18.7 months ± 10.1 (SD) postoperatively. Risk factors that were significant for cataract formation included lower vaulting (mean 42.4 ± 34.0 μm versus 141.4 ± 82.2 μm; odds ratio [OR], 1.05), older age (mean 42.6 ± 7.3 versus 34.9 ± 6.9 years; OR, 1.22), and higher preoperative spherical equivalent (SE) (mean -17.1 ± 4.4 diopters [D] versus -10.7 ± 2.7 D; OR, 1.64). The optimum cutoff values were 51.7 μm, 45 years, and -14.00 D (P=.0095, P=.0367, and P=.0342 respectively).

CONCLUSION

In cases of low pIOL vaulting, close follow-up should be considered when central vaulting is less than 52 μm, patient age is more than 45 years, or the preoperative SE is greater than -14.00 D because these factors increase the risk for cataract.

Spontaneous Rotation of a Toric Implantable Collamer Lens

We present a case of toric implantable collamer lens (TICL) spontaneous rotation in a patient with myopic astigmatism. A 23-year-old female underwent TICL implantation. Preoperative uncorrected visual acuity (UCVA) was 20/800 and 20/1200, respectively, with -7.75 -4.25 × 0° and -8.25 -5.25 × 180°. The left eye achieved an UCVA of 20/30. After 3 months of successful implantation of TICL in the left eye, the patient presented with a sudden decrease in visual acuity in the left eye. UCVA was 20/100 with a refraction of +2.50 -4.50 × 165°. We observed the toric marks with a 30° rotation from the original position and decided to reposition the TICL, obtaining a final UCVA of 20/25, which remained stable at 6 months' follow-up. TICL can present a considerable rotation that compromises visual acuity. The relocation of TICL is a safe and effective procedure to recover visual acuity due to significant spontaneous TICL rotation.

Clinical outcomes of posterior chamber toric phakic intraocular lens implantation for the correction of high myopic astigmatism in eyes with keratoconus: 6-month follow-up

BACKGROUND

To assess the early clinical outcomes of toric implantable collamer lenses (toric ICL™, STAAR Surgical) for the correction of high myopic astigmatism with keratoconus.

METHODS

This study evaluated 27 eyes of 14 patients with spherical equivalents of -10.11 ± 2.46 D (mean ± standard deviation) and astigmatism of -3.03 ± 1.58 D who underwent toric ICL implantation for mild keratoconus. Before, and 1, 3 and 6 months after surgery, we assessed the safety, efficacy, predictability, stability, and adverse events of the surgery.

RESULTS

LogMAR uncorrected visual acuity (UCVA) and LogMAR best spectacle-corrected visual acuity (BSCVA) were -0.09 ± 0.16 and -0.15 ± 0.09 respectively, 6 months after surgery. The safety and efficacy indices were 1.12 ± 0.18 and 1.01 ± 0.25. At 6 months, 85% and 96% of the eyes were within ±0.5 and ±1.0 D respectively of the targeted correction. Manifest refraction changes of 0.00 ± 0.35 D occurred from 1 week to 6 months. No vision-threatening complications occurred during the observation period.

CONCLUSIONS

Toric ICL implantation was good in all measures of safety, efficacy, predictability, and stability for the correction of spherical and cylindrical errors in eyes with early keratoconus throughout the 6-month follow-up period, suggesting its viability as a surgical option for the treatment of such eyes.

Comparison of the toric implantable collamer lens and bioptics for myopic astigmatism

PURPOSE

To compare results between toric implantable collamer lens (TICL) implantation and bioptics (ICL and excimer laser ablation) for the correction of myopic astigmatism.

METHODS

A retrospective evaluation was performed in 29 eyes (20 patients) with TICL implantation and 26 eyes (17 patients) treated with bioptics. For eyes treated with bioptics, corneal ablation was performed at 1.5 to 5 months (mean 2.56 months) after ICL implantation by laser epithelial keratomileusis in 17 eyes, LASIK in 8 eyes, and photorefractive keratectomy in 1 eye. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity, refraction, adverse events, safety, and efficacy were assessed preoperatively and 1, 6, and 12 months postoperatively.

RESULTS

At 1 month postoperatively, UDVA in the TICL group was significantly higher than in the bioptics group (P=.02). However, the difference in UDVA at 12 months was not significant. At 12 months, mean spherical equivalent refraction was 0.33±0.21 diopters (D) in the TICL group and 0.29±0.41 D in the bioptics group (P=.07). Mean astigmatic error was higher in the TICL group (-0.42±0.32 D) than in the bioptics group (-0.32±0.38 D) (P=.10). In the bioptics group, the mean refractive cylinder at 12 months decreased from that reported at 6 months because of retreatment performed in two eyes. Safety and efficacy were not statistically different between groups. One eye with a TICL was treated to correct TICL decentration. Two crystalline lens opacities were observed after bioptics.

CONCLUSIONS

This study demonstrates that TICL implantation provides reliable visual outcomes similar to bioptics. The advantages of TICL implantation are a more stable visual outcome and the elimination of laser treatments and their inherent risks.

Visual and optical performance before and after rotation of a misaligned STAAR Toric Implantable Collamer Lens

PURPOSE

To document the use of the NIDEK OPD-Scan II/Station as a monitoring tool and clinical aid in the evaluation and re-rotation of a misaligned STAAR Toric Implantable Collamer Lens (TICL).

METHODS

A 22-year-old man underwent bilateral TICL implantation. Emmetropia was achieved in the left eye after TICL implantation; however, the right eye showed residual compound myopic astigmatism. Both eyes were evaluated using the OPD-Scan II/Station, and re-rotation of the TICL in the right eye was planned using the internal wavefront and corneal topography maps. The remaining residual error after re-rotation was treated using photorefractive keratectomy (PRK).

RESULTS

The left eye showed excellent axis alignment and optical quality. The right eye showed a difference of 8 degrees to 10 degrees in axis of orientation and an under-calculation of the lens power, which resulted in poor optical quality. After rotation of the lens and PRK, emmetropia was achieved and the patient reported resolution of symptoms. Higher order aberrations were reduced by 0.535 microm and the modulation transfer function increased 42% compared to initial TICL implantation.

CONCLUSIONS

Internal and corneal surface aberrometry allowed proper evaluation and precise realignment of a TICL. The objective assessment of the internal astigmatism, optical quality, and visual performance aids in planning complicated surgical cases that require combination surgery to restore visual quality.

Axis alignment and rotational stability after implantation of the toric implantable collamer lens for myopic astigmatism

PURPOSE

To assess axis alignment and stability of the Toric Implantable Collamer Lens (TICL; STAAR Surgical Co) over time.

METHODS

Thirty-five consecutive eyes of 19 patients received the TICL for treatment of myopic astigmatism. Manifest refraction spherical equivalent (MRSE) and manifest refractive cylinder were measured preoperatively and at 3 months postoperatively. The axis alignment of the TICL was measured using the internal OPD map obtained with the OPD-Scan II (NIDEK Co Ltd).

RESULTS

Mean refractive cylinder was reduced from 2.80+/-1.45 diopters (D) preoperatively to 0.63+/-0.75 D at 3 months postoperatively; MRSE was -7.61+/-4.02 D preoperatively and -0.14+/-0.38 D at 3 months. Mean absolute value of the measured axis misalignment from baseline (day 1) to 1 month was 2.90+/-2.11 degrees and from 1 month to 3 months was 4.6+/-11.2 degrees. Mean absolute value of the measured changes in axis misalignment from baseline to 3 months was 2.68+/-2.11 degrees (after excluding one eye that required repositioning due to TICL rotation). At 3 months postoperatively, 96.8% (30/31) eyes had <or=8 degrees and 90.3% (28/31) had <or=5 degrees of axis misalignment.

CONCLUSIONS

The TICL showed minimal axis misalignment after implantation and remained stable 3 months postoperatively.