Implantable contact lens for moderate to high myopia: relationship of vaulting to cataract formation

Immediate versus delayed sequential bilateral ICL implantation: A retrospective comparison of vault height and visual outcomes

PURPOSE

To compare the visual outcomes and risks of suboptimal vault-related complications between immediate sequential bilateral ICL surgery (ISBICLS) and delayed sequential bilateral ICL surgery (DSBICLS).

DESIGN

A retrospective cohort study.

METHODS

Patients who underwent bilateral ICL implantation between November 2014 and December 2021 at the Eye and ENT Hospital of Fudan University (Shanghai, China) were included and divided into two groups: (1) ISBICLS: both eye surgeries performed on the same day, and (2) DSBICLS: second eye surgery performed < 7 days following the first one. Propensity score matching (PSM) was performed to compare the visual outcomes. Multivariable logistic regression models were used to estimate the odds ratios (ORs) of the suboptimal vaults.

RESULTS

Finally, 10,985 eyes were included. After PSM, 204 first surgery eyes and 162 s surgery eyes with complete postoperative data were matched. The safety and efficacy indices did not statistically differ between groups (all > 1.00), except that ISBICLS first surgery eyes achieved better efficacy index than DSBICLS group (1.03 ± 0.26 vs. 1.08 ± 0.23, P = 0.034). Excessive vault was observed in eight (4.06 %) ISBICLS first eyes, one (0.50 %) DSBICLS first eye, and none in the second surgery eye in either group. An insufficient vault was observed in one second eye and one DSBICLS second eye. We found no evidence of differences in the rate of excessive vault (OR = 0.831, 95 % CI: 0.426-1.622, P = 0.588) or insufficient vault (OR = 0.609, 95 % CI:0.062-5.850, P = 0.668).

CONCLUSION

ISBICLS provided safety, efficacy, and refraction predictability comparable to DSBICLS without increasing the risk of suboptimal vault-related complications.

Ten-year follow-up of posterior chamber phakic intraocular lens with central port design in patients with low and normal vault

PURPOSE

To assess the clinical outcomes and postoperative complications of the implantable collamer lens (ICL) with a central port throughout 10 years of follow-up in patients with low and normal vault.

SETTING

Fernández-Vega Ophthalmological Institute, Oviedo, Spain.

DESIGN

Retrospective and comparative case series.

METHODS

This study included eyes that underwent a V4c ICL implantation with 10 years of follow-up. The eyes were divided into 2 groups according to the vault at 1 year postoperatively: vault <250 μm and between 250 μm and 800 μm. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), intraocular pressure (IOP), endothelial cell density (ECD), vault, complications, and secondary surgeries were analyzed.

RESULTS

37 and 90 eyes were enrolled in the low and normal-vault groups, respectively. No differences in UDVA, CDVA, and refraction were found between the groups over 10 years of follow-up. No cases developed ICL-induced anterior subcapsular opacity over the follow-up period. 2 (5.4%) and 8 (8.9%) eyes in the low and normal-vault groups, respectively, required ICL exchange. 1 (2.8%) and 2 (2.2%) eyes in the low and normal-vault groups, respectively, required excimer laser to correct residual refractive error. The IOP remained stable throughout the 10-year follow-up. The loss in ECD from that preoperatively to 10 years postoperatively was 3.8% and 4.5% in the low and normal-vault groups, respectively ( P = .4). No pigment dispersion glaucoma or other vision-threatening complications were reported.

CONCLUSIONS

This study shows good long-term outcomes of the V4c ICL, supporting that the central hole provides safety to the procedure and prevents the potential risk associated with low vault.

Implantable Collamer Lens Procedure Planning: A Review of Global Approaches

More than 2 million implantable collamer lenses (ICLs) have been implanted worldwide. With a central port to improve aqueous flow through the ICL, the latest iteration of this phakic intraocular lens (pIOL) has been shown to have stable outcomes with very low rates of adverse events. However, correct planning and ICL size selection continue to be important to achieve an optimal vault. Shallow or excessive vaults are not complications in and of themselves but may increase the risk of complications. Historically, surgeons have relied on measurements of anterior chamber depth (ACD) and manual, caliper-measured white-to-white (WTW) distance to select the ICL size. New diagnostic and imaging technologies such as optical coherence tomography (OCT) and ultrasound biomicroscopy (UBM) provide additional opportunities for visualization and measurement of the intraocular dimensions involved in phakic intraocular lens implantation, including sulcus-to-sulcus (STS) and angle-to-angle (ATA) diameters. This paper reviews various approaches to ICL planning and sizing that have been published in the peer-reviewed literature, all of which produce acceptable results for predicting vault and size selection. Surgeons may also want to identify a methodology for patient evaluation and ICL size selection that best aligns with their personal preferences, diagnostic technology, and familiarity with analytical optimization tools.

A review of posterior chamber phakic intraocular lenses

PURPOSE OF REVIEW

Posterior chamber phakic intraocular lenses (pIOLs) are increasing in popularity as a viable alternative to laser refractive surgery. The purpose of this review is to evaluate the recent updates to pIOLs and to assess the advancements and safety of the procedure.

RECENT FINDINGS

Accurate lens sizing is the key determinant to suitable vault prediction, advancements to sizing formulae including the use of very high frequency (VHF) digital ultrasound and the application of artificial intelligence and machine learning has led to improved vault prediction and safety. The introduction of the central aquaport has been shown to reduce the formation of cataract and is now adopted in most myopic pIOLs. Recently published studies have demonstrated that pIOLs have an excellent safety profile with no increased risk of retinal detachment or endothelial cell loss. Advancements have led to the introduction of extended depth of focus pIOLs for the correction of presbyopia, further research is required to evaluate the efficacy of new lens designs.

SUMMARY

pIOL surgery is experiencing traction with improved lens design and increased lenses choices such as larger optical zone and presbyopic options. Accuracy of implantable collamer lens sizing is paramount to the safety and clinical outcomes, greater predictability is likely to encourage more posterior chamber pIOL users due to fewer sizing related complications.

The rate of vault changes after ICL V4c implantation and its correlation with anterior segment parameters

Purpose

To investigate the rate of vault changes after implantation of ICL V4c and the correlation with anterior segment parameters.

Methods

A total of 64 eyes were studied from the 37 myopic subjects recruited. CASIA2 was used to record the vault at 1 week, 1 month, 3 months and 6 months after the operation as well as the preoperative anterior segment parameters including pupil diameter, lens vault, anterior chamber depth, anterior chamber width, iris area (IA), iris thickness, angle opening distance, angle recess area, trabecular iris space area, and trabecular iris angle. The rates of vault change in different time intervals were compared and the correlations between the rates and anterior segment parameters were analyzed. P < 0.05 was considered statistically significant.

Results

The rate of vault decrease was -19.53 ± 111.28 μm/month between 1 week and 1 month, -19.90 ± 29.71 μm/month between 1 month and 3 months and -4.25 ± 18.10 μm/month between 3 months and 6 months; hence the rate was shown to slow down significantly from 3 months post-operation (P = 0.024). The average rate of vault changes showed a significant positive correlation with IA (R2 = 0.140, F = 4.980, P = 0.01). No significant correlation was found with other anterior segment parameters (all P > 0.05).

Conclusion

The rate of decreasing vault significantly slowed down from 3 months post-operation. A larger IA may imply a lower decreasing rate of vault change.

Three-Dimensional Quantitative Description of the Implantable Collamer Lens in the Ocular Anterior Segment of Patients With Myopia

PURPOSE

To describe the 3-dimensional (3D) location of the implantable collamer lens (ICL) quantitatively in the posterior ocular chamber of patients with myopia.

DESIGN

Cross-sectional study.

METHODS

To obtain visualization models before and after mydriasis, an automatic 3D imaging method based on swept-source optical coherence tomography was created. Parameters like the ICL lens volume (ILV), the tilt of the ICL and crystalline lens, the vault distribution index, and topographic maps were evaluated to describe the ICL location. Using a paired sample t test and the Wilcoxon signed rank test, the difference between nonmydriasis and postmydriasis conditions was compared.

RESULTS

The study investigated 32 eyes from 20 patients. The 3D central vault did not differ significantly before (P = .994) or after mydriasis (P = .549) compared with the 2D central vault. After mydriasis, the 5-mm ILV decreased by 0.85 mm2 (P = .016), and the vault distribution index increased significantly (P = .001). The ICL and the crystalline lens exhibited tilt (nonmydriasis: ICL total tilt 3.78 ± 1.85 degrees, lens total tilt 4.03 ± 1.53 degrees; postmydriasis: ICL total tilt 3.84 ± 1.56 degrees, lens total tilt 4.09 ± 1.64 degrees). The phenomenon of asynchronous tilt of the ICL and lens was found in 5 eyes, leading to the spatially asymmetric distribution of the ICL-lens distance.

CONCLUSION

The 3D imaging technique provided exhaustive and reliable data for the anterior segment. The visualization models offered multiple perspectives on the ICL in the posterior chamber. Before and after mydriasis, the intraocular ICL position was described by the 3D parameters.

Comparison of Dynamic Vault Changes Following Implantation of Two Different Models of Phakic Intraocular Lenses

PURPOSE

To compare the dynamic vault range (the difference in the central vault height from scotopic to photopic light condition) after implantation of the ICL/TICL (STAAR Surgical) and Eyecryl phakic/Eyecryl phakic toric intraocular lens (IOL) (Biotech Healthcare).

METHODS

This retrospective study included patients with myopia or myopic astigmatism eligible for phakic IOL implantation with either the ICL/TICL or Eyecryl phakic/Eyecryl phakic toric IOL. Vault changes in varying light conditions (scotopic, mesopic, and photopic) were assessed using an anterior segment optical coherence tomography-based tomographer and dynamic vault range (DVR) was compared between the two groups.

RESULTS

A total of 60 eyes from 36 patients (30 eyes in each group) with a mean age of 28.63 ± 6.36 years were included. The mean postoperative follow-up at the time of assessment was 9.4 ± 5.3 and 8.9 ± 5.28 months (P = .75) in the ICL and Eyecryl groups, respectively. The mean values of scotopic, mesopic, and photopic vault were 490.56 ± 238.64, 453.56 ± 224.30, and 373.96 ± 200.24 μm in the ICL group and 515.46 ± 174.34, 490.26 ± 184.04, 450.43 ± 173.92 μm in the Eyecryl group (P = .32, .24, and .05, respectively). The DVR was 116.6 ± 59.29 μm in the ICL group versus 65.03 ± 31.78 μm in the Eyecryl group (P < .001).

CONCLUSIONS

The Eyecryl phakic IOL showed significantly fewer light-induced changes in the central vault height (DVR) compared to the ICL, which may be attributed to the difference in the material of the two phakic IOL models. This may be clinically significant in eyes with low postoperative vaults with respect to their follow-up and risk assessment of cataractogenesis in the long term. [J Refract Surg. 2023;39(8):546-554.].

Diagnostic Techniques to Increase the Safety of Phakic Intraocular Lenses

Preoperative and postoperative diagnostics play an important role in ensuring the safety of patients with phakic intraocular lenses (pIOLs). The risk of endothelial cell loss can be addressed by regularly measuring the endothelial cell density using specular microscopy and considering the endothelial cell loss rate and the endothelial reserve in accordance with the patient's age when deciding whether to explant a pIOL. The anterior chamber morphometrics, including the anterior chamber depth and the distance between the pIOL and the endothelium, measured using Scheimpflug tomography and anterior segment optical coherence tomography (AS-OCT), can help to assess the risk of the endothelial cell loss. In patients undergoing posterior chamber pIOL implantation, accurate prediction of the vault and its postoperative measurements using AS-OCT or Scheimpflug tomography are important when assessing the risk of anterior subcapsular cataract and secondary glaucoma. Novel approaches based on ultrasound biomicroscopy and AS-OCT have been proposed to increase the vault prediction accuracy and to identify eyes in which prediction errors are more likely. Careful patient selection and regular postoperative follow-up visits can reduce the complication risk and enable early intervention if a complication occurs.

Binocular imbalance in patients after implantable collamer lens V4c implantation or femtosecond laser-assisted in situ keratomileusis for myopia with presbyopia

Aim

To investigate the long-term safety, efficacy, and binocular balance of monovision surgery using Implantable Collamer Lens (ICL) V4c implantation and Femtosecond Laser-Assisted in situ Keratomileusis (FS-LASIK) for the treatment of myopic patients with presbyopia.

Methods

This case series study involved 90 eyes of 45 patients (male/female = 19/26; average age:46.27 ± 5.54 years; average follow-up time:48.73 ± 14.65 months) who underwent the aforementioned surgery to treat myopic presbyopes. Data on manifest refraction, corrected distance visual acuity, dominant eye, presbyopic addition, intraocular pressure, and anterior segment biometric parameters were collected. The visual outcomes and binocular balance at 0.4 m, 0.8 m, and 5 m were documented.

Results

The safety index for the ICL V4c and FS-LASIK groups were 1.24 ± 0.27 and 1.04 ± 0.20 (p = 0.125), respectively. Binocular visual acuity (logmar) for 0.4 m, 0.8 m, and 5 m were -0.03 ± 0.05, -0.03 ± 0.02, and 0.10 ± 0.03 for the ICL V4c group, and -0.02 ± 0.09, -0.01 ± 0.02, and 0.06 ± 0.04 for the FS-LASIK group, respectively. The proportions of all patients with imbalanced vision at 0.4 m, 0.8 m, and 5 m distances were 68.89, 71.11, and 82.22%, respectively (all p > 0.05 between the two groups). There were significant differences in refraction between the balanced and imbalanced vision for patients at 0.4 m distance (for non-dominant eye spherical equivalent [SE]: -1.14 ± 0.17D and -1.47 ± 0.13D, p < 0.001), 0.8 m distance (for preoperative ADD:0.90 ± 0.17D and 1.05 ± 0.11D, p = 0.041), and 5 m distance (for non-dominant SE: -1.13 ± 0.33D and -1.42 ± 0.11D, p < 0.001).

Conclusion

ICL V4c implantation and FS-LASIK monovision treatment demonstrated good long-term safety and binocular visual acuity at various distances. After the procedure, the imbalanced patients' vision is primarily related to the age-related presbyopia and anisometropia progression caused by the monovision design.

Development and validation of a new multivariable prediction model to estimate risk of abnormal vault

PURPOSE

To develop and validate a new multivariable prediction model to estimate risk of abnormal vault after EVO Implantable Collamer Lens (EVO-ICL) implantation using the preoperative parameters.

METHODS

This retrospective study comprised 282 eyes of 143patients who underwent EVO-ICL surgery between May 2021 and April 2022. We measured preoperative parameters before surgery and vaults in 1 week after the operation using swept-source optical coherence tomography (SS-OCT). Risk factors for abnormal vault were determined by univariate and multivariate logistic regression analyses, and a nomogram was developed to forecast the risk of abnormal vault after EVO-ICL implantation. We assessed the performance of nomogram in terms of discrimination and calibration, including concordance index (C-index), receiver operating characteristic curve (ROC), area under the ROC curve (AUC), and decision curve analysis (DCA). Bootstrap resampling was used as an internal verification method.

RESULTS

The logistic regression analysis revealed the independent risk factors for abnormal vault were white-to-white(WTW), anterior chamber angle(ACA), pupil size, and ICL-size, all of them were used to establish a nomogram based on multivariate logistic regression to predict the risk of abnormal vault. The C-indexes and AUC were 0.669 (95%CI, 0.605, 0.733). The calibration curves of the nomogram showed relatively small bias from the reference line, implicating an acceptable degree of confidence. The DCA indicates the potential clinical significance of the nomogram.

CONCLUSIONS

We developed a new multivariable prediction model to estimate risk of abnormal vault. The model shows good prediction effect and can provide assistance for clinical decision of ICL size.

Long-Term Vault Changes in Different Levels and Factors Affecting Vault Change After Implantation of Implantable Collamer Lens with a Central Hole

INTRODUCTION

This study evaluated vault changes in eyes implanted with an implantable Collamer lens (ICL) with a central hole (ICL V4c) for myopia and astigmatism correction as well as factors related to vault changes over time.

METHODS

This retrospective study enrolled 169 myopic eyes from 169 patients (137 women and 32 men) who underwent ICL V4c implantation to correct myopia and astigmatism. Vault values were measured quantitatively using a rotating Scheimpflug camera. Each patient underwent at least four postoperative follow-up visits at 1 month, 6 months, 1 year, and more than 2 years. We compared postoperative values between groups and identified factors affecting vault changes over time.

RESULTS

The mean vaults at 1 month (baseline), 6 months, 1 year, and the last follow-up time following ICL implantation were 540.83 ± 186.13, 520.00 ± 196.08, 503.79 ± 198.30, and 471.42 ± 211.35 μm, respectively. Eyes with baseline vaults of 250-750 and ≥ 750 μm exhibited a trend of vault decrease over time, and the differences were statistically significant (P < 0.05) at 6 months and 1 year postoperatively, respectively. The variables relevant to the value of vault decrease between baseline and last follow-up time were anterior chamber depth (ACD) and ICL power (adjusted R² = 0.121, P < 0.001).

CONCLUSIONS

We found a trend of decreased mean objective vault values over time, which was more obvious in eyes with higher baseline vault values. The vault value of the ICL decreased more in eyes with shallower ACDs, higher ICL power, or both. Moreover, the decrease in vault values became statistically significant earlier in eyes with higher baseline vaults or shallower ACDs.

EVO/EVO+ Visian Implantable Collamer Lenses for the correction of myopia and myopia with astigmatism

INTRODUCTION

Intraocular lens implantation in phakic eyes for the correction of refractive error is currently a widespread procedure. The EVO and EVO+ Visian Implantable Collamer Lenses (ICL) are two of the most prevalent lenses implanted. They incorporate a central orifice to avoid the need for iridotomy. The main difference between both ICL is the higher optical diameter zone provided by the EVO+, allowing a better quality of vision at night. This review aims to provide an overview of the current ICL models available for correcting myopia and myopic astigmatism.

AREAS COVERED

During the last decade, more than 100 scientific papers analyzing the performance of EVO and EVO+ lenses have been published. This review describes the objective visual performance achieved with the implantation of central hole ICL lenses and the subjective perception of the patients implanted with these lenses. In addition, the safety and the potential complications associated with undergoing an EVO and EVO+ ICL implantation have been addressed.

EXPERT OPINION

Refractive surgeons and candidates to undergo ICL implantation should be aware of the excellent safety and visual outcomes provided by the implantation of central hole ICL lenses. However, future research could address minor issues currently not resolved.

Vault-Correlated Efficacy and Safety of Implantable Collamer Lens V4c Implantation for Myopia in Patients with Shallow Anterior Chamber Depth

INTRODUCTION

The aim of the study was to evaluate efficacy and safety outcomes after implantation of the Visian Implantable Collamer Lens (ICL V4c) in myopia patients with shallow anterior chamber depth (ACD).

METHODS

This retrospective study followed 163 eyes of 94 patients for at least 24 months. Uncorrected distance visual acuity (UDVA), corrected distance visual acuity, intraocular pressure (IOP), manifest refraction, vault, endothelial cell density (ECD), anterior chamber angle (ACA), anterior chamber volume, and the distance from the corneal endothelium to the central ICL (C-ICL) were measured during follow-ups. Spearman's correlation and logistic regression were used to identify variables correlated with changes in ECD and potential risk factors for ineffective outcomes, respectively.

RESULTS

All surgeries were performed safely. High IOP of 9 eyes and anterior capsular opacity of 5 eyes were observed. The last follow-up ACA had a significant difference between the high and normal IOP groups (p = 0.0003). The mean ECD and vault were 2,855.76 ± 270.82 cells/mm2 and 388.01 ± 135.28 μm at the last follow-up, respectively. The vault and C-ICL were significantly associated with ΔECD (all p < 0.05). Furthermore, the vault was most responsible for the ECD loss. Twenty-two eyes had unsatisfactory postoperative UDVA, and the low vault at the last follow-up was a significant risk factor for this ineffective outcome (p < 0.001, OR = 14.739).

CONCLUSIONS

ICL V4c implantation in patients with shallow ACD achieved stable visual outcomes. The vault is related to postoperative visual acuity and ECD loss, which needs to be paid attention during follow-up.

A quantitative study of the effect of ICL orientation selection on post-operative vault and model-assisted vault prediction

Background

Appropriate vault height of implantable collamer lens (ICL) implantation matters for it has risks of corneal endothelial cell loss, cataract formation and intraocular pressure elevation, which could lead to irreversible damage to optic nerve. Therefore, pre-operative prediction for an ideal vault height is a hotspot. However, few data exist regarding quantitative effect of ICL orientation on vault height. This study is aimed to quantitatively investigate the effect of ICL implantation orientation on vault height, and built a machine-learning (ML)-based vault prediction model taking implantation orientation into account.

Methods

473 consecutive case series treated with ICL implantation were retrospectively analyzed (408 were horizontally implanted, and 65 were vertically implanted). Multivariable logistic regression analysis was performed to determine the association between ICL orientation and achieved vault. ML was performed to develop a new vault height prediction model taking ICL orientation into account. Receiver operating characteristic curve (ROC) and net reclassification index (NRI) were obtained to assess the prediction ability.

Results

95% of all the patients achieved 20/20 uncorrected distance visual acuity (UDVA) or better. No complications including cataract formation, dispersion or optic nerve injury were observed in any cases. Sex, sphere power, cylinder power, axis, ICL size and ICL orientation were all significant risk factors associated to vault height, and age was positively co-related. Of note, ICL size and ICL orientation were the top-ranking risk factors. Comparing to conventional horizontal implantation, vertical implantation could reduce the achieved vault by 81.187 μm (p < 0.001). In regarding to different ICL sizes, vertical implantation had no good to vault reduction when using ICL of 12.1 mm. However, it could reduce the vault by 59.351 μm and 160.992 μm respectively when ICL of 12.6mm and 13.2 mm were implanted (p = 0.0097 and p = 0.0124). For prediction of vault height, ML based model significantly outperformed traditional multivariable regression model.

Conclusion

We provide quantitative evidence that vertical implantation of ICL could effectively reduce the achieved vault height, especially when large size ICL was implanted, comparing to traditional horizontal implantation. ML is extremely applicable in development of vault prediction model.

Intraocular Implantable Collamer Lens with a Central Hole Implantation: Safety, Efficacy, and Patient Outcomes

This review summarizes the available literature and provides updates on the efficacy, safety, and patient outcomes of phakic intraocular lens implantation using implantable collamer lens (ICL), with a focus on newer models with a central port (EVO/EVO+ Visian Implantable Collamer Lens, STAAR Surgical Inc.). All studies included in this review were identified from the PubMed database and were reviewed for relevancy of their topic. Data on hole-ICL implantation performed between October 2018 and October 2022 in 3399 eyes showed a weighted average efficacy index of 1.03 and a weighted average safety index of 1.19 within an average follow-up of 24.7 months. The incidence of complications such as elevated intraocular pressure, cataract, and corneal endothelial cell loss was low. Moreover, both quality of vision and quality of life improved after ICL implantation, confirming the benefits of this procedure. In conclusion, ICL implantation is a promising refractive surgery alternative to laser vision correction with excellent efficacy, safety, and patient outcomes.

Corneal diameter measurements by 3 optical biometers and their effect on phakic intraocular lens sizing

PURPOSE

To compare phakic intraocular lens size calculations based on corneal diameter (CD) measurements by 3 instruments.

SETTING

G.B. Bietti Foundation I.R.C.C.S., Rome, Italy.

DESIGN

Retrospective interventional case series.

METHODS

Preoperatively, CD was measured with the Aladdin, IOLMaster 700, and Pentacam AXL Wave. The simulated ICL size was computed by entering CD measurements into the manufacturer's calculator. Postoperatively, vaulting was measured by anterior segment optical coherence tomography. The optimal ICL size (OIS) was calculated and compared with the commercially available OIS (CAOIS).

RESULTS

54 eyes (29 patients) with the implantable collamer lens (ICL) were enrolled. The mean CD was 12.02 ± 0.36 mm with the Aladdin, 12.35 ± 0.39 mm with the IOLMaster 700, and 12.22 ± 0.41 mm with the Pentacam AXL Wave ( P &amp;lt; .0001), with the closest agreement between the Pentacam AXL Wave and IOLMaster 700 (95% limits of agreement: -0.43 to +0.17 mm). Vaulting (mean: 558 ± 261 μm) was within 251 and 1000 μm in 49 eyes (83.3%). The mean difference between the simulated ICL size and OIS ranged between -0.11 ± 0.35 mm and 0.10 ± 0.30 mm ( P &amp;lt; .0001), with no statistically significant difference between the IOLMaster 700 and Pentacam AXL Wave. The simulated ICL size was equal to CAOIS in 38 eyes (70.37%) with the Aladdin, 37 eyes (68.52%) with the IOLMaster 700, and 39 eyes (72.22%) with the Pentacam AXL Wave, without any statistically significant difference.

CONCLUSIONS

CD measurements by the 3 devices lead to similar percentages of eyes with an ICL size equal to the OIS. Agreement is closer between the IOLMaster 700 and Pentacam AXL Wave.

Analysis of perioperative problems related to intraocular Implantable Collamer Lens (ICL) implantation

PURPOSE

To introduce a modified procedure of ICL implantation, to summarize the perioperative problems and their corresponding treatment after myopia correction with Implantable Collamer Lens (ICL), and to compare the difference of complications between the no-hole ICL and hole ICL.

METHODS

We searched all articles on ICL-related perioperative problems and their corresponding treatment in Scopus, Embase, PubMed and Web of Science databases for the last 22 years.

RESULTS

ICL implantation is safe, effective, stable and predictable in the correction of myopia, hyperopia and astigmatism, but can also cause a series of perioperative problems, including intraoperative and postoperative complications.

CONCLUSION

There are many kinds of complications related to ICL, but the common intraoperative and postoperative complications mainly include abnormality of arch height, abnormal position of ICL, loss of corneal endothelial cells and corneal decompensation, high intraocular pressure and secondary glaucoma, cataract and night vision symptoms. Compared with ICL without central pore, the incidence of complications such as loss of corneal endothelial cells and corneal decompensation, high intraocular pressure and secondary glaucoma and cataract was relatively lower in central hole ICL, while postoperative complications such as night vision symptoms were obvious.

Efficacy and safety after posterior chamber Implantable Collamer Lens implantation according to preoperative anterior chamber depth: Short-term comparative study

PURPOSE

To compare visual, refractive, and safety outcomes of posterior chamber Implantable Collamer Lens (ICL) implantation for the correction of myopia according to the preoperative anterior chamber depth (ACD).

METHODS

Retrospective, comparative study, patients submitted to implantation of myopic posterior-chamber phakic Implantable Collamer Lens (ICL), model V4C/V5, minimum follow-up of 12 months; two groups were created: Group 1 (ACD 2.80 to 2.99 mm) and Group 2 (ACD equal to or greater than 3.00 mm). The parameters evaluated were uncorrected and corrected visual acuity, subjective refraction, efficacy and safety index, predictability, endothelial cell density, central vault, anterior chamber angle and postoperative complications. A total of 558 eyes from 298 patients were evaluated: 111 eyes (19.9%) in group 1 and 447 eyes (80.1%) in group 2.

RESULTS

At 12 months, the efficacy index was similar in both groups (p = 0.264); the safety index was higher in group 1 (p = 0.031); the mean central Vault was significantly lower in group 1 (212.8 vs 410.6 μm; p < 0.001). Respectively, 93 (83.8%) and 366 (84.1%) eyes were within ±0.50 D of targeted refraction. Anterior chamber angle significantly decreased during follow-up in both groups (p < 0.001; p < 0.001). Intraocular pressure did not change significantly (p = 0.310 and p = 0.446, respectively). There were no significant differences in endothelial cell density loss (p = 0.278) or in the rate of complications observed (p = 0.733).

CONCLUSIONS

ICL implantation is an effective and safe procedure in eyes with shallow anterior chambers, with visual and refractive results and complication rates identical to those obtained in deeper anterior chambers.

Comparison of white-to-white measurements using four devices and their determination of ICL sizing

BACKGROUND

To compare the measurements obtained from the Orbscan II, IOLMaster 700, Pentacam AXL, and Castroviejo caliper and their effects on calculating the recommended implantable collamer lens (ICL) size and postoperative vault measurements.

METHODS

This is a retrospective cross-sectional study of patients who underwent ICL surgery by a single surgeon from March 1, 2018 to July 31, 2021. Records were reviewed for the anterior chamber depth (ACD) and white-to-white (WTW) measurements obtained from the Orbscan II, IOLMaster 700, Pentacam AXL, and Castroviejo caliper (WTW only). These were used to calculate the recommended ICL size. The actual ICL size implanted, and vault measurements obtained one month postoperatively were also collected.

RESULTS

One hundred seven eyes with a mean age of 27.9 ± 7.7 years were included in the study. Mean WTW measurements were significantly different between devices (P < 0.0001), with the IOLMaster 700 having the highest value (12.14 ± 0.04 mm) and the caliper having the lowest value (11.45 ± 0.04 mm). Mean ACD measurements were the lowest in Orbscan II (3.12 ± 0.25 mm) and the highest in Pentacam AXL (3.16 ± 0.24 mm). The Pentacam AXL produced an ICL size similar to the Orbscan in 69.2% of eyes. The IOLMaster yielded an ICL measurement one size larger than Orbscan-based calculations in 64.5% of eyes. Using the Orbscan WTW and ACD, the desired vault of 0.25 to 0.75 mm and 0.25 to 1.00 mm was achieved in 70% and 91% of eyes, respectively. Substituting caliper WTW to IOLMaster 700 or Pentacam AXL WTW increases the percentage of achieving the desired vault to 80%, similar to the Orbscan.

CONCLUSIONS

The Orbscan II, IOLMaster 700, and Pentacam AXL cannot be used interchangeably for calculating ICL sizing. Combining the WTW from caliper measurement with the ACD of the IOLMaster 700 or Pentacam AXL could improve ICL sizing and achieve a higher percentage of eyes with the desired vault.

Factors leading to realignment or exchange after implantable collamer lens implantation in 10 258 eyes

PURPOSE

To evaluate the incidence, causes, and outcomes of implantable collamer lens (ICL) realignment or exchange after implantation of the EVO-ICL.

SETTING

Eye and ENT Hospital of Fudan University, China.

DESIGN

Retrospective study.

METHODS

The study included 10 258 consecutive eyes after ICL implantation. Preoperative refractive and biometric measurements were compared between eyes with and without realignment or exchange. For eyes with ICL realignment or exchange, visual and biometric outcomes were also compared before and after ICL realignment or exchange.

RESULTS

The overall incidence of ICL realignment or exchange was 0.21% 22 eyes. 12 eyes (0.12%) underwent ICL realignment by axis rotation (10 eyes) or ICL exchange (2 eyes) due to toric ICL (TICL) misalignment. After realignment, uncorrected distance visual acuity improved, and residual cylinder decreased from -1.75 ± 0.48 diopters (D) to -0.87 ± 0.59 D ( P = .01). 10 eyes (0.10%) underwent vertical rotation of ICL (3 eyes) or ICL exchange (7 eyes) due to excessive vault. After either vertical rotation or ICL exchange, vault decreased significantly ( P < .05).

CONCLUSIONS

The incidence of ICL realignment or exchange after ICL implantation is low. TICL misalignment and excessive vault are 2 main causes. Implant exchange may be performed for excessive vault or misalignment with an insufficient vault. In addition, vertical rotation of an ICL may be a less invasive method to treat excessive vault in certain cases.

Three-year follow-up of posterior chamber phakic intraocular lens with a central port design after deep anterior lamellar keratoplasty

Background

To evaluate clinical outcomes of the Visian implantable collamer lens (ICL) with a central port to correct myopia and astigmatism after deep anterior lamellar keratoplasty (DALK) for keratoconus throughout 3 years of follow-up.

Methods

This study included 20 eyes of 20 patients that underwent V4c ICL (13 eyes with a spherical ICL and 7 eyes with a toric ICL) implantation after DALK. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, intraocular pressure (IOP), endothelial cell density (ECD), and vault were analyzed.

Results

The mean UDVA improved from the preoperative 1.18 ± 0.33 logMAR to 0.25 ± 0.14 logMAR at 6 months after surgery (P < 0.0001) and remained unchanged throughout the whole follow-up (P = 0.4). All eyes gained lines of CDVA compared to preoperative values. At the last follow-up visit, all eyes achieved CDVA of 0.2 logMAR or better and 13 eyes (65%) 0.1 logMAR or better. At 6 months post-surgery, all eyes (100%) had a spherical equivalent within ± 1.50 D, and 19 (95%) within ± 1.00 D. The mean manifest spherical equivalent was stable over the postoperative follow-up (P = 0.25). No significant increase in IOP occurred in any case throughout the 3 years of follow-up. The loss in ECD from the preoperative baseline at the last follow-up visit was 2.27%.

Conclusions

The clinical outcomes suggest that the V4c ICL implantation for correction of myopia and regular astigmatism in post-DALK eyes was satisfactory in terms of effectiveness, safety, and stability during 3 years of follow-up.

Implantable collamer lens sizing based on measurement of the sulcus-to-sulcus distance in ultrasound biomicroscopy video clips and ZZ ICL formula

BACKGROUND

To evaluate a new method of implantable collamer lens (ICL) sizing based on ultrasound biomicroscopy (UBM) video clips.

METHODS

This observational study included consecutive patients with myopia and myopic astigmatism scheduled for V4c toric ICL (TICL) implantation (STAAR) at Hangzhou MSK Eye Hospital (October 2020 to November 2020). Sulcus-to-sulcus (STS) distance, lens thickness (LT), and clinical refraction were measured preoperatively. The ZZ ICL formula (provides the predicted vault height and refraction based on TICL size, intraocular meridian, power, and eye parameters, including STS distance and LT) was used to select TICL size and predict vault height and residual refraction, which was also compared with the STAAR software recommended. Vault and residual refraction were measured at 3 months postoperatively.

RESULTS

The analysis included 168 eyes in 84 patients. Postoperative vault size was comparable to that predicted by the ZZ ICL formula (528 ± 193 vs. 545 ± 156 μm, P = 0.227). Vault prediction error (PE) by the ZZ ICL formula was within 100, 300, and 500 μm in 40.48%, 88.10%, and 100% of eyes, respectively. Spherical equivalent (SE) and absolute cylindrical refractive error were 0.36 ± 0.48 and 0.40 ± 0.31 D at 3 months postoperatively. The SE PE, absolute cylindrical PE, and percentages of eyes with an absolute cylindrical PE within ± 0.50 D and ± 1.00 D were lower for the ZZ ICL formula than for the STAAR software (P < 0.01).

CONCLUSIONS

Combining measurements obtained in UBM video clips with the ZZ ICL formula provides an effective method of sizing TICLs and predicting vault height and residual refractive error.

U.S. military implantable collamer lens surgical outcomes: 11-year retrospective review

PURPOSE

To examine the long-term efficacy and safety of myopic implantable collamer lens (ICL) implantation in active duty personnel of U.S. military.

SETTING

Hospital practice.

DESIGN

Retrospective longitudinal observational study.

METHODS

1485 patients (median age 25, interquartile range 22 to 29) underwent ICL surgery. Patients received a preoperative examination including uncorrected distance visual acuity (UDVA), intraocular pressure (IOP), manifest refraction measuring corrected distance visual acuity (CDVA), corneal topography and tomography, qualitative grading of perceived ectatic risk, ophthalmic biometry, and baseline endothelial cell counts (ECCs). Outcome measures included UDVA, IOP, vault size, manifest refraction, CDVA, and ECCs. The long-term follow-up data ware drawn from the U.S. military medical record system.

RESULTS

A total of 3105 eyes were evaluated. Patients received ICLs because of either abnormal topography (2111 eyes [68%]) or high myopia (994 eyes [32%]). 94 eyes (80%) maintained UDVA of 20/25 or better up to 8 years postoperatively. The rate of achieving the desired refractive correction was 97% (503 eyes) at 1 year and 90% (81 eyes) at 8 years. Stability of these outcomes was also shown by minimal change in manifest refraction. Documented mean ECC loss was 22% at postoperative year 5. The overall rate of adverse events was 1.2% (36 eyes) including visually significant cataract formation, glaucoma, retinal detachment, and traumatic incision opening. A removal or replacement rate of 4.5% (135 eyes) was observed.

CONCLUSIONS

ICL implantation was found to be effective and safe. Vault sizes decreased over time, suggesting an increased risk of cataract formation after 7 years. Further study is necessary to assess long-term clinical significance of ECC decline.

Evaluation of impact of posterior phakic IOL implantation on biometry and effectiveness of concomitant use of anterior segment OCT on IOL power calculation for cataract surgery

PURPOSE

To evaluate the effects of phakic intraocular lens (pIOL) implantation on the intraocular lens (IOL) power calculation and subsequently to evaluate the effectiveness of concomitant use of anterior segment optical coherence tomography (AS-OCT) against biometric changes.

SETTING

Masayuki Ouchi Eye Clinic, Kyoto, Japan.

DESIGN

Prospective consecutive case series.

METHODS

100 patients (100 eyes) who underwent pIOL implantation were enrolled. In each eye, biometry was performed using partial coherence interferometry (PCI) and AS-OCT. Pre-pIOL and post-pIOL implantation IOL power calculation using SRK/T (S), Haigis (H), and Barret Universal II (B) formulas was compared.

RESULTS

100 patients (100 eyes) were included. Anterior chamber depth (ACD) was significantly shorter at post-pIOL implantation for both PCI (P < .001) and AS-OCT (P = .05). When using PCI, the crystalline lens surface was misidentified in 75% of eyes, and in these eyes, the ACD difference between pre-pIOL and post-pIOL implantation exceeded that with both PCI and AS-OCT. The estimated IOL power was significantly lower at post-pIOL implantation according to the H and B formulas (both P < .001) but remained unchanged by the S formula. However, no difference was observed when AS-OCT-derived ACD and lens thickness (LT) values were introduced in the H (P = .16) and B (P = .55) formulas.

CONCLUSIONS

Misidentification of the lens surface occurs in many pIOL-implanted eyes with PCI measurements and could influence the power calculation with H and B formulas while leaving the S formula unaffected. AS-OCT-derived ACD and LT value substitution is recommended for H and B formulas.

Outcomes of the EVO ICL Using a Customized Non-horizontal or Horizontal Implanting Orientation Based on UBM Measurement: A Pilot Study

Introduction

To evaluate the short-term safety and efficacy of the EVO implantable collamer lens (ICL) using a customized implanting orientation design based on ultrasound biomicroscope (UBM) measurement.

Methods

The prospective case series included 310 eyes of 158 patients treated with ICL. To achieve an optimal vault, an ICL of specific size was chosen and implanted in a customized orientation according to assessment of sulcus-to-sulcus (STS) diameters, distance between STS plane and crystalline lens (STSL), the morphology of ciliary sulcus (MCS), anterior chamber depth (ACD), and white-to-white (WTW). With the new design, there were 138 eyes with a non-horizontal orientation and 172 eyes with a horizontal orientation of the ICL. Refractive and ICL vault statuses were followed up for 1 day and 1 month postoperatively.

Results

The safety index at 1 month was 1.34 ± 0.17 for the non-horizontally implanted group and 1.33 ± 0.16 for the horizontally implanted group; the efficacy index was 1.21 ± 0.18 for the non-horizontally implanted group and 1.18 ± 0.16 for the horizontally implanted group. All eyes achieved an uncorrected distance visual acuity of 0.10 logMAR or better. No significant difference in endothelial cell density was observed between the preoperative value (2792.6 ± 247.6 cells/mm²) and value at 1 month postoperatively (2744.2 ± 243.3 cells/mm²), and no cataract or anterior subcapsular opacification was observed. Ideal vault (250–750 μm) was achieved in 84% of eyes (260/310).

Conclusion

The customized ICL design of implanting orientation based on UBM measurement provides good safety, efficacy, and vault predictability.

Supplementary Information

The online version contains supplementary material available at 10.1007/s40123-022-00498-8.

Agreement of implantable collamer lens sizes using parameters from different devices

Objective

To assess agreement and repeatability of white-to-white (WTW) and anterior chamber depth (ACD), and agreement of implantable collamer lens (ICL) size using these measurements from different devices.

Methods and analysis

A retrospective review of 83 eyes with ICL implantation (42 patients) was conducted. The agreement of WTW (measured with WaveLight Topolyzer and Orbscan IIz) and ACD (measured with WaveLight Oculyzer and Orbscan IIz) was analysed. Correlation of ICL sizes and difference of eyes with unacceptable vaults between two data sets (WaveLight platform; Topolyzer and Oculyzer and Orbscan IIz) were assessed.

Results

Average WTW measured by Orbscan IIz and Topolyzer demonstrated good agreement (Ρ 0.884) with low systematic bias (−0.03±0.1 mm) and narrow 95% limits of agreement (LoA) of −0.28 to 0.22. Average ACD measured by Orbscan IIz and Oculyzer also showed good agreement (Ρ 0.903) with low systematic bias (−0.04±0.1 mm) and relatively narrow 95% LoA (0.2 to 0.12). ICL size selected according to two data sets showed moderate to strong level of agreement (Kappa=0.81). There was a statistically significant difference (p<0.001) in the proportion of eyes with unacceptable postoperative vaults when using the Wavelight platform data set (five eyes, 6.02%) and the Orbscan IIz data set (12 eyes, 14.46%).

Conclusion

Although the agreement of WTW and ACD between devices was good, there was a significant difference in proportion of eyes with unacceptable postoperative vaults when using two data sets. Therefore, Topolyzer and Oculyzer might not be suitable for operating interchangeably with Orbscan IIz for ICL size selection.

EVO+ Implantable Collamer Lens KS-aquaPORT Location, Stability, and Impact on Quality of Vision and Life

PURPOSE

To determine the longitudinal variation in the KS-aquaPORT central hole location of the phakic EVO+I Implantable Collamer Lens (ICL) (STAAR Surgical) and analyze its influence on visual performance, quality of vision (QoV), and quality of life (QoL).

METHODS

A prospective study was performed including 36 patients who had EVO+ ICL implantation. The KS-aquaPORT central hole location (Cartesian and polar coordinates) was determined with respect to the pupil center and visual axis. The effect of time (6-month follow-up) on central hole location was analyzed using linear mixed models. The effect of the KS-aquaPORT location on visual performance, QoV, and QoL parameters was assessed with multivariate regression models.

RESULTS

With respect to the visual axis, no significant changes in KS-aquaPORT location were found during follow-up. With respect to the pupil center, the X-coordinate and radius of KS-aquaPORT location showed modest, but significant (P ≤ .05) differences between 1-week and 3-month postoperative visits, and between 1-week and 6-month visits. X-coordinate variation was significant (P = .022) between 1-and 6-month visits. With respect to the visual axis, greater KS-aquaPORT decentration was associated with worse visual acuity (X-coordinate: P = .004; radius: P = .006), and inferior decentration with longer xenon-type glare photostress recovery time (P = .021). With respect to the pupil center, a lower radius was associated with better QoV scores (P ≤ .01) and temporal decentration produced higher ring-shaped dysphotopsia (P = .007).

CONCLUSIONS

EVO+ ICL KS-aquaPORT location appears to be clinically stable up to 6 months postoperatively. A central location of the EVO+ ICL KS-aquaPORT hole is preferred because it allows reduced perception of dysphotopic phenomena that can result in better QoV. [J Refract Surg. 2022;38(3):177-183.].

Long-term follow-up for monovision surgery by Implantable Collamer Lens V4c implantation for myopia correction in early presbyopia

Purpose

To investigate the long-term safety and efficacy of monovision surgery using implantable collamer lens V4c (ICL V4c) implantation in myopic patients with early presbyopia.

Setting

Eye and ENT Hospital of Fudan University, Shanghai, China.

Design

Prospective case series study.

Methods

This study included 64 eyes of 32 patients with early presbyopia, who underwent bilateral ICL V4c implantation for myopia correction. Parameters, including mean spherical equivalent (SE), uncorrected distance visual acuity, corrected distance visual acuity, intraocular pressure, endothelial cell density, presbyopic add power, visual acuity (logMAR) of dominant eyes (D-eye), nondominant (nD-eye) eyes, and both eyes (Bi) at 0.4 m, 0.8 m, and 5 m were recorded at the last follow-up.

Results

All surgeries were uneventful. At the last follow-up, the safety indices were 1.23 ± 0.18 (D-eyes) and 1.21 ± 0.18 (nD-eyes) (p > 0.05); the efficacy indices were 0.95 ± 0.27 (D-eyes) and 0.92 ± 0.28 (nD-eyes) (p < 0.05), the SE was -0.62 ± 0.47 D (D-eyes); and − 1.21 ± 0.78D (nD-eyes) (p < 0.05), presbyopic add power was 1.31 ± 0.58 D. The visual acuity (logMAR) of D-eyes, nD-eyes, and binocular (Bi) at 5.0 m were: 0.06 ± 0.15 (D-eye), 0.21 ± 0.18 (nD-eye), (p < 0.01), and 0.04 ± 0.13 (Bi); 0.8 m: 0.03 ± 0.18 (D-eye), 0.08 ± 0.16 (nD-eye), (p > 0.05), and − 0.02 ± 0.11 (Bi); 0.4 m: 0.08 ± 0.09 (D-eye), − 0.02 ± 0.08 (nD-eye), (p < 0.001), and − 0.03 ± 0.09 (Bi). Subjects were very satisfied or felt excellent with their visual acuity at near (81.25%) and far distances (87.50%), respectively (versus preoperative, p < 0.001).

Conclusion

Monovision surgery using ICL V4c implantation is safe and practicable for correction of myopes with presbyopia, with long-term efficacy at near and far distances and patient satisfaction.

Changes of ocular biometry in eyes with posterior chamber phakic intraocular lens implantation

OBJECTIVE

To evaluate changes in biometric variables and intraocular lens (IOL) calculation results after posterior chamber phakic IOL (PCPIOL) implantation.

METHODS

This retrospective, observational study included 65 eyes of 38 patients who underwent PCPIOL (EVO Visian ICL) implantation for correction of myopia. Prior to and a minimum of one year (mean 14.9 months) after EVO Visian ICL implantation, biometric variables and IOL calculation results were compared. Optical biometry, including anterior chamber depth, axial length, flat, steep, and mean keratometry values and IOL calculation results for the Holladay 2, Hoffer Q, Haigis, and SRK/T formulas were measured using the IOLMaster 700 SWEPT Source OCT biometer.

MAIN RESULTS

The mean anterior chamber depth decreased from 3.70±0.22mm to 3.34±0.39mm, the mean axial length increased from 26.61±1.61mm to 26.71±1.66mm, and the mean flat keratometry changed from 42.82±1.86 D to 42.73±1.83 D. These changes were statistically significant. The mean IOL power calculation also revealed a statistically significant decrease with all four formulas (ranging from 0.19 D to 0.30 D) after PCPIOL implantation.

CONCLUSIONS

Biometric variables and IOL calculation results showed statistically significant changes one year after EVO Visian ICL implantations. However, IOL power calculations yielded a decrease of less than 0.50 D, inducing much less refractive deviation in the spectacle plane; and the change was primarily related to an increase in AL measurements. IOL power calculations in eyes with EVO Visian ICL in situ provided satisfactory and reliable results.

Correlation between intraoperative and postoperative vaulting of the EVO implantable Collamer lens: a retrospective study of real-time observations of vaulting using the RESCAN 700 system

Background

Implantable Collamer lens (ICL) vaulting is one of the most important parameters for the safety, aqueous humor circulation, and lens transparency after ICL implantation. This study aimed to investigate the factors associated with the actual vaulting after refractive EVO-ICL surgery.

Methods

This retrospective study included patients who underwent EVO-ICL surgery at a tertiary eye hospital between October and December 2019. A RESCAN 700 was used for the intraoperative and CIRRUS HD-OCT was used for postoperative observation of vaulting. Subjective and objective refractions, anterior ocular segment, corneal morphology, intraocular pressure (IOP), anterior chamber volume (ACV), crystalline lens rise (CLR), white-to-white distance (WTW), anterior chamber depth (ACD), axial length, corneal endothelial cell density (ECD), and fundoscopy were examined. A multivariable analysis was performed to determine the factors independently associated with 1-month postoperative vaulting.

Results

Fifty-one patients (102 eyes) were included. Compared with the eyes with normal vaulting, those with high vaulting had higher preoperative diopter values (P = 0.039), lower preoperative corrected visual acuity (P = 0.006), lower preoperative IOP (P = 0.029), higher preoperative ACD (P = 0.004), lower preoperative CLR (P = 0.046), higher ICL spherical equivalent (P = 0.030), higher intraoperative vaulting (P < 0.001), and lower IOP at 1 month (P = 0.045). The multivariable analysis showed that the only factor independently associated with high vaulting at 1 month after surgery was the intraoperative vaulting value (odds ratio = 1.005, 95% confidence interval: 1.002–1.007, P < 0.001). The intraoperative and 1-month postoperative vaulting values were positively correlated (R² = 0.562).

Conclusions

The RESCAN700 system can be used to perform intraoperative optical coherence tomography to predict the vaulting value of ICL at 1 month.

Distribution of White-to-White Corneal Diameter and Anterior Chamber Depth in Chinese Myopic Patients

Purpose: To investigate the distribution of white-to-white (WTW) corneal diameter and anterior chamber depth (ACD) in Chinese myopia patients. Methods: This was a cross-sectional observational study conducted at five ophthalmic centers. Anterior segment biometry was performed in 7,893 eyes of the 7,893 myopic patients using Pentacam, and the WTW and ACD were recorded. The distribution patterns of WTW and ACD were evaluated and the correlation between WTW and ACD was analyzed statistically. Results: There were 4416 (55.95%) males and 3477 (44.05%) females. The age of the study population was 25.14 ± 5.41 years. Distribution of WTW was slightly positively skewed (Skewness = 0.0076, Kurtosis = 0.3944, KS P = 0.020) with a mean of 11.65 ± 0.38 mm and a 95% normal range of 10.91-12.39 mm. A significant difference in WTW was found among different myopia groups (P < 0.001). The ACD was normally distributed (Skewness = 0.899, Kurtosis = 0.027, KS P = 0.086). The mean ACD was 3.25 ± 0.26 mm and the 95% normal range of was 2.74-3.75 mm. A significant difference in ACD was also found among different myopia groups (P = 0.030). There was a significant correlation between WTW and ACD (r = 0.460, P < 0.001). Conclusions: In our study, 95% of the Chinese myopic patients had a WTW within 10.91-12.39 mm and an ACD within 2.74-3.75 mm. ACD and WTW were significantly different among different myopia, gender and age groups. WTW was positively correlated with ACD.

Bilateral Cataract Development and Pupillary Block Glaucoma Following Implantable Collamer Lens

Aim and objective

We report the first case of bilateral cataract formation and pupillary block glaucoma and high intraocular pressure (IOP) following implantable Collamer lens (ICL) implantation that resulted in advanced visual field loss.

Background

The patient who underwent bilateral ICL implantation can develop bilaterally elevated IOP and an anterior subcapsular cataract with altitudinal visual field defect.

Case description

A 38-year-old man with high myopia presented for routine follow-up status post bilateral phakic ICL placement. The visual acuity was reduced due to an anterior subcapsular cataract and elevated IOP in both eyes with advanced glaucomatous visual field defects. The patient was treated with topical glaucoma medications. The left eye underwent same-day phakic ICL explanation and cataract surgery to prevent further visual field loss.

Conclusion

Cataract and glaucoma are serious complications after phakic ICL implantation; therefore, regular postoperative monitoring may prevent advanced visual impairment.

Clinical significance

The use of a phakic intraocular lens for the correction of myopia may result in complications. As a measure is to reduce such complications, refractive surgeons preferred using phakic posterior chamber intraocular Collamer lens for the correction of myopia.

How to cite this article

Owaidhah O, Al-Ghadeer H. Bilateral Cataract Development and Pupillary Block Glaucoma Following Implantable Collamer Lens. J Curr Glaucoma Pract 2021;15(2):91–95.

Inter-device measurement variability of vital data parameters for keratorefractive and cataract refractive surgery

Introduction:

The measurements of corneal white-to-white (WTW) diameter and pupil size are critical for decision making in refractive surgery. Currently, automatic measurement of keratometry, corneal WTW, and pupil size are implemented in several ocular devices. The purpose of this study was to examine the agreement between two commonly used devices, an autorefractor and an optical biometer, for these parameters.

Methods:

Measurements were performed with both a Lenstar LS-900 and Nidek ARK-1 by an experienced examiner in random order. The devices were placed in close proximity within the same dimly lit room.

Results:

The measurements of 65 right eyes were analyzed. The results of the flat, steep, and mean keratometric reading were not significantly different (p = 0.96, p = 0.90, p = 0.93, respectively). Corneal WTW distances showed only moderate agreement between devices and were found to be significantly different (r = 0.8071; p < 0.01). Pupil diameters showed poor agreement between devices and were significantly different (r = 0.4890; p < 0.01). Agreement between implantable contact lens sizing, based on the measurements obtained by the two devices, was achieved for 19 of the 51 eyes (37.3%).

Conclusion:

We found a significant difference in WTW and pupil size measurements between ARK-1 and Lenstar. Results for both of the devices cannot be considered interchangeable for these data parameters.

Prediction of the trabecular iris angle after posterior chamber phakic intraocular lens implantation

PURPOSE

To create an equation for predicting the trabecular iris angle (TIA) and to verify its accuracy after implantable collamer lens (ICL) implantation.

SETTING

Nagoya Eye Clinic, Nagoya, Japan.

DESIGN

Retrospective evaluation of a screening approach.

METHODS

The subjects included 174 eyes (174 patients) that underwent ICL implantation. Patients were randomly assigned to the prediction equation group (116 eyes) or verification group (58 eyes). Anterior segment optical coherence tomography (AS-OCT; CASIA2 TOMEY) was performed before and 3 months after ICL surgery. For the prediction group, a prediction equation was created with the preoperative AS-OCT parameters and ICL size as independent variables and the postoperative anterior chamber depth (ACD) as dependent variables. Then, by applying the predicted post-ACD and preoperative AS-OCT parameters as independent variables and TIA after ICL surgery as the dependent variable, a prediction equation was created to predict the postoperative TIA (post-TIA) after ICL surgery. Each prediction equation was created using stepwise multiple regression analysis, and its accuracy was verified by a Bland-Altman plot in the verification group.

RESULTS

The explanatory variables (standardized partial regression coefficient) selected in the post-TIA prediction equation were post-ACD (0.629), TIA750 (0.563), iris curvature (0.353), pupil diameter (-0.281), iris area (-0.249), and trabecular iris space area 250 (-0.171) (R2 = 0.646). There were no clinically significant systematic errors between measured and predictive post-TIA values in the verification group. The average absolute prediction error was 3.43° ± 2.22°.

CONCLUSIONS

Post-TIA can be accurately predicted from the predicted post-ACD and other preoperative AS-OCT parameters.

Effect of pupil size on posterior chamber phakic intraocular lens vault measurements

Purpose

The aim of this study was to measure the implantable collamer lens (ICL) vault changes with anterior segment optical coherence tomography (AS-OCT) after the implantation of the Visian posterior chamber phakic ICL with a central hole (V4c) in relation to the pupil size.

Methods

This retrospective observational pilot study included 32 eyes of 16 patients, who underwent V4c ICL implantation. ICL vault was measured with AS-OCT in undilated and fully dilate state of the pupil. Primary outcome measure was the change in the vault of V4c ICL at the maximum and minimum pupil size.

Results

Median (IQR) undilated and post-dilated vault measurement was 393.00 (335.50-493.50) microns and 421.00 (338.50-503.75) microns, respectively, which was not statistically significant (P = 0.44).

Conclusion

No statistically significant difference was observed between the undilated and post-dilated ICL vault measurements. Hence, the postoperative vault can be measured either in resting, undilated state or fully dilated state of the pupil and would be similar irrespective of the pupil size.

Current Developments in Corneal Topography and Tomography

Introduction: Accurate assessment of the corneal shape is important in cataract and refractive surgery, both in screening of candidates as well as for analyzing postoperative outcomes. Although corneal topography and tomography are widely used, it is common that these technologies are confused. The aim of this study was to present the current developments of these technologies and particularly distinguish between corneal topography and tomography. Methods: The PubMed, Web of Science and Embase databases were the main resources used to investigate the medical literature. The following keywords were used in various combinations: cornea, corneal, topography, tomography, Scheimpflug, Pentacam, optical coherence tomography. Results: Topography is the study of the shape of the corneal surface, while tomography allows a three-dimensional section of the cornea to be presented. Corneal topographers can be divided into large- and small-cone Placido-based devices, as well as devices with color-LEDs. For corneal tomography, scanning slit or Scheimpflug imaging and optical coherence tomography may be employed. In several devices, corneal topography and tomography have been successfully combined with tear-film analysis, aberrometry, optical biometry and anterior/posterior segment optical coherence tomography. Conclusion: There is a wide variety of imaging techniques to obtain corneal power maps. As different technologies are used, it is imperative that doctors involved in corneal surgery understand the science and clinical application of devices for corneal evaluation in depth.

Changes in ocular parameters the crystalline lens after implantation of a collamer lens

CLINICAL RELEVANCE

Understanding changes in ocular anatomical parameters after intraocular lens implantation will allow a more accurate determination of dioptric power prior to surgery.

BACKGROUND

The crystalline lens position might change due to the implantation and removal of an implantable collamer lens (ICL) or toric implantable collamer lens (TICL). This study aimed to assess the effect of ICL implantation on position of the crystalline lens.

METHODS

This retrospective study was conducted on patients who underwent V4c ICL or V4c TICL implantation between March and September, 2018. Preoperative and post-operative (2 weeks, 3 months and 6 months) axial length, central corneal thickness, crystalline lens position, crystalline lens thickness and vault height were analysed. Multivariable linear regression was used to determine the variables associated with 6-month changes in lens position.

RESULTS

This study included 117 eyes of 117 patients. There were decreases in all vertical distance measures from the central corneal endothelium to the anterior and posterior crystalline lens capsule (all p > 0.05). The amount of reduction was related to the crystalline lens position before the operation and crystalline lens thickness after the operation (all p < 0.01). An error in anterior chamber depth and lens thickness may appear when the ICL/TICL is close to the crystalline lens.

CONCLUSION

Phakic intraocular lens implantation resulted in lens thickening and forward movement on day 1 post-operatively, which becomes stable within 6 months. Preoperative lens position and post-operative lens thickness were related to the amount of movement.

Clinical results of Visian implantable collamer lens implantation according to various sizes and implantation angles

PURPOSE

To investigate the clinical outcomes of Visian implantable collamer lens (ICL) implantation according to lens size and implantation angle.

SETTING

Onnuri Smile Eye Clinic, Seoul, Republic of Korea.

DESIGN

Retrospective case series.

METHODS

This study included 566 eyes of 283 patients treated with ICL implantation. Patients were divided into three groups: horizontally implanted same-sized ICL (group A), horizontally implanted different sized-ICL (group B: large ICL and small ICL) and same sized-ICL implanted with a different implantation angle (group C: horizontal and vertical).

RESULTS

At 12-month follow-up, the mean vault was 0.78 ± 17, 0.48 ± 0.13, 0.71 ± 0.18 and 0.44 ± 0.16 mm when large and small sized ICL was used in group B (p < 0.001), and when ICL was horizontally and vertically implanted in group C (p = 0.021), respectively. And the mean SE was -0.11 ± 0.30, -0.34 ± 0.42, -0.3 ± 0.56 and -0.64 ± 0.66 dioptres (D), when the large and the small sized ICL was used group B (p = 0.039), and when the ICL was horizontally and vertically implanted in group C (p = 0.036), respectively. No significant difference in UDVA, IOP and ECD between both eyes in groups B and C was observed. No statistical difference was found in the vault between both eyes for groups B and C.

CONCLUSIONS

The vault was significantly higher and the SE was significantly more hyperopic when a larger-sized ICL was used or the ICL was horizontally implanted compared to when the ICL was vertically implanted.

Long-term assessment of crystalline lens transparency in eyes implanted with a central-hole phakic collamer lens developing low postoperative vault

PURPOSE

To assess long-term crystalline lens transparency in eyes implanted with phakic collamer intraocular lens (pIOL) with a central port and low postoperative vault for correction of myopia.

SETTING

Clinica Baviera, Madrid, Spain.

DESIGN

Retrospective cross-sectional single-center study.

METHODS

Using a noninvasive Fourier-domain swept-source anterior segment optical coherence tomography system, shifts in myopic and astigmatic myopic eyes implanted with a pIOL with vaulting lower than 100 μm in miosis and more than 4 years of follow-up were dynamically evaluated. Main outcome measures were pIOL dynamic vault (vault interval and vault range [VR]), crystalline lens density, and anterior subcapsular lens opacities. Crystalline lenses were examined under slitlamp microscopy, and lens density was evaluated using quantitative Scheimpflug images. Scheimpflug images were compared with those of a control group comprising eyes that were candidates for pIOL implantation.

RESULTS

The study population comprised 24 eyes from 16 patients previously implanted with a pIOL (5.82 ± 0.9 years) with central vault lower than 100 μm under photopically induced miosis. The mean vault value was 52 ± 19 µm under photopic light conditions and 113 ± 37 µm under scotopic conditions. The mean VR was 58 ± 24 μm. Anterior subcapsular lens opacities were found in only 1 eye (4.17%). The mean lens density was 7.94 ± 0.43, and no statistically significant differences were observed compared with the control group.

CONCLUSIONS

Long-term low vaulting in eyes implanted with a pIOL with a central port for correction of myopia was associated with a low risk for developing anterior crystalline lens opacities.

Comparison of clinical outcomes of implantable collamer lens implantation with and without use of an ophthalmic viscosurgical device

PURPOSE

To compare the clinical efficacy of posterior chamber phakic implantable collamer lens (ICL) implantation with and without the use of an ophthalmic viscosurgical device (OVD).

SETTING

Onnuri Eye Hospital, Jeonju, Jeollabuk-do, South Korea.

DESIGN

Retrospective case series.

METHODS

Included were patients who underwent ICL implantation with the use of an OVD (OVD group) and patients who underwent ICL implantation without the use of an OVD (hydro group). Refractive error, endothelial cell density (ECD), intraocular pressure (IOP), vault, and adverse events were evaluated at 1 day, 1 week, 1 month, and 3 months postoperatively. The IOP and vault were checked 1 hour postoperatively, and the surgical time was recorded.

RESULTS

The OVD group comprised 54 eyes of 27 patients and the hydro group 49 eyes of 25 patients. There were no significant preoperative differences between the 2 groups. At 1 hour postoperatively, the IOP was significantly higher in the OVD group (P < .001); however, there was no significant difference in IOP between the 2 groups at other follow-up timepoints. Surgical time was significantly shorter for the hydro group (P = .032). There was no statistically significant difference in vault, ECD, or refractive error between the 2 groups during the 3-month follow-up period. No adverse events were observed.

CONCLUSIONS

ICL implantation without the use of an OVD was safe and effective. The advantages of this technique included a short surgical time, prevention of early postoperative IOP spikes, and cost savings due to OVD elimination.

Biometric and ICL-related risk factors associated to sub-optimal vaults in eyes implanted with implantable collamer lenses

Background

To identify biometric and implantable collamer lens (ICL)-related risk factors associated with sub-optimal postoperative vault in eyes implanted with phakic ICL.

Methods

This study reports a retrospective case series of the first operated eye in 360 patients implanted with myopic spherical or toric ICL. Preoperatively, white-to-white (WTW), central keratometry (Kc) and central corneal thickness (CCT) were measured using the Pentacam. Anterior-segment optical coherence tomography (AS-OCT, Visante) was applied preoperatively for measuring the horizontal anterior-chamber angle-to-angle distance (ATA), internal anterior chamber depth (ACD), crystalline lens rise (CLR), anterior-chamber angle (ACA) and postoperatively the vault. Eyes were divided into three vault groups: low (LVG: ≤ 250 μm), optimal (OVG: > 250 and < 1000 μm) and high (HVG: ≥ 1000 μm). Multinomial logistic regression (MLR) was used to find the sub-optimal vault predictors.

Results

MLR showed that CLR, ICL size minus the ATA (ICL size-ATA), age, ICL spherical equivalent (ICLSE) and ICL size as contributing factors for sub-optimal vaults (pseudo-R² = 0.40). Increased CLR (OR: 1.01, CI: 1.00–1.01) and less myopic ICLSE (OR: 1.22, CI: 1.07–1.40) were risk factors for low vaults. Larger ICL size-ATA (OR: 41.29, CI: 10.57–161.22) and the 13.7 mm ICL (OR: 7.08, CI: 3.16–15.89) were risk factors for high vaults, whereas less myopic ICLSE (OR: 0.85, CI: 0.76–0.95) and older age (OR: 0.92, CI: 0.88–0.98) were protective factors.

Conclusion

High CLR and low ICLSE were the major risk factors in eyes presenting low vaults. In the opposite direction, ICL size-ATA was the major contributor for high vaults. This relationship was more critical in higher myopic ICLSE, younger eyes and when 13.7 mm ICL were used. The findings show that factors influencing the vault have differentiated weight of influence depending on the type of vault (low, optimal or high).

Supplementary Information

The online version contains supplementary material available at 10.1186/s40662-021-00250-6.

Seven-year follow-up of posterior chamber phakic intraocular lens with central port design

BACKGROUND

To assess the clinical outcomes of the Visian Implantable Collamer Lens (ICL) with a central port throughout 7 years of follow-up.

METHODS

Eighty-four eyes of 52 patients were evaluated over a follow-up period of 7 years after V4c ICL implantation. Uncorrected (UDVA) and corrected (CDVA) distance visual acuities, refraction, intraocular pressure (IOP), endothelial cell density (ECD) and vault were analysed.

RESULTS

The mean postoperative UDVA (logMAR) was 0.04 ± 0.11, 0.13 ± 0.19 and 0.17 ± 0.23 at 1-, 5- and 7-years, respectively (P < 0.0001). The mean CDVA (logMAR) remains unchanged throughout a 7-year follow-up period (0.02 ± 0.08 and 0.02 ± 0.08, at 5- and 7-years, respectively, P = 0.2). At all follow-up visits, more than 95% of the eyes achieved a CDVA of 20/25 or better and more than 85% a CDVA of 20/20. At the end of the follow-up (7 years), no eye lost more lines of CDVA, 56 eyes (66.7%) and 28 eyes (33.3%) gained lines of CDVA. At 7-years, the spherical equivalent was - 0.62 ± 0.62 D. No significant increase in IOP (> 20 mmHg or an increase higher than 5 mmHg) occurred in any case throughout the 7-year of follow-up. The loss in ECD from the preoperative baseline at the last follow-up visit was 2.6%. No intraoperative or postoperative complications or adverse events occurred during the follow-up period.

CONCLUSIONS

The outcomes of this study show the long-term viability of the V4c ICL implantation as a surgical option for the correction of myopia.

Changes in anterior lens density after Implantable Collamer Lens V4c implantation: a 4-year prospective observational study

PURPOSE

To investigate the changes in anterior lens density with a Pentacam after Implantable Collamer Lens (ICL) V4c implantation in patients with myopia.

METHODS

This prospective case series examined 62 eyes of 32 patients (mean age, 28.5 ± 5.73 years) with myopia or myopic astigmatism after ICL V4c implantation. Uncorrected distance vision acuity, corrected distance vision acuity (CDVA), manifest refraction, intraocular pressure, anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), endothelial cell density and Pentacam images of lens density were obtained pre- and postoperatively. The vault was obtained during the follow-ups.

RESULTS

Patients were followed up for an average of 51 ± 2.7 months (range, 48-57 months). All surgeries were uneventful, without any complication. The efficacy and safety indices at the last follow-up were 1.03 ± 0.2 and 1.22 ± 0.22, respectively. No eye had decreased CDVA, and 66% eyes gained ≥1 line. Furthermore, refractive error in 90% eyes was within ±0.50 D and that of 100% was within ±1.0 D of the attempted refraction. Anterior average lens density (a-ALD) in the 0.5-, 1.0- and 1.5-mm depth zones increased by 10.41 ± 11.51%, 17.1 ± 11.09% and 16.76 ± 10.4%, respectively, compared to preoperative values (all p < 0.05). The change in a-ALD between two different age groups was not significant. Moreover, there were no significant correlations between the change in a-ALD and age, preoperative spherical equivalent, ACD, ACA, ACV or vault.

CONCLUSIONS

Implantable Collamer Lens (ICL) V4c implantation demonstrates safety and efficacy for myopia correction. Although a-ALD increased slightly at 4 years postoperatively, no cataract developed during the follow-up. Further studies should investigate the reason for the postoperative increase in a-ALD.

Clinical Prediction of Excessive Vault After Implantable Collamer Lens Implantation Using Ciliary Body Morphology

PURPOSE

To determine the factors related to the ciliary body that are predictive of outcomes of excessive vault (> 1,000 µm) after Implantable Collamer Lens (ICL V4c; STAAR Surgical) implantation.

METHODS

In this retrospective case-control study, 27 eyes of 27 patients who presented with excessive vault (> 1,000 µm) following implantation of an ICL V4c were matched in a 1:2 ratio with those who presented with a normal vault (250 to 1,000 µm) on white-to-white distance, anterior chamber depth, and ICL size. The preoperative biometric parameters and clinical outcomes were compared between the two groups. The relationship between the postoperative vault and various variables was assessed by multiple linear regression analysis. Conditional logistic regression models were used to estimate odds ratios (ORs) and 95% CIs for excessive vault.

RESULTS

The vault value 1 month postoperatively was associated with preoperative anterior chamber volume, iris-ciliary angle, and crystalline lens rise (P < .05). In the conditional regression logistic analysis, every 1° reduction in iris-ciliary angle was associated with 4% increased odds of vault greater than 1,000 µm (OR = 0.96; 95% CI = 0.93 to 0.99; P < .001) and the anteriorly positioned ciliary body was associated with an increased risk of excessive vault after ICL implantation (OR = 3.57; 95% CI = 1.67 to 7.63; P < .001). In the excessive vault group, 1 eye underwent the ICL extraction and 3 eyes had an ICL exchange for a smaller ICL. After the ICL exchange, the mean value of postoperative vault decreased from 1,525.67 ± 468.22 to 810.33 ± 254.92 µm.

CONCLUSIONS

Eyes with an anteriorly positioned ciliary body were associated with a higher rate of excessive vault after ICL implantation, so the size of the ICL may need to be adjusted in these patients. Assessment of ciliary body characteristics adds significant information to the prediction of excessive vault after surgery. [J Refract Surg. 2020;36(6):380-387.].

Comparison of anterior chamber angle changes following phakic intraocular lens with and without a central hole implantation for moderate to high myopic eyes

The aim of this study was to compare the anterior chamber angle changes after implantation of phakic intraocular lens with and without a central hole for moderate to high myopic eyes in Chinese people.This study enrolled 106 eyes of 54 people with intraocular lens V4 implantation and 105 eyes of 53 people with intraocular lens V4c implantation. Postoperative vault, intraocular pressure, and anterior chamber angle changes were assessed using noncontract tonometer and ultrasound biomicroscope, respectively, at 1, 3, 6, and 12months after the surgery.There were no significant differences (all P > .05) between the 2 groups in the depth of the central vault, intraocular pressure, or the width of anterior chamber angle at any time point post-surgery. The anterior chamber angle width in degree had a baseline of 54.40 ± 10.51 in V4c group, and decreased to 27.80 ± 5.62, 26.95 ± 5.56, 27.32 ± 5.66, 27.04 ± 5.47 at 1, 3, 6, and 12 months post-surgery, respectively. Mean preoperative value of 50.62 ± 11.77 decreased to 27.28 ± 6.53, 26.82 ± 6.03, 26.61 ± 5.80, 26.83 ± 5.76 at 1, 3, 6, 12 months, respectively, in V4 group. It had sufficient evidence (P < .001) that anterior chamber angle will narrow done after surgery, but there were no statistically significant differences within groups at any time point after surgery.The anterior chamber angle changes of the V4c group was essentially equivalent to that of conventional V4 group, although implantation of both models will lead to the decrease in anterior chamber angle width.

Posterior-Chamber Phakic Intraocular Lens Implantation in Patients over 40 Years of Age

Purpose

To assess the efficacy, safety, and predictability of the Visian Implantable Collamer Lens (ICL) model having a central port in patients over 40 years of age.

Methods

This study included 33 eyes from 21 patients who underwent V4c ICL implantation for the correction of myopia and myopic astigmatism. We assessed uncorrected (UDVA) and corrected (CDVA) distance visual acuity, refraction, intraocular pressure (IOP), endothelial cell density (ECD), vault, and adverse events occurring over a 1-year period.

Results

Mean age of the patients at the time of implantation was 43.52 ± 4.49 years (range: 40 to 56 years). Efficacy and safety indexes were 1 and 1.09, respectively. Surgical outcomes for CDVA were as follows: no eye lost any lines, 19 eyes (57.58%) showed no CDVA changes, 7 eyes (21.21%) gained 1 line, 4 eyes (12.12%) gained 2 lines, and 3 eyes (9.09%) gained ≥3 lines. Mean postoperative spherical equivalent (SE) was −0.09 ± 0.47 D. A total of 29 eyes (87.8%) were within ±0.50 D and 31 eyes (93.9%) were within ±1.00 D of the desired SE. At 1-year, mean IOP was 15.27 ± 3.03 mmHg (range: 9 to 20 mmHg, p=0.12 pre vs. post) and mean ECD was 2516 ± 234 cells/mm² (p=0.29 pre vs. post). Mean postoperative vault was 320 ± 136 μm, with 201–300 μm being the most prevalent vault range for 9 eyes (31.03%). None of the eyes showed a vault >701 μm. There were neither intraoperative nor postoperative complications; in fact, all ICL implantation procedures were uneventful.

Conclusions

Our study's findings support the use of this lens in patients over 40 years of age. A long follow-up period is advisable to monitor ICL position relative to the crystalline lens.

Four-year observation of the changes in corneal endothelium cell density and correlated factors after Implantable Collamer Lens V4c implantation

Background

To evaluate the changes in corneal endothelium cell density (ECD) and the correlated factors after Implantable Collamer Lens (ICL) V4c implantation.

Methods

In this retrospective, consecutive study, 48 eyes of 25 patients with myopia who underwent ICL V4c implantation were enrolled. Patients were followed up for at least 4 years, during which manifest refraction, uncorrected distance visual acuity, corrected distance visual acuity (CDVA), intraocular pressure, ECD, anterior chamber depth, anterior chamber volume (ACV), anterior chamber angle (ACA), vault and distance from the corneal endothelium to the central ICL (C-ICL) were measured. Spearman’s correlation analysis was used to identify variables correlated with changes in ECD, and generalised estimating equation model adjusting within-patient intereye correlations was used to predict changes in ECD.

Results

All surgeries were performed safely with no complications during follow-up (average 52±2.9 months). Safety and efficacy indices were 1.23±0.22 and 1.04±0.16, respectively. No eyes had decreased CDVA, and 67% gained one or more lines. Further, 79% were within ±0.50 D, and 100% were within ±1.0 D of the attempted refraction. Additionally, a 4.03%±2.2% reduction in ECD compared with the preoperative value was observed at the last follow-up visit. Changes in ECD were significantly correlated with vault, C-ICL, change in ACA and change in ACV. Vault was the most significant factor for changes in ECD.

Conclusions

ICL V4c implantation is safe and effective for myopia correction. Anterior segment biometric parameters including the vault, ACA and C-ICL may influence changes in ECD; specifically, the vault plays a major role.