Changes in Objective Vault and Effect on Vision Outcomes after Implantable Collamer Lens Implantation: 1-Year Follow-up

Establishment of a new vault prediction formula after implantable collamer lens implantation based on factor analysis of multi-modal ophthalmic parameters of anterior and posterior chamber

BACKGROUND

To establish a novel vault prediction formula after implantable collamer lens (ICL) implantation that considers both anterior and posterior chamber characteristics with multi-modal parameters.

METHODS

A total of 103 and 65 eyes were included in the development and validation groups, respectively. Exploratory factor analysis was performed using data from optical coherence tomography and ultrasound biomicroscopy in the development group to synthesise summative factors with different clinical significance. Dominant original metrics with heavy loadings on significant factors (absolute value of the loading coefficient >0.5) were screened for multivariate linear regression models using a stepwise method. The newly derived formula was evaluated and compared to the NK and KS formulas in the validation group.

RESULTS

Six factors (anterior chamber angle, horizontal width, lens, iris, iridociliary complex and ciliary body) were generated after dimension reduction via factor analysis. Factors 2 (horizontal width), 3 (lens), and 5 (iridociliary complex) had a significant influence on the vault. When dominant metrics on these factors were screened for further model building, ICL size, anterior chamber width, crystalline lens rise, iris curvature, and iris-ciliary process distance were retained in the final formula, with an adjusted R2 of 0.698, a median absolute error of 81.97 mm, and a root-mean-square error of 103.35 mm.

CONCLUSIONS

Multiple intraocular components, including the lens, iris, and ciliary body, play important roles in vault determination. The new formula exhibits good accuracy for vault predictions and ICL size recommendations.

The Distribution of Crystalline Lens Rise in High Myopia Population and Its Influence on Vault After Implanting Intraocular Collamer Lens

INTRODUCTION

As a result of the insufficient ocular anatomical parameters used to customize implantable collamer lens (ICL), many patients still cannot achieve a suitable vault after ICL implantation surgery. This study analyzed the characteristics of a new anatomical parameter crystalline lens rise (CLR) in a population with high myopia and explored the influence of CLR on the vault after ICL implantation.

METHODS

Patients (298 eyes) with high myopia who underwent ICL implantation were enrolled to study CLR characteristics. Postoperatively, patients (159 eyes) were divided into five groups according to the value of CLR (A, CLR ≤ - 150; B, - 150 < CLR ≤ 0; C, 0 < CLR < 150; D, 150 ≤ CLR < 300; E, CLR ≥ 300 μm), and to investigate the correlation between CLR and vault.

RESULTS

In the 298 eyes, the CLR had a normal distribution (P = 0.35) and the mean CLR was 67.93 ± 150.66 μm. Ninety-nine eyes (33.22%) had a CLR ≤ 0 μm, of which 20 eyes (6.71%) had a CLR ≤ - 150 μm; 199 eyes (66.78%) had a CLR > 0 μm, of which 20 eyes (6.71%) had a CLR ≥ 300 μm. In 159 eyes, the CLR was negatively correlated with the vault at 1 day (R = - 0.497, P < 0.001), 3 months (R = - 0.505, P < 0.001), and 6 months (R = - 0.505, P < 0.001) postoperatively. At 6 months, the vault of group A was statistically significantly different compared to groups B-E (all P < 0.05), and that of group E was statistically significantly different compared to groups A-D (all P < 0.001). The remaining groups did not show statistically significant differences (all P > 0.05).

CONCLUSION

The CLR had a normal distribution in the high myopia population, and 13.42% of the CLR values were extreme (CLR ≤ - 150 μm or CLR ≥ 300 μm). A larger ICL diameter than that recommended by the manufacturer should be considered when the CLR is ≥ 300 μm and a smaller ICL diameter should be considered when the CLR is ≤ - 150 μm.

Effect of vault on predicting postoperative refractive error for posterior chamber phakic intraocular lens based on a machine learning model

PURPOSE

To investigate how vault and other biometric variations affect postoperative refractive error of implantable collamer lenses (ICLs) by integrating artificial intelligence and modified vergence formula.

SETTING

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

DESIGN

Artificial intelligence and big data-based prediction model.

METHODS

2845 eyes that underwent uneventful spherical ICL or toric ICL implantation and with manifest refraction results 1 month postoperatively were included. 1 eye of each patient was randomly included. Random forest was used to calculate the postoperative sphere, cylinder, and spherical equivalent by inputting variable ocular parameters. The influence of predicted vault and modified Holladay formula on predicting postoperative refractive error was analyzed. Subgroup analysis of ideal vault (0.25 to 0.75 mm) and extreme vault (<0.25 mm or >0.75 mm) was performed.

RESULTS

In the test set of both ICLs, all the random forest-based models significantly improved the accuracy of predicting postoperative sphere compared with the Online Calculation & Ordering System calculator ( P < .001). For ideal vault, the combination of modified Holladay formula in spherical ICL exhibited highest accuracy ( R = 0.606). For extreme vault, the combination of predicted vault in spherical ICL enhanced R values ( R = 0.864). The combination of predicted vault and modified Holladay formula was most optimal for toric ICL in all ranges of vault (ideal vault: R = 0.516, extreme vault: R = 0.334).

CONCLUSIONS

The random forest-based calculator, considering vault and variable ocular parameters, illustrated superiority over the existing calculator on the study datasets. Choosing an appropriate lens size to control the vault within the ideal range was helpful to avoid refractive surprises.

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.

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.

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.

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.

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.

Clinical observations of EVO-ICL implantation and changes in corneal astigmatism using a modified technique

Background

Implantable collamer lens (ICL) surgery techniques are constantly progressing. The purpose of this study was to investigate the application effect of the modified technique and its impact on the change in corneal astigmatism in EVO-ICL surgery.

Methods

The analysis of retrospective cohort data included 153 eyes of 81 patients with myopia from July 2018 to May 2020. An EVO-ICL was inserted by modified surgical skills, including a single 3.0 mm corneal incision and no ophthalmic viscosurgical device (OVD) before the insertion of the ICL (modified technique group: 41 cases, 80 eyes) and standard procedure (standard technique group: 40 cases, 73 eyes). Early postoperative intraocular pressure (IOP) was monitored at 2 and 24 h. IOP, corrected distance visual acuity (CDVA), uncorrected distance visual acuity (UDVA), vault, and anterior chamber depth (ACD) were measured 1, 6, and 12 months following the initial examination. The corneal endothelial cell density (ECD) was monitored at 6 and 12 months after the operation. Surgically induced astigmatism (SIA) in the total, anterior, and posterior corneal surfaces was analysed 1 month after the operation.

Results

No serious complications were detected. The two groups had no difference in visual outcomes, ICL vaults, or ACD at any time point (P > 0.05). Two hours postoperatively, IOP was significantly lower in the modified technique group (16.22 ± 2.22 vs. 18.37 ± 1.92 mmHg, P < 0.05) than in the standard technique group. IOP decreased gradually after 24 h to preoperative levels. The postoperative IOP remained stable over a 12-month period. The ECD at 6 and 12 months was not significantly different between the groups (P > 0.05). SIA in the total, anterior, and posterior corneal surfaces were assumed to have no clinically meaningful differences between groups at one month after operation (P > 0.05).

Conclusions

The modified technique is efficient and safe, producing comparable visual and structural outcomes without adversely affecting ECD, and reduces fluctuations in IOP at the early postoperative stages. The auxiliary incision in the standard technique does not increase corneal SIA, which is also a factor to consider for inexperienced surgeons.

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.

Long-term Clinical Outcomes of Implantable Collamer Lens

Purpose: To evaluate the long-term clinical outcomes of implantable collamer lens (ICL) implantation in myopic patients.Methods: This retrospective study included 129 eyes of 68 patients who underwent ICL implantation for correction of myopia with a 10-year follow-up.Results: Ten years after ICL implantation, the mean uncorrected and corrected distance visual acuities (LogMAR) were 0.03 ± 0.13 and -0.07 ± 0.06, respectively. Ten years postoperatively, 52.7% and 84.5% of the eyes were within ± 0.5 and ± 1.0 diopters, respectively. The mean efficacy and safety indices were 0.91 ± 0.22 and 1.07 ± 0.19, respectively. There was no significant difference between mean preoperative (13.52 ± 2.88 mmHg) and postoperative (13.59 ± 3.55 mmHg) intraocular pressures. The endothelial cell density decreased from before surgery to 10 years after surgery (3,074 ± 365 cells/mm2, 2,812 ± 406 cells/mm2, respectively; mean decrease: 8.5 ± 10.8%; p = 0.011). Eight eyes (6.2%) developed cataract during follow-up, which was symptomatic in three eyes (2.3%) and treated with ICL explantation and phacoemulsification. Rhegmatogenous retinal detachment occurred in one eye (0.8%) and was treated with vitrectomy.Conclusions: ICL implantation for the correction of myopia had good efficacy and safety outcomes during long-term follow-up of 10 years. However, patients should be closely monitored for complications such as cataract formation, endothelial cell loss, and retinal detachment.

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.

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.

Agreement between optical coherence and Scheimpflug tomography: Vault measurements and reproducibility after implantable collamer lens implantation

PURPOSE

To evaluate the agreement between Scheimpflug tomography (Pentacam, Oculus) and anterior segment optical coherence tomography (AS-OCT, RTVue 100, Optovue) as well as the reproducibility of each technique in assessing the lens-ICL distance (vault) after implantable collamer lens (ICL) implantation.

METHODS

The vault was measured manually with Scheimpflug tomography and AS-OCT. Intraclass correlation coefficients (ICC) and Bland-Altman plots were used to determine the reproducibility of measurements and the agreement between them. Multivariate regression analysis was performed to identify predictors of differences in vault measurements between devices.

RESULTS

80 eyes of 46 ICL patients were analyzed. Mean patient age was 33.8±7.4 years (range, 21 to 51), and 27 (59%) were women. The preoperative spherical equivalent refraction ranged from -26 to 8.5 diopters (D). The mean vault measured by AS-OCT was 558.8±240.2μm (range, 162 - 1220) vs. 430.1±215.3μm (range, 0 to 1070) by Pentacam. AS-OCT yielded vault values, on average, 128.1±64.6μm higher than the Pentacam (range, -22 to 293μm). The ICC values for consistency and absolute agreement were 0.960 and 0.928, respectively. Reproducibility of vault measurements was excellent for both devices (ICC≥0.946). Four parameters-vault, pupil diameter (PD), PD differences between devices, and preoperative spherical equivalent refraction-were significant predictors of differences in vault measurements (adjusted-R²=0.412; P<0.001).

CONCLUSIONS

Agreement between AS-OCT and Pentacam for vault measurement was good. Vaults were higher when measured by AS-OCT. These differences are clinically relevant, and therefore these devices cannot be used interchangeably to measure vault.

Prediction of Phakic Intraocular Lens Vault Using Machine Learning of Anterior Segment Optical Coherence Tomography Metrics

PURPOSE

To compare the achieved vault using the conventional manufacturer's nomogram and the predicted vault using machine learning, in a large cohort of eyes undergoing posterior chamber phakic intraocular lens (EVO implantable collamer lens [ICL]; STAAR Surgical) implantation.

DESIGN

Reliability and validity assessment and comparison.

METHODS

Our study comprised a total of 1,745 eyes of 1,745 consecutive patients (mean age ± standard deviation, 26.2 ± 6.8 years) undergoing ICL implantation. At 1 month postoperatively, we quantitatively measured the actual vault, and compared it with the predicted vault using machine leaning of anterior segment optical coherence tomography metrics.

RESULTS

All machine learning methods, such as support vector regressor (SVR), gradient boost regressor (GBR), random forest regressor (RFR), and linear regressor (LR), showed significantly less mean absolute error and higher percentages of eyes within 50-200 µm of the targeted ICL vault than the conventional nomogram (P < .001). The RFR provided the lowest mean absolute errors and the highest percentages of eyes within 50 to 200 µm, followed by the GBR, the LR, and the SVR (P < .01).

CONCLUSIONS

Machine learning of the preoperative anterior segment optical coherence tomography metrics, especially the RFR, provided significantly higher predictability of the ICL vault than the conventional manufacturer's nomogram, suggesting that it will become an aid for predicting the ICL vault and subsequently selecting the proper ICL size in daily practice.

Refractive outcomes of implantation of an implantable phakic copolymer lens with peripheral holes in the intraocular posterior chamber in moderate to high myopia patients: a single-surgeon series

Purpose

To assess the safety and efficacy of implanting implantable phakic copolymer lenses (IPCLs) with peripheral optic holes in the intraocular posterior chamber in Indian patients with moderate to high myopia.

Methods

Seventy-five eyes of 50 patients who underwent IPCL implantation were retrospectively analyzed. Preoperative parameters, such as subjective refraction, anterior chamber depth (measured using a pentacam), and white-to-white diameter were measured. A custom-made IPCL using the aforementioned parameters was then implanted in the sulcus to correct moderate to high myopia. All patients had undergone neodymium-doped yttrium aluminum garnet peripheral iridotomy.

Results

Clinical outcome data were collated retrospectively from the medical case records of the patients. The mean age was 25.36 years (standard deviation [SD]: 3.60 years), and 55.55% of the patients were men. The mean preoperative best-corrected visual acuity (BCVA) was 0.367 logmar units (SD: 0.266, max: 0.0 and min: 1.2). The post-IPCL implantation mean uncorrected visual acuity was 0.225 logmar units (SD: 0.172, max: 0 and min: 0.7), which was significantly superior to the preoperative BCVA (P=<0.0001). Forty-three patients (86%; satisfaction scores of ≥4; scale 1-5) were "highly satisfied" to "extremely satisfied" with the outcome. The mean follow-up period was 1.8 years.

Conclusion

Implantation of the IPCL with peripheral holes in the intraocular posterior chamber resulted in a clinically significant improvement in unaided visual acuity. Long-term follow-up showed optimum stability of vision.

Optimization of the lens sizing for the second eye based on the vault obtained in the first eye in bilateral myopic collamer phakic intraocular lens surgery

PURPOSE

To assess vault and the decision-making process involved in selecting the size of the lens for the fellow eye in a series of patients who received bilateral phakic collamer intraocular lens (pIOL) implants with central hole for correction of myopia.

METHODS

The study sample included all patients who underwent bilateral insertion of a different size pIOL from a pool of 269 patients who underwent sequential bilateral insertion of a pIOL from March 2012 to May 2015 in our institution. Procedures were separated in time to assess the value of the vault and select the pIOL size in second eyes. Vault was analysed objectively using optical coherence tomography.

RESULTS

The decision to change the size of the pIOL in the fellow eye was taken in 25 patients. A smaller pIOL was implanted in the second eye in 9 patients, whereas a lens that was 1 size larger was necessary in 16 patients. Implantation of a larger lens led to a mean increase in vault of 251 ± 180 microns; implantation of a smaller size lens led to a mean decrease in vault of 542 ± 187 microns. In 5 patients, the pIOL implanted in first eye was rotated vertically to reduce lens vault. No lenses had to be explanted.

CONCLUSIONS

Vault in fellow eyes can be improved in patients receiving bilateral myopic pIOL implants by modifying the pIOL size based on the vault value obtained in the first eyes.

Analysis of intraocular positions of posterior implantable collamer lens by full-scale ultrasound biomicroscopy

Background

To analyze the positions of intraocular posterior Implantable Collamer Lens (ICL) and its possible relationship with vault.

Methods

This cross-sectional study included 72 patients with high myopia (134 eyes) who were followed up after phakic intraocular lens implantation. The postoperative time ranged from 1 week to 7 years. We obtained the images of ICL by using Compact Touch STS UBM and observed the position of ICL in posterior chamber and ciliary sulcus. The horizontal lines vault was measured and recorded.

Results

There were various positions in the posterior chamber as observed by full-scale ultrasound biomicroscopy and the haptics were inserted at different positions. -Eight seven eyes (64.9%) that obtained ideal vault, 29 eyes (21.6%) had insufficient vaults and 18 eyes (13.4%) had excessive vault. The vault with various positions of haptics was in ideal range (250 μm–750 μm) almost in each group. Three eyes in this study with haptics on the top of ciliary sulcus obtained excessive vault (mean vault, 850.00 ± 70.71 μm) and one eye appeared one side haptics pushing forward the iris. Among five eyes (3.7%) with iridociliary body cysts, three eyes (60%) obtained ideal vault. One eye (0.7%) with ICL decentralization after implantation surgery had an ideal vault, but the patient had serious glare.

Conclusions

Though ICL in the posterior chamber had different positions and the haptics in most cases were not in the ciliary sulcus, the postoperative vault was almost in the ideal range.

Comparison Over Time of Vault in Chinese Eyes Receiving Implantable Contact Lenses With or Without a Central Hole

PURPOSE

To compare the longitudinal vault changes after implantation of a posterior chamber phakic intraocular lens (pIOL) (Visian implantable contact lens) with (ICL V4c) and without (ICL V4) a central artificial hole for moderate to high myopia in Chinese eyes.

DESIGN

Retrospective case series.

METHODS

This study comprised 78 eyes implanted with the ICL V4c model and 82 eyes implanted with the ICL V4 model at our department by the same surgeon. The time course of the postoperative pIOL vault changes was quantitatively assessed using ultrasound biomicroscopy over 6 months.

RESULTS

There was a trend toward a decrease in all measures of central vault, peripheral vault, and the endothelium-anterior pIOL distance for both central hole pIOL and conventional pIOL over time, although the variance was not statistically significant (all P > .05). There were no significant between-group differences in the amount of the pIOL central vault, peripheral vault, or the endothelium-anterior pIOL distance at any time point after surgery (all P > .05).

CONCLUSIONS

The time course of the central hole pIOL vault changes is essentially equivalent to that of the conventional pIOL vault, suggesting that the presence of the central hole did not significantly affect the pIOL position.

Comparison of early changes in and factors affecting vault following posterior chamber phakic Implantable Collamer Lens implantation without and with a central hole (ICL V4 and ICL V4c)

Background

To objectively compare the early changes in vault over time following implantation of an Implantable Collamer Lens without (ICL V4) and with (ICL V4c) a central hole and the respective factors affecting vault change in moderate to high myopia.

Methods

This prospective study comprised of 38 eyes of 38 patients implanted with ICL V4 and 39 eyes of 39 patients implanted with ICL V4c intraocular lenses. We quantitatively assessed the postoperative values of vault and pupil size at 1 day, 1 week, and 1 month following implantation using a rotating Scheimpflug camera (Pentacam). We compared these postoperative values within and between the two groups and identified the factors affecting vault change.

Results

The mean vaults at 1 day, 1 week, and 1 month following ICL V4 implantation were 303.68 ± 185.11, 517.89 ± 160.07 and 521.32 ± 155.72 μm respectively, and those following ICL V4c were 316.67 ± 186.89, 495.13 ± 180.84 and 510.77 ± 175.51 μm, respectively. There was a significant difference in vault between 1 day and 1 week postoperatively. There was a significant association between the vault change and the pupil size change in both groups from 1 day to 1 month postoperatively (Pearman correlation coefficient; ICL V4: r = 0.585, P = 0.001; ICL V4c: r = 0.588, P <0.001). The vault value 1 month after implantation of ICL V4 and ICL V4c was associated with the preoperative anterior chamber depth, horizontal corneal diameter, horizontal and vertical sulcus-to-sulcus.

Conclusions

Pupil movement is a critical factor in vault change, with increasing vault observed postoperatively from 1 day to 1 week associated with the declining effects of pharmacological miosis and increasing pupil size. The anterior chamber depth, horizontal corneal diameter, horizontal and vertical sulcus-to-sulcus show some correlation with vault.

Electronic supplementary material

The online version of this article (doi:10.1186/s12886-016-0336-8) contains supplementary material, which is available to authorized users.

Meta-analysis and review: effectiveness, safety, and central port design of the intraocular collamer lens

The purpose of this review is to summarize relevant data from publications appearing in the peer-reviewed scientific literature over the past decade since US Food and Drug Administration approval of the implantable collamer lens (ICL), and, in particular, to review studies relating to sizing methodology, safety, and effectiveness, as well as more recent studies reporting clinical outcomes of the V4c Visian ICL with KS Aquaport, VICMO. A literature search was conducted using two databases, PubMed.gov and Science.gov, to identify all articles published after 2005 related to the Visian ICL (STAAR Surgical, Inc.). Articles were examined for their relevance to sizing methodology, clinical safety, and effectiveness, and the references cited in each article were also searched for additional relevant publications. The literature review revealed that all currently reported methods of determining the best-fit size of the ICL achieve similarly satisfactory results in terms of vault, the safe distance between the crystalline lens and the ICL. Specifically, meta-analysis demonstrated that sulcus-to-sulcus and white-to-white measurement-based sizing methods do not result in clinically meaningful nor statistically significant differences in vault (two-sample two-sided t-test using pooled mean and standard deviations; t (2,594)=1.33; P=0.18). The reported rates of complications related to vault are very low, except in two case series where additional risk factors such as higher levels of myopia and older age impacted the incidence of cataract. On the basis of preclinical studies and initial clinical reports, with up to 5 years of follow-up, the new VICMO central port design holds promise for further reduction of complications. Given its safety record and the significant improvement in vision and quality of life that the ICL makes possible, the benefits of ICL implantation outweigh the risks.