Middle- and long-term results after iris-fixated phakic intraocular lens implantation in myopic and hyperopic patients: a meta-analysis

Comparison of the Biometric Characteristics After Long-term Implantation of Iris-fixated Phakic Intraocular Lens in Explanted and Nonexplanted Groups of Eyes

PURPOSE

To evaluate and compare the biometric characteristics of the anterior chamber of a group of patients with significant endothelial cell loss (ECL) who required phakic intraocular lens (pIOL) explantation and a group of patients who did not fulfill the explantation criteria related to corneal decompensation.

DESIGN

Retrospective, consecutive, interventional case series.

METHODS

The study included all consecutive patients receiving a pIOL implantation at Oftalmosalud Instituto de Ojos, Lima, Peru, between 2001 and 2012. The explanted group (E group) consisted of eyes in which the pIOLs were explanted due to ECL, and the nonexplanted group (NE group) consisted of eyes randomly selected in which the pIOL was not explanted with a minimum follow-up time of 8 years. Slit-lamp biomicroscopy, visual acuity, refraction, endothelial cell count, and anterior segment optical coherence tomography were assessed at the preoperative evaluation for both groups and before explantation in the E group and 8 years post-implantation in the NE group.

RESULTS

pIOLs were implanted in 265 eyes. The annual percentage of ECL was 1.47% and 5.55% in the NE group and E group, respectively (P < .001). The mean minimum endothelial lens distance (ELD) was 1.44 ± 0.22 mm and 1.05 ± 0.23 mm in the NE group and E group, respectively (P < 0.001). The mean time for explantation was 12.58 ± 3.79 years for the E group. Annual ECL could accurately discriminate between the NE group and E group; a cutoff point of 3.5 (%/year) or 86.5 (cells/years) had a 100% sensitivity and specificity. A cutoff of 1.21 mm in the minimum ELD has a 91% sensitivity and 79% specificity to discriminate between the E group and NE group.

CONCLUSIONS

pIOL explantation due to ECL occurs in eyes with a significantly postoperative lower minimum ELD. Annual ECL and minimum ELC can effectively discriminate between the E and NE groups.

Endothelial Cell Loss in Patients with Phakic Intraocular Lenses

Although the safety of phakic intraocular lenses (pIOLs) has been continuously improved over 70-years of development, high endothelial cell losses can occur even with current pIOL models. Numerous studies have demonstrated that the distance of a pIOL to the corneal endothelium plays a crucial role in the extent of endothelial cell loss. For this reason alone, higher endothelial cell loss tends to be observed with anterior chamber lenses than with posterior chamber lenses. Adequate preoperative anterior chamber depth is essential, at least for iris-fixed pIOLs, in order to ensure a safe distance from the endothelium. However, the anterior chamber becomes shallower with age and therefore it may be useful to consider patient age in the safety criteria. Although endothelial cell loss is generally low with current pIOL models, regular monitoring of the endothelial cell density remains essential due to large interindividual differences in patients with pIOLs. If the endothelial cell loss is greater than expected and the follow-up visits confirm the trend, the pIOL should be explanted without delay. The endothelial reserve should be considered on an individual basis by taking into account patient age, physiological endothelial cell loss, and loss due to further surgery. With careful indication and long-term patient care, pIOLs remain a safe treatment option.

Long-term safety and efficacy of a foldable iris-fixated phakic intraocular lens for the correction of myopia

PURPOSE

To analyze and report the long-term outcomes in terms of efficacy and safety of eyes implanted with the spherical version of a foldable iris-fixated phakic intraocular lens (pIOL) for the correction of myopia.

METHODS

Retrospective analysis of the results of 56 eyes of 32 patients (age, 19-45 years) who underwent implantation of the spherical model of the Artiflex pIOL (Ophtec B.V., Groningen, The Netherlands) for the correction of myopia. Visual, refractive, biometric, intraocular pressure (IOP) and corneal endothelial changes were evaluated during a long-term follow-up: 2, 7, 10 and 12 years for more than 50, 30, 20 and 10 eyes, respectively.

RESULTS

At 4 weeks postoperatively, a significant reduction of manifest sphere and spherical equivalent (SE), with a significant improvement of uncorrected distance visual acuity were found (all p < 0.001). No significant changes were found during the rest of follow-up in sphere (p ≥ 0.072). The percentage of eyes with SE within ± 1.00 D was over 83% during the whole follow-up. A non-significant trend to IOP increase was observed at 4 weeks postoperatively (p = 0.530), with a significant reduction at 1 year after (p = 0.039) and no significant changes during the rest of follow-up (p = 0.180). There was a significant reduction of anterior chamber depth at 4 weeks after surgery (p < 0.001), with no significant changes during the following 9 years of follow-up (p = 0.118). However, an additional significant decrease of this parameter was observed between 10 and 13 years after surgery (p = 0.027). Mean endothelial cell loss changed from 2.01 ± 4.49% at 4 weeks after surgery to 9.11 ± 2.24% at the end of the follow-up. No complications were reported during the follow-up.

CONCLUSIONS

Myopia correction with the Artiflex pIOL is an effective and safe procedure in the long term.

Vault Height Is a Key Predictive Factor for Anterior Segment Measurement Error by IOLMaster 700 in Eyes With Phakic Intraocular Lens

Purpose

To identify risk factors of ocular anterior segment measurement error by the IOLMaster 700 in eyes implanted with an implantable Collamer lens (ICL).

Methods

In total, 152 patients with clear lens (152 eyes, group 1) and another 32 cataract patients (57 eyes, group 2) who underwent ICL implantation were included, and the presence of measurement error by the IOLMaster 700 was determined based on B-scan images. The risk factors for measurement error were evaluated by logistic regression, and the optimal threshold was determined using receiver operating characteristic analysis.

Results

The ICL was misidentified as the anterior surface of the crystalline lens in 51.97% of eyes (79/152) in group 1 and 80.70% of eyes (46/57) in group 2. For every 100-µm decrease in the vault height, a 3.57- and 5.78-fold increase in the risk of measurement error was observed in group 1 and group 2, respectively. We identified an optimal threshold of the vault height at 389.47 µm for predicting biometric measurement error in eyes implanted with ICL, which showed an area under the curve of 0.93 (95% confidence interval, 0.90-0.97), a sensitivity of 0.87, and a specificity of 0.86.

Conclusions

Patients with ICL implantation, particularly those with a vault height less than 389.47 µm, are at a greater risk of anterior segment biometric measurement error by the IOLMaster 700.

Translational Relevance

The threshold of vault height can help to identify high-risk patients and further optimize biometric measurement.

Long-Term Follow-Up of Corneal Endothelial Cell Changes After Iris-Fixated Phakic Intraocular Lens Explantation

PURPOSE

The purpose of this study was to evaluate long-term corneal endothelial cell changes and visual outcomes after iris-fixated phakic intraocular lens (pIOL) explantation in patients with endothelial damage and to investigate potential predictors of endothelial injury.

METHODS

Consecutive patients undergoing pIOL explantation with corneal endothelial cell density (ECD) <2000 cells/mm 2 at the time of the procedure were retrospectively reviewed in a single tertiary center. All patients were treated between April 2016 and October 2020 at a high-volume referral-based tertiary hospital. The primary outcome was the change in corneal endothelial parameters, including ECD, over long-term follow-up. Secondary outcomes included changes in corrected distance visual acuity and analysis of prognostic factors.

RESULTS

This study included 44 eyes from 28 patients with an average age of 42.5 ± 7.8 years (range: 27-63). Mean ECD before explantation was 1375.4 ± 468.2 cells/mm 2 (range: 622-1996), and the average duration of follow-up after explantation was 20.5 months (6-58.2). Two years after explantation, ECD had significantly decreased by more than 25% to 1019.6 ± 368.6 (608-1689; P < 0.01). However, there was no significant change in corrected distance visual acuity (20/23-20/22, P = 0.59). Longer operation duration (odds ratio, 1.004; P = 0.04) was the only significant factor weakly associated with postoperative decreases in ECD.

CONCLUSIONS

Although ECD continuously decreased despite pIOL explantation on a long-term follow-up, patients did not experience any discomfort or showed decreases in visual acuity. Therefore, a careful follow-up is required for possible endothelial injury after pIOL explantation.

Long-term efficacy and safety profiles of iris-fixated foldable anterior chamber phakic intraocular lens implantation in eyes with more than 10 years of follow-up

PURPOSE

To evaluate the long-term efficacy, safety, predictability, and stability of a foldable anterior chamber phakic intraocular lens (pIOL) (Artiflex) implantation in eyes with more than 10 years of follow-up.

SETTING

Instituto de Microcirugía Ocular, Barcelona, Spain.

DESIGN

Retrospective study.

METHODS

Patients who underwent Artiflex pIOL implantation during 2008 to 2011 and with more than 10 years of follow-up were included. Variables analyzed were as follows: uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, spherical equivalent (SE), endothelial cell count (ECC), and intraocular pressure (IOP) preoperatively and at 1 month, 1 year, 5 years, and the final follow-up. Descriptive statistics were performed and results reported following the Standard for Reporting Refractive Surgery Outcomes.

RESULTS

76 eyes (40 patients) were analyzed, and the mean follow-up was 10.67 ± 0.64 years. The mean preoperative SE was -8.26 ± 2.47 diopters (D), and the mean preoperative cylinder was -0.95 ± 0.86 D. At the final follow-up, efficacy and safety indices were 0.82 and 1.11, respectively. In total, 58 eyes (76%) achieved a UDVA of ≥20/40. 30 eyes (39%) gained ≥1 line of CDVA, and no eye lost ≥2 lines of CDVA. At the final follow-up, 46 (61%) and 58 (76%) eyes were within ±0.50 D and ±1.00 D of attempted SE correction, respectively. 72 eyes (95%) had ≤1.00 D of postoperative astigmatism, and 46 eyes (61%) were within ±15 degrees from the intended correction axis. At the last visit, a statistically significant myopic progression of -0.56 ± 0.83 D was observed ( P = .01). The mean ECC loss at the final follow-up was 12.2 ± 12.5%. IOP remained stable. Two eyes (2.63%) developed cataract after 10.3 years.

CONCLUSIONS

Long-term results demonstrated that Artiflex pIOL implantation was effective, predictable, stable, and safe.

Five-year clinical outcomes of rigid iris-fixated phakic intraocular lens in northern Chinese

PURPOSE

To investigate the 5-year clinic outcomes of rigid iris-fixated pIOL on the visual performance, complications and intraocular light scattering in northern Chinese.

METHODS

Thirty eyes implanted with iris-fixated phakic IOLs (pIOLs group) and 34 eyes with high myopia (myopia group) were involved in this study. At preoperatively, 6 months, 1, 3, and 5 years postoperatively, the uncorrected visual acuity (UCVA), best-spectacle corrected visual acuity (BSCVA), endothelial cell density (ECD), and intraocular pressure (IOP) were measured in pIOLs group. The objective scatter index (OSI), modulation transfer function cut off (MTF cut off), and Strehl ratio were measured by Optical Quality Analysis System and a pseudophakic dysphotopsia questionnaire (PDQ) was used to evaluate the subjects' satisfaction in pIOLs and myopia groups.

RESULTS

At 5 years postoperatively, an UCVA of 20/20 or better was found in 43.33% of eyes in pIOLs group. At 6 months, 1, 3, and 5 years postoperatively, the mean ECD decrease were 1.29% ± 0.45%, 2.59% ± 1.30%, 6.67% ± 2.26%, and 10.80% ± 3.48%. The value of OSI in pIOLs group was significantly higher than that in myopia group (P < 0.001). The PDQ results showed that the subjects in myopia group complained less with intolerance of bright lights than those in pIOLs group. The values of Strehl ratio and MTF cut off in pIOLs group were significantly lower than that in myopia group (P < 0.001).

CONCLUSIONS

Iris-fixated pIOL induce more intraocular light scattering. A significant decrease in ECD was observed at 5 years postoperatively. An annual evaluation of ECD is necessary for patients undergoing pIOL implantation.

Phakic intraocular lens explantation: a series of 175 surgeries

PURPOSE

The ideal timing for phakic intraocular lens (pIOL) explantation remains unknown. Our study aims to evaluate the indications for pIOL explantation, pIOL survival time, visual outcomes, and access endothelial cell loss (ECL) after explantation.

SETTING

Ophthalmology Department, Centro Hospitalar Universitário do Porto, Portugal. Design: Retrospective longitudinal study.

METHODS

Chart review was performed for all consecutive patients that underwent pIOL explantation from January 2010 to December 2019 in a single center.

RESULTS

This study included 175 eyes of 112 patients, 77% of which were female. Phakic IOL survival was 12.9 ± 4.8 [3.7 - 28.6] years and the follow-up period after explantation was 4.1 ± 3.0 [0.3 - 9.9] years. The most frequent causes for explantation were cataract formation (44.0%, n=77) and ECL (50.3%, n=88). During the follow-up period after explantation, mean ECL rate was 2.27 ± 9.32 %/year in the cataract group and -2.14 ± 10.24 %/year in the ECL group, reflecting a positive change in cell density in the latter. Eight eyes (4.6%) required a corneal transplant during the follow-up. Mean corrected distance visual acuity was 0.17 ± 0.24 logMAR at the last visit.

CONCLUSION

Our study demonstrates that pIOL explantation, after an average survival time of 13 years, is a safe procedure. The main causes for explantation were cataract formation and ECL. Most patients show a sustained improvement in visual acuity and endothelial cell density after pIOL explantation, and yet its timing should be ideal to avoid irreversible complications.

Toric intraocular lens for astigmatism correction following keratoplasty in phakic and pseudophakic eyes

ABSTRACT

Residual astigmatism and anisometropia significantly impact patients' vision and quality of life even in clear grafts after corneal transplant. We reviewed and summarized the role of toric intraocular lens (IOL) in phakic and pseudophakic eyes after penetrating keratoplasty (PKP) and deep anterior lamellar keratoplasty (DALK) in correcting residual astigmatism. We included 342 eyes from 20 studies with iris-clipped toric IOL, ciliary sulcus toric implantable collamer lens, piggyback sulcus toric IOL, or posterior chamber toric IOL implantations for phakic, pseudophakic, or eyes undergoing cataract surgery after keratoplasty. Visual, refractive, and predictability outcomes were encouraging. Secondary re-alignment rate and complications were low. Endothelial cell loss secondary to phakic toric IOL might be a concern over the long-term, particularly in iris-clipped IOL in PKP eyes. Toric IOL represent a viable option in the treatment of residual astigmatism in post-keratoplasty eyes, resulting in improved visual acuity and reduced anisometropia.

Accuracy of Intraocular Lens Calculation Formulas in Patients Undergoing Combined Phakic Intraocular Lens Removal and Cataract Surgery

PURPOSE

To investigate the prediction accuracy of intraocular lens (IOL) calculation formulas, and the impact of anterior chamber depth (ACD) and lens thickness (LT) measurement errors on IOL power calculation in patients undergoing combined phakic IOL (PIOL) removal and cataract surgery.

DESIGN

Retrospective, consecutive case series study.

METHODS

Thirty-six PIOL implanted eyes (12 anterior chamber PIOLs and 24 posterior chamber PIOLs [PC-PIOL]) undergoing cataract surgery were included. The prediction accuracy of new formulas (Barrett universal II, Emmetropia verifying optical, Kane, and Ladas super formula) and traditional formulas (Haigis, Hoffer Q, Holladay 1 and SRK/T) with or without Wang-Koch (WK) axial length (AL) adjustment was evaluated. The influence of ACD and LT measurement errors of IOLMaster 700 on refractive outcomes was also investigated.

RESULTS

The Kane and traditional formulas with WK AL adjustment had no significant systematic prediction error and displayed a smaller median absolute error, whereas the other formulas showed significant hyperopia shift (P < .05) and relatively lower prediction accuracy. The accuracy rate of IOLMaster 700 in measuring the ACD and LT was 100% in eyes with anterior chamber PIOL implantation, and 37.50% in the PC-PIOL subgroup. No significant difference was observed in refractive outcomes of formulas using correct and wrong parameters in the PC-PIOL subgroup (P > .05).

CONCLUSIONS

The Kane and traditional formulas with WK AL adjustment exhibited relatively higher prediction accuracy in patients who underwent combined PIOL removal and cataract surgery. The IOLMaster 700 displayed low accuracy in ACD and LT measurements for PC-PIOL implanted eyes, but showed negligible impact on IOL prediction accuracy.

Myopic Correction with Iris-Fixated Phakic Intraocular Lenses: Twelve-Year Results

PURPOSE

To evaluate a 12-year follow-up of myopic patients after iris-fixated phakic intraocular lenses (IF pIOLs) implantation. Setting. Ophthalmology Department, Military University Hospital in Prague (Czech Republic).

DESIGN

Single-center retrospective cohort study.

METHODS

We describe the results of a cohort study that included 85 eyes of 46 myopic patients who underwent implantation of Verisyse myopia, Veriflex, and Verisyse myopia toric (all Abbott Medical Optics, Inc.) intraocular lenses. Refractive functions and adverse events were assessed preoperatively, at 6 months, and 1, 2, 5, and 12 years after IF pIOL implantation.

RESULTS

Mean spherical equivalent was measured as -9.37 ± 2.87 D, 0.14 ± 0.61 D, and -0.42 ± 1.08 D, preoperatively, at 6 months and 12 years postoperatively, respectively. There was a significant reduction in the cylinder after surgery. At 12 years postoperatively, 90% of eyes had uncorrected distance visual acuity (UDVA) of 20/40 and 64% of 20/20. The safety index was 1.10 for the whole postoperative follow-up period. We found cataract formation in 3 eyes (3.5%). The endothelial cells loss (EC loss) directly caused by IF pIOL implantation was 6.0%, 8.10%, 12.8%, and 11.9%, at 1, 2, 5, and 12 years, respectively. In our cohort, 95% of eyes lost a higher percentage of EC than would be expected from a physiological loss at 12 years postoperatively. We found a significant negative interaction between preoperative pachymetry and EC loss, indicating that the lower pachymetry leads to a faster decline in endothelial cells density (ECD). IF pIOL re-enclavation was found in 28% of eyes. 7% of subluxations were caused by trauma. The mean time of nontraumatic re-enclavation was 6 years postoperatively.

CONCLUSIONS

The study confirmed the advantages of IF pIOL implantation due to rapid visual recovery and stable visual function over the 12-year follow-up and also showed the influence of lower corneal pachymetry regarding EC loss.

Short-Term Efficacy and Safety of Cataract Surgery Combined with Iris-Fixated Phakic Intraocular Lens Explantation: A Multicentre Study

The purpose of this study was to evaluate the short-term efficacy and safety of cataract surgery for patients with iris-fixated phakic intraocular lenses (pIOLs). This study included 96 eyes of 91 patients. The changes in the logMAR uncorrected visual acuity (UCVA), best-corrected visual acuity (BCVA), subjective spherical equivalent (SE), astigmatism, and endothelial cell density (ECD) were collected retrospectively. The intraoperative and postoperative complications also were investigated to assess the surgical safety. The preoperative UCVA and BCVA improved significantly at month 1 postoperatively, respectively (p < 0.001 for both comparisons). The efficacy and safety index at month 1 postoperatively were 1.02 ± 0.56 and 1.31 ± 0.64, respectively. The SE at month 1 postoperatively was significantly (p < 0.001) higher compared to preoperatively, whereas the subjective astigmatism did not differ significantly (p = 0.078). The ECD significantly decreased at month 1 (p < 0.001). The most common postoperative complication was intraocular pressure elevation exceeding 25 mmHg in 10.4% of eyes, which was controlled with medications in all cases until month 1 postoperatively. No intraoperative complications developed. Cataract surgeries for patients with iris-fixated pIOLs were performed safely with good visual outcomes.

Comparison of the visual performance of iris-fixated phakic lens and implantable collamer lens to correct high myopia

Background

To compare visual performance between the iris-fixated phakic intraocular len (pIOL) and implantable collamer len (ICL) to correct high myopia.

Methods

Twenty-four eyes underwent iris-fixated pIOL implantation and 24 eyes underwent ICL implantation. At the 6-month follow-up, the best-corrected visual acuity (BCVA) and uncorrected distance visual acuity (UDVA) were compared between the iris-fixated pIOL and ICL groups. The objective scatter index (OSI), modulation transfer function (MTF) cutoff, and ocular aberrations were performed to evaluate postoperative visual quality between the two groups.

Results

No significant difference was found in UDVA, BCVA, and spherical equivalent between the iris-fixated pIOL and ICL groups (P > 0.05). Six months after surgery, the following values were significantly higher in the ICL group than in the iris-fixated pIOL group: MTF cutoff, strehl ratio and optical quality analysis system values at contrasts of 9 %, 20 %, and 100 % (P < 0.01). The OSI in the iris-fixated pIOL group was higher than in the ICL group 6 months after surgery (P < 0.01). All high-order aberrations were slightly more severe in the iris-fixated pIOL group than in the ICL group 6 months after surgery, although only trefoil (P = 0.023) differed significantly in this regard.

Conclusions

Both iris-fixated lenses and ICLs can provide good visual acuity. ICLs confer better visual performance in MTF-associated parameters and induce less intraocular light scattering than iris-fixated pIOLs.

Implantation of an iris-fixated phakic intraocular lens for the correction of hyperopia: 15-year follow-up

PURPOSE

To assess the predictability, efficacy, stability, and safety of implantation of an Artisan iris-fixated phakic intraocular lens (IF-pIOL) for the correction of hyperopia with a follow-up of up to 15 years.

SETTING

Leiden University Medical Center, the Netherlands.

METHODS

Patients operated by a single surgeon up to 2007 were identified, and data on refraction, corrected distance visual acuity (CDVA), uncorrected distance visual acuity, endothelial cell (EC) density, and complications were collected.

RESULTS

A total of 61 eyes (32 patients) were analysed. The mean spherical equivalent decreased from +6.43 ± 1.78 diopters (D) preimplantation to -0.22 ± 0.57 D at 1 year postimplantation and remained stable throughout follow-up. A stable CDVA with safety indices ranging from 0.91 to 1.10 and efficacy indices between 0.43 and 0.86 were observed. Follow-up time had a significant effect on EC density with an estimated annual decline of 58 cells/mm2 after IF-pIOL implantation. IF-pIOL explantation was performed in a 10 eyes (16.4%) after 8.13 ± 5.11 years. The main reason for IF-pIOL explantation was EC loss (4 eyes [6.6%]). Pigment dispersion was the most encountered complication, observed in 9 eyes (14.8%).

CONCLUSIONS

Visual and refractive results after implantation of an IF-pIOL to correct hyperopia show favorable and stable results with long-term follow-up. Lifelong monitoring of EC counts is mandatory. Pigment dispersion might be a problem in hyperopic eyes implanted with an IF-pIOL; a shallower anterior chamber depth and a convex iris configuration might be predisposing factors.

Iris-fixated phakic intraocular lens explantation

BACKGROUND/AIMS

To evaluate the visual outcomes and indication for surgery in a series of patients who underwent explantation of a phakic intraocular lens (PIOL).

METHODS

A retrospective case series of patients who underwent PIOL explantation in our institution was performed. The indication for explantation and visual and refractive outcomes were examined. The method of explantation is described.

RESULTS

Twenty-two eyes of 16 patients underwent PIOL explantation with a mean time to explantation of 7 ± 3 years (range 3-11.4). The mean age at explantation was 50.3 ± 9.3 years. Sixteen Artisan PIOLs and six Artiflex PIOLs were explanted. The indications for explanation were cataract development (17/22), endothelial cell loss (4/22) and synechiae formation (1/22). All patients with cataract underwent a combined procedure with explantation and phacoemulsification and the placement of a posterior chamber IOL. Mean corrected vision after explantation was 0.22 ± 0.10 logMAR (range 0.1-0.3 logMAR). One patient with endothelial cell loss required a Descemet's Stripping Endothelial Keratoplasty (DSEK).

CONCLUSION

Removal of PIOLs was necessitated most frequently by cataract followed by endothelial cell loss. Both explantation alone and explantation with concurrent phacoemulsification are safe procedures with good visual outcomes and will become more frequent in the future as more patients with PIOLs reach cataractous age.