Comparison of three phakic intraocular lenses for correction of myopia

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.

Evaluation of Visual Outcome of 2 Phakic Posterior Chamber Implantable Lenses in High Myopia: A Comparative Study

PURPOSE

To evaluate and compare the visual outcomes of two phakic intraocular lenses in high myopia.

METHODS

A prospective comparative study was undertaken on 50 eyes of 26 patients {age ≥21 years and divided into two groups (implantable collamer lens [ICL] V4c, n=25 eyes and refractive implantable lens [RIL], n=25 eyes)}. Patients were evaluated for uncorrected distance visual acuity (UCVA), best-corrected distance visual acuity, manifest refractive spherical equivalent (MRSE), contrast sensitivity, intraocular pressure, dilated fundus examination, trabecular-iris angle (TIA), anterior chamber depth, horizontal white-to-white diameter, wavefront aberrometry, and endothelial cell (EC) count. All patients were followed up until 6 months and additionally evaluated for anterior chamber inflammation, cataract, and lens vault.

RESULTS

The baseline parameters (UCVA, MRSE, and EC count) and postoperative improvement in UCVA, contrast sensitivity, MRSE, EC loss, safety index, and efficacy index were comparable between both the lenses. The improvement in aberrometric profile was significantly better in the ICL group. The mean postoperative vault was higher in RIL group (434.88±162.48 μm vs. 547.24±159.83 μm, P=0.0173); however, the vault was within normal range in both the groups. The decrease in mean TIA was significantly higher in RIL group (8.58 vs. 13.45 μm, P=0.0073).

CONCLUSION

Acrylic phakic lens can be considered as a suitable alternative to collamer lens for refractive correction of high myopia. The collamer lenses showed slight superiority in some qualitative visual parameters; however, collamer lenses do not present with subjective complaints in the patients.

Visual and Refractive Outcomes With the Eyecryl Phakic Toric IOL Versus the Visian Toric Implantable Collamer Lens: Results of a 2-Year Prospective Comparative Study

PURPOSE

To compare the 2-year visual and refractive outcomes with the Eyecryl Phakic Toric IOL (EP TIOL) (Biotech Vision Care Pvt Ltd) and Visian Toric ICL (TICL) (STAAR Surgical) for correction of high myopic astigmatism.

METHODS

This prospective, interventional, non-randomized comparison study included eligible patients who underwent toric phakic IOL surgery in one or both eyes with either the EP TIOL or TICL for myopic astigmatism. Two years postoperatively, both lenses were compared for their safety, efficacy, stability, and patient satisfaction. Vector analysis of astigmatism was performed using the Alpins method with the ASSORT software (ASSORT Party Ltd).

RESULTS

A total of 50 eyes were included, of which 25 eyes received EP TIOL implantation and the remaining 25 received TICL implantation. Preoperative mean ± standard deviation of spherical equivalent (SE) and cylinder was -10.15 ± 4.04 and -2.08 ± 0.86 diopters (D) in the EP TIOL group and -10.21 ± 3.97 and -2.17 ± 0.95 D in the TICL group, respectively. At 2 years of follow-up, there was no significant difference between the mean uncorrected distance visual acuity, corrected distance visual acuity, spherical equivalent, and residual astigmatism between the two groups (P > .05 for all parameters). Ninety-two percent of eyes in the EP TIOL group and 88% of eyes in the TICL group were within ±0.50 D of refractive astigmatism. Vector analysis of astigmatism showed a comparable Correction Index of 0.98 in the EP TIOL group and 0.94 in the TICL group, signifying a mild undercorrection of 2% and 6%, respectively. Two eyes in the TICL group underwent exchange for high vault and one eye required realignment due to significant postoperative rotation.

CONCLUSIONS

At least for the first 2 years postoperatively, both toric phakic IOLs were safe and effective in managing high myopic astigmatism with comparable visual results and patient satisfaction. [J Refract Surg. 2021;37(1):7-15.].

Long-term efficacy and safety results after iris-fixated foldable phakic intraocular lens for myopia and astigmatism: 6-year follow-up

PURPOSE

To evaluate the long-term efficacy and safety of iris-fixated foldable phakic intraocular lenses (pIOLs) for the management of myopia and astigmatism after 6-year follow-up.

SETTING

Ophthalmology Department, Hospital Braga, Portugal.

DESIGN

Retrospective cohort study.

METHODS

Patients included underwent iris-fixated foldable Artiflex pIOL implantation between January 2010 and December 2013. Follow-up evaluations were performed 6 months postoperatively and every 12 months until 72 months. Preoperative and follow-up data on uncorrected and corrected distance visual acuity (CDVA), manifest refraction, endothelial cell density (ECD), and anterior chamber depth (ACD) were analyzed.

RESULTS

A total of 177 eyes of 98 patients with a mean age of 32.33 ± 7.13 years were analyzed. There was a statistically significant improvement in CDVA from 0.09 ± 0.02 logMAR preoperatively to 0.04 ± 0.02 logMAR (P < .0001) at 6 years postoperatively. The spherical equivalent demonstrated a statistically significant improvement from -9.50 ± 2.93 diopters (D) to -0.41 ± 0.45 D at 6 years. At 72 months, the efficacy and safety indexes were 0.94 and 1.15, respectively. A mean loss of 31.77 cells/mm2 (1.19%) was observed each year until the sixth year. The overall mean ECD loss after correction for the physiological loss was 3.02% after 6 years. No correlations were observed between the mean ECD loss and the preoperative ACD.

CONCLUSIONS

The Artiflex pIOL was a safe, effective, and a stable option to correct myopia. A mean ECD loss of 3.02% was observed over 6 years. No pIOL was explanted due to corneal decompensation.

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.

Bilateral Toric Phakic Intraocular Lens Implantation for Correction of High Myopic Astigmatism in a Patient with Marfan Syndrome with Lens Coloboma: A Case Report

Marfan syndrome (MFS) is known to cause significant refractive error. Treatment options are limited in this condition for correcting refractive error. Clear lens exchange is done in these cases, but complication rates are high. Loss of accommodation is another concern in these young adults. We report toric phakic intraocular lens (pIOL) implantation in improving the uncorrected visual acuity (UCVA) in a known case of MFS with lens coloboma. A 22-year-old female patient with MFS with inferior lens coloboma underwent bilateral toric pIOL implantation in the same sitting. Pre- and post-operative UCVA and best-corrected visual acuity were assessed. Central and peripheral vaulting of the pIOL in relation to the natural lens was also assessed. UCVA improved from 20/500 to 20/20 in the right and 20/550–20/20 in the left eye. Marked central vaulting with partial peripheral vaulting was achieved. There were no post-operative complications. Phakic IOL implantation surgery could be an effective approach to achieve excellent uncorrected refractive outcome in patients with MFS to treat high myopia.

Artisan versus Artiflex phakic intraocular lens implantation in the treatment of moderate to high myopia: meta-analysis

Background

To compare the postoperative safety, efficacy, predictability, visual quality and biomechanics after implantation of Artisan vs. Artiflex phakic intraocular lenses (PIOLs).

Methods

Pubmed, Embase, Cochrane Library were conducted up from January 2000 to February 2020. Comparative clinical studies reporting in accordance with the eligibility criteria were included in this meta-analysis. The pooled weighted mean differences (WMDs) and odds ratios (ORs) with corresponding 95% confidence intervals were calculated.

Results

Comparative trials with myopia patients were selected in this review. The pooled WMD and OR estimates statistical significance in terms of postoperative best corrected visual acuity (BCVA), efficacy, postoperative spherical equivalence (SE), predictability, contrast sensitivity and mean intraocular higher-order aberrations (HOA) (mm) for a 6-mm pupil, manifesting that Artiflex PIOL showed evident beneficial effect for correcting myopia compared to Artisan PIOL. There was no significant difference in the incidence of complications between the two groups.

Conclusion

Both of two techniques were safe and effective for myopia and compared to Artisan PIOL, Artiflex PIOL had significant improvement in efficacy, predictability, contrast sensitivityand HOA, except safety and complications in the treatment of moderate to high myopia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12886-021-01930-6.

Comparative Analysis of Morphological and Release Profiles in Ocular Implants of Acetazolamide Prepared by Electrospinning

The visual impairment that often leads to blindness causes a higher morbidity rate. The goal of this work is to create a novel biodegradable polymeric implant obtained from coaxial fibers containing the dispersed drug-acetazolamide-in order to achieve sustained drug release and increase patient compliance, which is of the highest importance. Firstly, during this work, uncoated implants were produced by electrospinning, and rolled in the shape of small cylinders that were composed of uniaxial and coaxial fibers with immobilized drug inside. The fibers were composed by PCL (poly ε-caprolactone) and Lutrol F127 (poly (oxyethylene-b-oxypropylene-b-oxyethylene)). The prepared implants exhibited a fast rate of drug release, which led to the preparation of new implants incorporating the same formulation but with an additional coating film prepared by solvent casting and comprising PCL and Lutrol F127 or PCL and Luwax EVA 3 ((poly (ethylene-co-vinyl acetate)). Implants were characterized and in vitro release profiles of acetazolamide were obtained in phosphate buffered saline (PBS) at 37 °C. The release profile of the acetazolamide from coated implant containing Luwax EVA 3 is considerably slower than what was observed in case of coated implants containing Lutrol F127, allowing a sustained release and an innovation relatively to other ocular drug delivery systems.

Visian® ICLV4c™ and Artiflex®: Comparative Analysis with the HD AnalyserTM and Integration with Subjective Performance and Anatomical Parameters

Purpose

To analyze and compare the mid-term objective and subjective performance of two phakic intraocular lenses (PIOLs) – Visian^® ICL™ V4c and Artiflex^® and to correlate those results with anatomical parameters.

Patients and Methods

Observational retrospective study including thirty patients (15 for each PIOL) randomly selected from those who underwent bilateral implantation of one of the PIOLs (60 eyes were analysed). Uncorrected and corrected distance visual acuities (UDVA and CDVA), anterior chamber structural parameters, and corneal endothelial cells density and morphology were evaluated. Quality of vision was assessed both subjectively with a questionnaire, and objectively using a double-pass technology optical quality analysis system.

Results

At the end of follow-up the Artiflex^® group showed better UDVA (0.95±0.11 vs 0.99±0.05, p=0.027) and higher proportion of eyes reaching at least 20/20 (28/30 vs 18/30, p=0.005). Excellent and similar objective scatter index (1.79±0.9 vs 2.14±1.6, p=0.306) and modular transfer function cutoff frequency (26.91±9.2 vs 26.51±11.9, p=0.784) results were achieved in the HD Analyzer^® and the questionnaire showed comparable high Satisfaction (55.7±3.5 vs 54.3±5.4, p=0.386) and low Dysphotopsia Scores (3.1±1.8 vs 2.1±2.2, p=0.213). The ICL group showed inferior anterior chamber volume (p<0.001), and angle (p<0.001) and superior pupillary diameter (p=0.007). Minimum follow-up was 24 months.

Conclusion

Both the Visian^® ICLV4c™ and the Artiflex^® showed excellent optical performance through the HD Analyzer^TM technology, translated in high patient satisfaction. Overall, both PIOLs showed similar safety, predictability, stability and effectiveness of for the reduction of high sphero-cylindrical refractive errors, despite better UDVA results with the Artiflex^®.

Three-Year Effect of Phakic Intraocular Lenses on the Corneal Endothelial Cell Density

Purpose

To compare the effect of three different phakic intraocular lenses (pIOLs) on the corneal endothelial cell density (ECD).

Patients and Methods

This was a prospective observational cohort study that included 60 eyes (30 patients) with axial myopia of −6.50 to −22.00 diopters (D). The Verisyse anterior chamber (AC) rigid iris fixated pIOL, the Veriflex (AC) flexible iris fixated pIOL, and the Visian posterior chamber (PC) implantable collamer lens (ICL) were implanted in three equal groups of patients. The effect of the three pIOLs on the ECD was compared over a follow-up period of one week, and one, three, and six months, and one, two, and three years. Specular microscopy was done to evaluate the cornea before the surgery and throughout the study. Changes were statistically analyzed and compared.

Results

In the first three postoperative months, Verisyse and Veriflex pIOLs induced almost the same amount of endothelial cells loss of 10.3% and 10.6%, respectively, while ICLs showed endothelial cells loss of 3.5%. At the end of the three-year study, Veriflex pIOLs induced the highest rate of endothelial cell loss of 25%, while Verisyse and ICL lenses showed endothelial cells loss of 15.7% and 13.4%, respectively. The main effect of time and type of lens was statistically significant (p<0.001).

Conclusion

All pIOLs cause a decrease in ECD. The AC pIOLs tend to be associated with more cell loss than PC pIOLs. Surgical insult is the important factor responsible for the early endothelial cell loss, while the material from which the pIOL is made may be an important factor for the continuous corneal endothelial cell loss over a long time.

Comparison of rigid versus foldable iris-fixed phakic intraocular lens implantation for high myopia: A systematic review and meta-analysis

BACKGROUND

This study aimed to assess the efficacy of rigid versus foldable iris-fixed phakic intraocular lens (PIOL) implantation in the treatment of high myopia.

METHODS

A systematic search based on electronic databases such as Pubmed, Embase, and Cochrane Library was conducted to identify relevant studies published up to January 11, 2019. The pooled odds ratios and weighted mean differences (WMDs) with corresponding 95% confidence intervals were calculated.

RESULTS

Eight comparative studies with 835 participants were included in this meta-analysis. The overall WMD showed statistical significance in terms of postoperative uncorrected distance visual acuity (UDVA), mean postoperative spherical equivalence (SE), and mean postoperative intraocular higher-order aberrations (HOA) (μm) for a 6-mm pupil, suggesting that foldable PIOL group showed significant improvement of high myopia, compared to rigid PIOL group. Besides, compared with rigid PIOL group, foldable PIOL group had beneficial effect on the proportion of eyes with central endothelial cell density (ECD) loss in patients with high myopia.

CONCLUSION

This meta-analysis provided the up-to-date evidence and found that foldable PIOL group had significant beneficial effect on UDVA, SE, HOA, contrast sensitivity, and ECD, except best spectacle-corrected visual acuity, and safety in the treatment of high myopia over rigid PIOL group.

Comparative Study of Implantable Collamer Lens Implantation in Treating Four Degrees of Myopia: Six-Month Observation of Visual Results, Higher-Order Aberrations, and Amplitude of Accommodation

PURPOSE

To compare the visual and refractive outcomes, higher-order aberrations (HOAs), and amplitude of accommodation (AA) after implantable collamer lens (ICL) model V4c implantation in four degrees of myopia.

METHODS

One hundred and thirty-seven myopic eyes (137 patients) undergoing ICL implantation were included and divided into four groups: Group 1 with spherical equivalent (SE) ≤-6.0D, Group 2 with SE from -6.13D to -9.0D, Group 3 with SE from -9.13D to -12.0D, and Group 4 with SE from -12.13D to -18.0D. The postoperative visits were scheduled at 1 day, 1 week, 1 month, 3 months, and 6 months. Visual and refractive outcomes, HOAs and AA were observed and compared.

RESULTS

At 6 months postoperatively, the uncorrected distance visual acuity (UDVA) in Group 4 was worse than the values in the other groups (all p < .05). Meanwhile, Group 4 had more eyes with corrected distance visual acuity (CDVA) improvement than the other groups. Furthermore, 96%, 100%, 100%, and 81% of eyes had an SE within ±0.5D in Group 1, Group 2, Group 3, and Group 4 (p < .05 between Group 4 and the other groups), respectively. The postoperative UDVA and SE remained stable in all groups. No significant change in total HOAs was found between preoperative and postoperative values for each group. However, quatrefoil increased in each group, whereas trefoil was induced in all groups except for Group 1. Negative spherical aberration was induced in Group 3 and Group 4. AA significantly decreased 1 week postoperatively and gradually improved in each group. Although AA improved to the preoperative level in Group 1 at 3 months postoperatively, it was still lower than the preoperative level in the other groups.

CONCLUSIONS

In treating different degrees of myopia with ICL implantation, differences were observed in terms of CDVA improvement, SE predictability, HOAs induction, and accommodation recovery.

Off-Label Use of Phakic Intraocular Lens with a "Piggyback" Technique

Purpose

We report a case of a highly myopic pseudophakic patient who received off-label placement of a phakic intraocular lens (pIOL) via a “piggyback” technique, allowing the placement of an intraocular lens (IOL) in his fellow eye, resulting in improved visual acuity and emmetropia.

Case Report

A 66-year-old, highly myopic, pseudophakic male with an IOL implant in his left eye was referred for second opinion for surgical options for his phakic right eye. Given the severe myopic status of both eyes, he received off-label placement of a posterior chamber pIOL with a piggyback technique for the pseudophakic left eye followed by standard cataract surgery and intraocular lens implantation in the right eye. For the left eye, uncorrected best visual acuity improved from 20/70 to 20/25.

Conclusion

This case demonstrates the successful off-label use of a phakic IOL in a pseudophakic, highly myopic patient with a piggyback technique, resulting in improved visual acuity and ultimately allowing IOL placement in the fellow eye for emmetropia. This off-label use of pIOL can offer ophthalmologists an alternative option for pseudophakic patents with severe refractive error.

Wavefront aberration and contrast sensitivity after implantation of foldable and rigid iris claw phakic intraocular lenses: Artiflex versus artisan

Aim of study:

The aim of this study is to assess wavefront aberration and contrast sensitivity (CS) after implantation of foldable iris claw – artiflex- and rigid iris claw – artisan- phakic intraocular lenses (pIOLs).

Materials and Methods:

A nonrandomized prospective comparative case study was performed on 57 eyes; of which, 54 were myopia and 3 were hyperopia. Twenty-four patients had artisan pIOL implantation and 33 had artiflex pIOL implantation. Higher-order aberration (HOA) and CS were obtained 1 year after surgery.

Results:

Total HOA in artisan group was greater than artiflex group (P = 0.044) with a mean HOA of 0.44 ± 0.15 root mean square (RMS) for artisan and 0.35 ± 0.15 RMS for artiflex. Although, there were no significant differences in the vertical trefoil, vertical coma, horizontal trefoil, horizontal coma, secondary astigmatism, quatrefoil, and fourth order spherical aberration in two groups. CS in mesopic conditions was better in artiflex-treated eyes at three spatial frequencies of 6, 12, and 18 cycles per degree (cpd) (P = 0.003, P = 0.007, and P = 0.00, respectively), and no significant difference was seen between two lenses at 3 cpd.

Conclusion:

Although the components of HOA were not significantly different between two groups, total HOA was higher in artisan group, which may be due to the slight differences in each component, increasing the HOA as a total. CS was significantly better in artiflex group.