Trifocality Achieved Through Polypseudophakia: Optical Quality and Light Loss Compared With a Single Trifocal Intraocular Lens

Polypseudophakia: from "Piggyback" to supplementary sulcus-fixated IOLs

Polypseudophakia, the concept of using a second intraocular lens (IOL) to supplement an IOL that has already been placed in the capsular bag, was first used as a corrective measure where the power requirement was higher than that of available single IOLs. Subsequently, the technique was modified to compensate for post-operative residual refractive errors. In these early cases, an IOL designed for the capsular bag would be implanted in the sulcus.  Although these approaches were less than ideal, alternative means of correcting residual refractive errors were not without their limitations: IOL exchange can be traumatic to the eye and is not easily carried out once fibrosis has occurred, while corneal refractive surgical techniques are not suitable for all patients. Piggyback implantation was the term first coined to describe the use of two IOLs, placed together in the capsular bag. The term was later extended to include the procedure where an IOL designed for the capsular bag was placed in the sulcus. Unfortunately, the term piggyback has persisted even though these two approaches have been largely discredited. Intraocular lenses are now available which have been specifically designed for placement in the ciliary sulcus. As these newer IOLs avoid the many unacceptable complications brought about by both types of earlier piggyback implantation, it is time to employ a new terminology, such as supplementary IOL or secondary enhancement to distinguish between the placement of an unsuitable capsular bag IOL in the sulcus and the implantation of an IOL specifically designed for ciliary sulcus implantation. In addition to minimising possible complications, supplementary IOLs designed for the sulcus have expanded the options available to the ophthalmic surgeon. With these new IOLs it is possible to correct presbyopia and residual astigmatism, and to provide temporary correction of refractive errors in growing, or unstable, eyes. This article aims to review the literature available on supplementary IOL implantation in the ciliary sulcus and to summarise the evidence for the efficacy and safety of this intervention. KEY MESSAGES: What is known Polypseudophakia has been used for over 30 years to correct hyperopia or residual refractive error, but early techniques were associated with significant complications. What is new The development of specially designed sulcus-fixated supplementary IOLs significantly reduces the risks associated with these procedures, and has also opened up new opportunities in patient care. The reversibility of the procedure allows patients to experience multifocality, and to provide temporary and adjustable correction in unstable or growing eyes. The terms "secondary enhancement" or "DUET" to describe supplementary IOL implantation are preferential to "piggyback".

[Complex optical systems for individualized correction of presbyopia]

A multitude of available intraocular lens (IOL) models enable a personalized approach to presbyopia correction in order to meet each patient's needs. This review article discusses more complex approaches which can be useful in selected cases. The concept of reversible trifocality enables correction of presbyopia using a supplementary intraocular lens (IOL), which can be removed if necessary (e.g., intolerance to multifocal optics). The use of capsulotomy-fixated IOLs enables high precision for positioning of the lens and better stability compared to conventional capsular bag-fixated IOLs, which can be particularly advantageous in multifocal optics. The mix and match concept enables a combination of different IOLs with various optical principles to achieve the desired binocular effect. Binocular IOL systems, which consist of two complementary IOLs, can be seen as a further development of the mix and match concept. Knowledge of the available options and their application can further improve correction of presbyopia.

Effect of decentration and tilt on the in vitro optical quality of monofocal and trifocal intraocular lenses

PURPOSE

To evaluate and compare the effect of decentration and tilt on the optical quality of monofocal and trifocal intraocular lenses (IOL).

METHODS

Optical quality of a monofocal IOL (AcrySof IQ SN60WF; Alcon Laboratories, Inc., USA) and a trifocal IOL (AcrySof IQ PanOptix; Alcon Laboratories, Inc., USA) was assessed using an in vitro optical bench (OptiSpheric IOL R&D; Trioptics GmbH, Germany). At apertures of 3.0 mm and 4.5 mm, modulation transfer function (MTF) at spatial frequency of 50 lp/mm, MTF curve and the United States Air Force (USAF) resolution test chart of the two IOLs were measured and compared at their focus with different degrees of decentration and tilt. Optical quality at infinity, 60 cm and 40 cm and the through-focus MTF curves were compared when the two IOLs were centered at apertures of 3.0 mm and 4.5 mm. Spectral transmittance of the two IOLs was measured by the UV-visible spectrophotometer (UV 3300 PC; MAPADA, China).

RESULTS

The SN60WF and the PanOptix filtered blue light from 400 to 500 nm. Both IOLs at the far focus and the PanOptix at the intermediate focus showed a decrease in optical quality with increasing decentration and tilt. The PanOptix demonstrated enhanced optical quality compared to the previous gradient at the near focus at a decentration range of 0.3-0.7 mm with a 3.0 mm aperture, and 0.5 mm with a 4.5 mm aperture, whereas other conditions exhibited diminished optical quality with increasing decentration and tilt at the focus of both IOLs. When the two IOLs were centered, the SN60WF had better optical quality at infinity, while the PanOptix had better optical quality at 60 cm and 40 cm defocus. The optical quality of the SN60WF exceeded that of the PanOptix at far focus, with a 3 mm aperture decentration up to 0.7 mm and a 4.5 mm aperture decentration up to 0.3 mm; this observation held true for all tilts, irrespective of aperture size. As both decentration and tilt increased, the optical quality of the SN60WF deteriorated more rapidly than that of the PanOptix at the far focal point.

CONCLUSIONS

The SN60WF showed a decrease in optical quality with increasing decentration and tilt. Optical quality of the PanOptix at the near focus increased in some decentration conditions and decreased in some conditions, while it showed a decrease at the other focuses with increasing decentration. While tilt only had a negative effect on optical quality. When both IOLs were centered, the PanOptix provided a wider range of vision, while the SN60WF provided better far distance vision. At the far focus, the SN60WF has better resistance to tilt than the PanOptix, but the optical quality degrades more quickly when decentered and tilted.

Rotational Stability of Toric Capsular Bag-Fixated Intraocular Lenses in Duet Procedure for Reversible Trifocality

PURPOSE

To evaluate the long-term rotational stability of capsular bag-fixated toric intraocular lenses (IOLs) in polypseudophakic eyes of patients who underwent duet procedure for reversible trifocality.

DESIGN

Retrospective interventional case series.

METHODS

We included 34 eyes of 20 patients who underwent duet procedure with implantation of a monofocal toric IOL (RayOne toric, Hoya XY1AT, or a Tecnis ZCT800) into the capsular bag and a trifocal-diffractive Sulcoflex IOL into the ciliary sulcus. All toric IOLs were implanted with image-guided navigation. The manifest refraction and uncorrected and distance corrected visual acuity at far, intermediate, and near distance were measured. The position of the axis of the toric IOL was determined with the Pentacam device (Oculus GmbH) by evaluating retroillumination images. The results were compared with the preoperatively planned axis position.

RESULTS

The median follow-up was 27 months. The spherical equivalent of manifest refraction was -0.04 ± 0.34 diopters (D) postoperatively, and the refractive cylinder was -0.14 ± 0.22 D on average. Binocular uncorrected and corrected distance visual acuity were 0.05 ± 0.11 logMAR and 0.02 ± 0.09 logMAR, respectively. The mean deviation from the calculated cylinder axis was 3.8° ± 3.5° with a median of 2.8° and a maximum deviation of 15.0°. Ninety-four percent of all eyes showed a deviation of less than 10°.

CONCLUSIONS

The long-term axial alignment of capsular bag-fixated toric IOLs in polypseudophakic eyes was comparable to the results reported for single implantation of toric IOLs. The polypseudophakic approach did not affect the rotational stability of capsular bag-fixated IOLs.

Reversible Multifocality Achieved Through Polypseudophakia

Simultaneous implantation of a monofocal or monofocal toric intraocular lens (IOL) into the capsular bag and a multifocal IOL into the ciliary sulcus, referred to as duet procedure, allows us to create multifocality that is more easily reversible than the implantation of a capsular bag-fixated multifocal IOL. The optical quality and results after the duet procedure are equivalent to those of a capsular bag-fixated multifocal IOL. Patients who cannot tolerate the side effects of multifocal optics or who develop an ocular condition leading to loss of function such as age-related macular degeneration (AMD) or glaucoma in the course of their lives may benefit from the reversibility of the procedure.

Comparison of a Presbyopia-Correcting Supplementary Intraocular Lens Combination and a Capsular-Bag Lens: An In Vitro Study

We evaluated the optical quality of two approaches to trifocality: polypseudophakia versus monopseudophakia. The combination (polypseudophakia) of a monofocal Basis Z B1AWY0 and AddOn Trifocal A4DW0M intraocular lens (IOL) was compared to using one Basis Z Trifocal B1EWYN IOL, all from 1stQ GmbH. In both approaches, we measured modulation transfer function (MTF) and Strehl Ratio (SR) values at 3.0 and 4.5 mm pupil sizes. We determined the through-focus (TF) MTF at 25, 50 and 100 lp/mm for the 3 mm aperture. United States Air Force (USAF) target images were recorded. MTF measurement of the trifocal lens and the combined monofocal and trifocal AddOn IOL showed good performance at the far and near focus for the 3 mm aperture. For the 4.5 mm aperture the MTF improved for the far focus but decreased for the intermediate and near focus. TF MTF showed better contrast at the far focus for the polypseudophakic setup but at the expense of the efficiency at the near focus. However, the USAF chart images revealed only minimal differences between both approaches. The optical quality of the polypseudophakic approach was not affected by the presence of two IOLs instead of one and proved to be comparable with the performance of one capsular-bag-fixated trifocal IOL. Differences between the single vs. two-lens approach seen in the TF MTF analysis could be attributed to the optical design that varied between the trifocal models.

Comparison of Five Presbyopia-Correcting Intraocular Lenses: Optical-Bench Assessment with Visual-Quality Simulation

Presbyopia correction through implantation of a trifocal intraocular lens (IOL) is a modality offered to both cataract and refractive-lens exchange patients. To maximize postoperative satisfaction, IOL selection needs to be made based on patients’ requirements aligned with the available technology. Five Trifocal IOLs were assessed in this study, and their differentiating features were identified: Triumf POD L GF, AT Lisa Tri, Tecnis Synergy, AcrySof IQ PanOptix, and Acriva Trinova Pro C. The optical quality was assessed using the modulation-transfer-function principle. Simulated defocus curves were derived from a non-linear formula. Far-focus simulated visual acuity (simVA) was 0.03 logMAR or better for all the studied IOLs, showing minimal differences. However, each IOL’s intermediate focus position differed across a range from 61 cm to 80 cm; and for the near focus, it was 36 cm to 44 cm. Triumf demonstrated improved intermediate point at the expense of the near focus resulting in a lower predicted near VA. PanOptix exhibited the shortest range of vision without a clear distinction between intermediate and near-point. The remaining lenses presented three foci of comparable optical quality and, thus, simVA performance. Each model, however, revealed a different aperture-change response. Trinova function improved at intermediate but was worse at near for larger pupils. The opposite was observed for AT Lisa. Synergy’s optical quality change was predominantly associated with lower pupil diameter. In conclusion, the trifocal IOLs can be differentiated according to their secondary-foci position, light-energy distribution, and pupil-size-related behavior. The observed differences may translate directly into a clinical effect showing that the trifocal IOLs vary in their ability to deliver optimal vision at different distances, with some providing improved intermediate while others favor reading distance. The knowledge gained through this objective testing can support IOL selection, postoperative patient counselling and increase the chance of spectacle independence after surgery.

Comparison of Primary Duet Lens Procedures: In-The-Bag Monofocal with Sulcus Multifocal, and Standard Single Multifocal Lens for Cataract Surgery

Purpose

To assess the safety and efficacy of primary duet intraocular lens (IOL) procedure using an in-The-bag monofocal IOL and a sulcus-based multifocal reversible platform for cataract surgery. The visual outcomes were compared with a single in-The-bag multifocal IOL.

Patients and Methods

Retrospective cohort study. Consecutive patients who underwent primary duet IOL procedures were compared with consecutive patients who underwent single multifocal IOL surgery. Primary outcomes were uncorrected distance and near visual acuities (UDVA and UNVA), refraction and spherical equivalent data. Secondary outcomes included surgical complications.

Results

The study group consisted of 32 eyes (22 toric IOLs) whilst the control group had 57 eyes (29 toric IOLs). There were no statistically significant differences between the two groups on post-operative 1-month and 1-year UDVA (p=0.1522 and 0.4926, respectively) and UNVA (p=0.1248 and 0.2738, respectively). There were no statistically significant differences in the postoperative 1-month spherical equivalent within ± 0.5 diopter (p=0.1891). Postoperative intraocular pressure spikes were observed on day-1 in both groups, with most returned to their baseline at 1-month and all were normal at 1-year post surgery. There were no statistically significant differences in intraocular pressure between the two groups on day-1, 1-month and 1-year after surgery (p=0.6421). There were no statistically significant differences in the IOL axis deviation from the intended axis in the toric subgroup analysis (p=0.5843).

Conclusion

Primary duet IOL procedure is equally effective and safe in correcting distance and near vision when compared with single multifocal IOL in the capsular bag.

Visual performance and impact of residual refractive errors with trifocal intraocular lenses of different aspheric design

BACKGROUND

To assess the visual quality and the tolerance to low refractive errors of two trifocal intraocular lenses (IOL) with different amounts of spherical aberration (SA).

METHODS

The study included patients having bilateral implantation of the AcrySof® IQ PanOptixTM (aberration-correcting) or the RayOneTM (aberration-free) Trifocal IOL. Three months after the surgery patients underwent: monocular/binocular and uncorrected/corrected distance visual acuity (VA) and binocular defocus curves. Binocular contrast sensitivity (CSF) and subjective halo perception were assessed with the best distance correction (CDVA), with a positive defocus of + 0.50D and with a negative defocus of -0.50D. Patient's satisfaction was evaluated with the Catquest9-SF questionnaire.

RESULTS

This study included 54 eyes (28 with PanOptix and 26 with RayOne) of 27 patients. Both groups achieved corrected/uncorrected and monocular/binocular distance VA values better than 0.0 logMAR (1.0 decimal) with no statistically significant differences between them (p > 0.05 for all cases). Defocus curves showed a VA of 0.1 logMAR or better between -2.5 and + 1.0D with no differences between groups (p > 0.05 at all distances). Overall CSF values remained stable under the induced residual refractions for both groups. The halo effect remained stable for the PanOptix group but increased with myopization in the RayOne group (p = 0.02). The questionnaire showed high rates of patient's satisfaction with no differences between groups.

CONCLUSION

Both lenses showed overall good visual outcomes and offered high rates of patient's satisfaction. Moreover, in normal patients with trifocal IOLs, the combination of residual refractive errors and certain amounts of SA may increase some visual disturbances.

Light scattering from a diffractive-refractive intraocular lens: a goniometer-based approach for individual zone assessment

We proposed and tested a method to measure light scattering from the diffractive lens profile in an echelle element featuring 9 zones. Measurements were performed using a goniometer-based setup up to 7.5°. The proportion of scattered light was calculated to derive the loss of light. Material scattering was minimal (∼1 deg2/sr); however, each echelle zone acted as a scattering source. A nearly gradual straylight increase was found with the zone number showing peak intensity between 3° and 3.75°. An estimated 6.2% ± 0.1% was lost due to scattering, which ought to be considered when reporting an IOL's light loss.

Clinical outcomes in patients after duet procedure for reversible trifocality using a supplementary trifocal IOL

PURPOSE

We report the clinical outcomes of patients who had primary lens implantation in the capsular bag and subsequently a supplementary trifocal lens implanted in the ciliary sulcus (duet procedure) to create reversible trifocality.

DESIGN

Retrospective interventional case series.

METHODS

Twenty-five patients were included in this single center clinical study, who had undergone either refractive lens exchange for presbyopia correction or cataract surgery. All had lens removal by phacoemulsification and duet procedure to achieve reversible trifocality. Preoperatively and three months postoperatively, uncorrected (UDVA) and corrected distance visual acuity (CDVA) were assessed, as well as uncorrected (UNVA), distance corrected (DCNVA) and corrected near visual acuity (CNVA). At the postoperative examination, uncorrected (UIVA), distance corrected (DCIVA) and corrected intermediate visual acuity (CIVA), defocus curve testing and dysphotopsia evaluation were also performed.

RESULTS

Monocular UDVA and CDVA improved from 0.71 ± 0.43 logMAR and 0.12 ± 0.16 logMAR preoperatively to 0.04 ± 0.10 logMAR and -0.01 ± 0.09 logMAR postoperatively. Monocular UNVA and DCNVA were both 0.06 ± 0.08 logMAR and UIVA and DCIVA 0.00 ± 0.10 logMAR and -0.02 ± 0.10 logMAR postoperatively. Monocular defocus curve testing revealed a visual acuity of 0.2 logMAR or better from +0.75 to -3.5 diopters.

CONCLUSIONS

Duet procedure using a trifocal supplementary IOL provided excellent results for far, near and intermediate distance, comparable to those reported for capsular bag fixated trifocal IOLs. The duet procedure offers the advantage of an exit-strategy in cases with a future loss of function or side effects associated with the optics.

Refractive Outcomes after Cataract Surgery

A post-operative manifest refractive error as close as possible to target is key when performing cataract surgery with intraocular lens (IOL) implantation, given that residual astigmatism and refractive errors negatively impact patients’ vision and satisfaction. This review explores refractive outcomes prior to modern biometry; advances in biometry and its impact on patients’ vision and refractive outcomes after cataract surgery; key factors that affect prediction accuracy; and residual refractive errors and the impact on visual outcomes. There are numerous pre-, intra-, and post-operative factors that can influence refractive outcomes after cataract surgery, leaving surgeons with a small “error budget” (i.e., the source and sum of all influencing factors). To mitigate these factors, precise measurement and correct application of ocular biometric data are required. With advances in optical biometry, prediction of patient post-operative refractory status has become more accurate, leading to an increased proportion of patients achieving their target refraction. Alongside improvements in biometry, advancements in microsurgical techniques, new IOL technologies, and enhancements to IOL power calculations have also positively impacted patients’ refractory status after cataract surgery.

Systematic Review of the Use of Supplemental Multifocal Intraocular Lenses in the Ciliary Sulcus for Presbyopia Correction

PURPOSE

To conduct a critical review of the peer-reviewed literature on the use of supplemental multifocal intraocular lenses in the ciliary sulcus.

METHODS

This systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement recommendations. According to the inclusion and exclusion criteria defined, 15 articles were selected for the current systematic review. Each of them was analyzed carefully and their risk of bias was assessed with the Quality Assessment Tool for Case Series Studies from the National Heart, Lung, and Blood Institute.

RESULTS

Data of 384 eyes from 227 patients were analyzed. Most of the studies reviewed had a short follow-up and poor or limited design, including case reports, case series, and clinical trials with several gaps in their methodology. Post-operative uncorrected distance and near visual acuity ranged from 20/40 to 20/20 and from 0.4 to 0.02 logMAR, respectively. Pigment dispersion (12 eyes) and deposits (13 eyes) were the most described complication. Dysphotopsia, glare, and halos were the more frequently reported visual disturbances. However, most of the patients reported a high level of satisfaction with their surgery. Most articles reviewed (13 of 15) achieved a risk of bias score between 6 and 8, representing a high level of evidence despite the study design limitations.

CONCLUSIONS

Supplemental multifocal intraocular lenses seem to offer good distance and near visual results, leading to high levels of spectacle independence and patients' satisfaction, with limited complications associated. However, more studies with a more robust design are needed to confirm these trends. [J Refract Surg. 2021;37(12):830-835.].

Simulations of Decentration and Tilt of a Supplementary Sulcus-Fixated Intraocular Lens in a Polypseudophakic Combination Using Ray-Tracing Software

This study aimed to assess image quality after the tilt and decentration of supplementary intraocular lenses (IOLs) in a two-lens configuration. One was designed for sulcus fixation with a nominal power range of 1D–10D and was combined with a capsular fixation 20D IOL. The optical performance of a ray-tracing model was tested under IOL misalignment through the area under the modulation transfer function (MTFa) and wave aberrations. Tilting by 10° resulted in a 4% reduction of the MTFa for a 10D IOL as compared to 9% for the 20D lens. The two models demonstrated good tolerance to a 1 mm decentration; as for the 10D sulcus-fixated lens, the MTFa loss was 2%, and 4% for the capsular fixation lens. Coma and astigmatism increased three- and four-fold, respectively, after a 10° tilt compared to the aberration level induced by the 1 mm decentration. Both analyses showed a trend towards a lower MTF impact and fewer optical errors with decreasing nominal power. In conclusion, when misaligned, low-power sulcus-fixated IOLs might retain their good optical quality. An extreme tilt of 10° has a more detrimental effect on the IOL performance than a 1 mm decentration. The proper alignment of a high-power capsular fixation lens is important in achieving a desirable postoperative outcome.

[Pupil reconstruction with an artificial iris]

BACKGROUND

Patients with iris defects suffer from severe visual impairment, especially increased glare sensitivity, and cosmetic disturbances. This can constitute a great psychological strain for patients. In the recent past the treatment consisted of iris print contact lenses, sunglasses and simple iris prostheses. The indications for surgical treatment are colobomas of the iris, aniridia, traumatic iris defects and persistent mydriasis. The aim of this review article is to investigate the surgical approaches, complications, functional and aesthetic outcome after implantation of an individual artificial iris prosthesis made from silicone.

OBJECTIVE

Analysis of the literature on the topic of surgical iris reconstruction with an artificial iris in combination with the own experience in more than 120 patients treated by the author in the last 10 years.

MATERIAL AND METHODS

The custom-made flexible silicone iris prosthesis ArtificialIris (HumanOptics, Erlangen, Germany) assessed in this review is an innovative and versatile option for surgical treatment of iris defects. Patients were examined before and after iris reconstruction with respect to feasibility, complications and outcome.

RESULTS

Change of best corrected visual acuity, intraocular pressure, pupillary opening, glare, contrast sensitivity, endothelial cell count, anterior chamber depth, anterior chamber angle and patient satisfaction were assessed. Furthermore, complications and color match to the residual and fellow iris were assessed.

CONCLUSION

The implantation of an artificial iris is an effective option for the treatment of extensive traumatic iris defects and leads to an individual aesthetically appealing and good functional outcome as well as high patient satisfaction; however, this is an intervention that should not be underestimated because of a flat learning curve and various complications that can occur.

Reversibility of the duet procedure: Bilateral exchange of a supplementary trifocal sulcus-fixated intraocular lens for correction of a postoperative refractive error

Purpose

We present the case of a 49-year old female who underwent bilateral exchange of a supplementary trifocal sulcus-fixated intraocular lens (IOL) to correct a residual refractive error. Six months beforehand, she had been treated for hyperopia, astigmatism and presbyopia with a duet procedure to create reversible trifocality.

Observations

Refractive lens exchange with combined implantation of a monofocal toric IOL into the capsular bag and a trifocal supplementary IOL into the ciliary sulcus (duet procedure) had been performed in both eyes. Decreased uncorrected distance visual acuity due to the refractive outcome of −0.75 diopter sphere (DS)/-0.25 diopter cylinder (DC)x10° for the right eye and −1.0DS for the left eye as well as the perception of photic phenomena were inacceptable for the patient. In the second operations, we exchanged the supplementary IOLs to correct the residual refractive error and achieve the target refraction of emmetropia. UDVA increased from 0.50 logMAR in both eyes prior to the IOL exchange to −0.22 logMAR in the right eye and −0.20 logMAR in the left eye. Binocular uncorrected near and intermediate visual acuity were −0.10 logMAR and 0.00 logMAR respectively after exchanging the sulcus-fixated supplementary IOLs, allowing for complete spectacle independence.

Conclusions

This case demonstrates one of the most important benefits of the duet procedure: the possibility, if necessary, to easily remove or exchange the supplementary IOL from the ciliary sulcus. The duet procedure offers a safe treatment option in the event of postoperative complications like residual refractive error or intolerance to a multifocal optic.