Benefits and barriers of accommodating intraocular lenses

BCLA CLEAR Presbyopia: Evaluation and diagnosis

It is important to be able to measure the range of clear focus in clinical practice to advise on presbyopia correction techniques and to optimise the correction power. Both subjective and objective techniques are necessary: subjective techniques (such as patient reported outcome questionnaires and defocus curves) assess the impact of presbyopia on a patient and how the combination of residual objective accommodation and their natural DoF work for them; objective techniques (such as autorefraction, corneal topography and lens imaging) allow the clinician to understand how well a technique is working optically and whether it is the right choice or how adjustments can be made to optimise performance. Techniques to assess visual performance and adverse effects must be carefully conducted to gain a reliable end-point, considering the target size, contrast and illumination. Objective techniques are generally more reliable, can help to explain unexpected subjective results and imaging can be a powerful communication tool with patients. A clear diagnosis, excluding factors such as binocular vision issues or digital eye strain that can also cause similar symptoms, is critical for the patient to understand and adapt to presbyopia. Some corrective options are more permanent, such as implanted inlays / intraocular lenses or laser refractive surgery, so the optics can be trialled with contact lenses in advance (including differences between the eyes) to better communicate with the patient how the optics will work for them so they can make an informed choice.

Comparison of bilateral implantation of an extended depth of focus lenses and a blend approach of extended depth of focus lenses and bifocal lenses in cataract patients

BACKGROUND

To compare the visual outcomes, spectacle independent rate and stereopsis in patients who underwent bilateral implantation of extended depth of focus (EDOF) intraocular lens (IOL), or a blend approach of EDOF and bifocal IOL.

METHODS

A total of 60 cataract patients, who were scheduled for phacoemulsification and intraocular lens implantation in both eyes in West China Hospital of Sichuan University, were enrolled and divided into Micro monovision group(-0.5D~-1.0D), Non-micro monovision group (< 0.5D) with Symfony IOL, and Mixed group with Symfony and ZMB00 IOLs. Three months postoperatively, we compared the visual acuity, modulation transfer function (MTF), defocus curve, stereopsis, spectacle independence, and photic phenomena among the three groups.

RESULTS

Compared to the Non-micro monovision group (UNVA: 0.07 ± 0.04), Micro monovision group (UNVA: 0.00 ± 0.07, P < 0.001) and Mixed group (UNVA: -0.02 ± 0.06, P < 0.001) showed improvement in binocular uncorrected near visual acuity (UNVA). Additionally, Mixed group exhibited lower MTF10 (MTF10: 0.38 ± 0.24) and point spread function (PSF: 0.192 ± 0.269) results in their non-dominant eye compared to both Micro monovision group (MTF10: 0.56 ± 0.21, P = 0.027; PSF: 0.417 ± 0.282, P = 0.034) and Non-micro monovision group (MTF10: 0.55 ± 0.19, P = 0.038; PSF: 0.408 ± 0.285, P = 0.003). Spectacle independence for near vision were higher in both the Micro monovision (45%) and Mixed (55%) group compared to the Non-micro monovision group (40%). The Mixed group also reported higher incidence of photic phenomena (25%). However, there were no significant differences in stereoscopic function among the three groups.

CONCLUSION

Both micro monovision and mix-and-match methods can help patients to obtain better visual outcomes at different distances. Mix-and-match method has better near visual acuity, while micro monovision method has better intermediate visual acuity. Non-micro monovision methods will affect patients' near vision outcomes. Binocularly implanted EDOF IOL has better contrast sensitivity.

CLINICAL TRIAL REGISTRATION

Registration date:11/07/2023.

TRIAL REGISTRATION NUMBER

ChiCTR2300073433.

TRIAL REGISTRY

West China Hospital of Sichuan University retrospectively registered.

Safety, biocompatibility, and potential functionality of a new accommodative intraocular lens: An experimental study in rabbits

This study aims to evaluate the safety, biocompatibility, and functionality of a new accommodative intraocular lens (IOL) (LUZ, patent PCT/ES2016/070,813) after implantation in rabbit eyes. LUZ (Study) and EyeCee® plus a capsular ring (Control) were implanted in rabbits (n = 8 each) after phacoemulsification. Intraoperative follow-up, long-term clinical follow-up, and functional IOL studies were carried out periodically for up to 180 days. A macroscopic examination of the eyeballs to reveal abnormalities and determine the implant centering and a microscopic examination to semi-quantify cell and tissue response were performed. Statistical analysis of the collected data was finally achieved. During follow-up, no significant changes in the general condition nor the clinical evaluation were observed between both groups. However, Study IOL remained centered throughout the study and did not present severe complications as observed in the Control group. Functional studies did not reveal significant differences between both materials. Study showed better centering, fewer adhesions, and maintenance of an opening capsular bag compared to the Control. Local biological effects caused by Study implantation are minimal and comparable to the Control. Therefore, LUZ showed no clinical signs or histological response of adverse reaction to the implanted material, according to UNE-EN ISO 11979-5 and 10993-6. Functionality must be confirmed in another animal species with greater lens accommodation capacity than the rabbit. LUZ keeps the capsular bag open, favoring its centering and avoiding fibrosis and adherence to the bag; this allows potential accommodation of this IOL and theoretically enables the patient to focus dynamically.

Latest Development in Extended Depth-of-Focus Intraocular Lenses: An Update

In recent years, there has been an overwhelming influx of different types of intraocular lenses (IOLs) as treatment for presbyopia. The extended depth-of-focus (EDOF) technology creates a single elongated focal point to enhance depth of focus, in contrast to the multiple foci of multifocal (MF) lenses. In this way, the EDOF lenses aim to reduce photic phenomena, glare, and halos, which have been reported in MF IOLs. A potential disadvantage of this is a blur due to decreased retinal image quality when the amount of the aberrations is increased excessively. Multifocality and EDOF characteristics are not exclusive of each other. Frequently, EDOF IOLs are combined with MF optical designs, a bifocal IOL may exhibit EDOF characteristics, likewise an aspheric monofocal IOL or a diffractive or refractive trifocal IOL. Thus, EDOF lenses are commonly subjected to confusion. A wide range of different types of EDOF lenses are available on the market to surgeons. In this practical update, we aim to clarify what is a true EDOF lens, classify the different types of the EDOF lenses based on their optical principle and review their recently reported outcomes. Comprehensive patient examination and selection, combined with knowledge of the most updated options and adequate patient counseling, can avoid dissatisfaction and yield the desired outcomes.

Recent Advances of Intraocular Lens Materials and Surface Modification in Cataract Surgery

Advances in cataract surgery have increased the demand for intraocular lens (IOL) materials. At present, the progress of IOL materials mainly contains further improving biocompatibility, providing better visual quality and adjustable ability, reducing surgical incision, as well as dealing with complications such as posterior capsular opacification (PCO) and ophthalmitis. The purpose of this review is to describe the research progress of relevant IOL materials classified according to different clinical purposes. The innovation of IOL materials is often based on the common IOL materials on the market, such as silicon and acrylate. Special properties and functions are obtained by adding extra polymers or surface modification. Most of these studies have not yet been commercialized, which requires a large number of clinical trials. But they provide valuable thoughts for the optimization of the IOL function.

Transparent Polymer Blends of Poly(methyl methacrylate) and Poly(propylene glycol)

Polymer blends, obtained by polymerization of methyl methacrylate in the presence of poly(propylene glycol), are investigated. Poly(propylene glycol) acts as a plasticizer, significantly lowering poly(methyl methacrylate)’s glass transition temperature and decreasing its elasticity modulus and yield stress. The mixture of methyl methacrylate with poly(propylene glycol) is more stable than its mixture with currently used poly(ethylene glycol), which leads to more uniform distribution and higher possible content of the plasticizer. Unlike low molecular weight plasticizers, poly(propylene glycol) is less prone to migration and exudation during manufacturing process and in use, and has low toxicity. Dynamic mechanical thermal analysis, compression testing and X-ray diffraction were used to investigate how the properties of the material depend on the content and molecular weight of the poly(propylene glycol) in the polymer blend. It was shown that the dependence of the glass transition temperature of methyl methacrylate polymerized in the presence of poly(propylene glycol) on the molar fraction of propylene glycol units is linear, and poly(propylene glycol) with lower molecular weight affects properties of the material stronger than poly(propylene glycol) with higher molecular weight. Therefore, the addition of poly(propylene glycol) allows to control the properties of poly(methyl methacrylate) easily and within wide range.

The effects of premium intraocular lenses on presbyopia treatments

Background

Presbyopia has become a global disease affecting the world's aging population. Among various treatments, cataract extraction and intraocular lens (IOL) implantation have become the most popular and common methods of presbyopia correction. During the twentieth century, IOLs have underwent significant innovation and advancements to meet the patients' high demands for functional vision at all distances.

Main Text

To meet the increasing needs for excellent near and intermediate vision for daily activities, some premium IOLs with more than one focus have been developed, for example, the refractive MfIOLs, diffractive MfIOLs, extended depth of field (EDOF) IOLs, and accommodating IOLs (AIOLs) were introduced to meet this need. In addition, the add-on MfIOLs have been explored as promising supplementary IOLs for pseudophakic presbyopia. When selecting the MfIOLs, the IOLs' features, patients' characteristics, preoperative eye conditions, and treatment expectations should be considered.

Conclusions

In this review, we focus on the multifocal IOLs (MfIOLs) commonly used for presbyopia correction and systematically summarized their optical designs and clinical outcomes. More evidence-based studies are required to provide guidelines for MfIOL selection, provide maximum visual benefits, and develop personalized visual solutions in the future.

Vision-related Quality of Life after Bilateral Implantation of Monofocal and Multifocal Intraocular Lenses

Purpose

To evaluate vision-related quality of life in two sets of patients after routine cataract surgery implanting with traditional versus multifocal intraocular lens (IOLs).

Methods

In a cross-sectional prospective study, 58 and 33 candidates for cataract surgery were divided into traditional (Acrysof SN60WF, Alcon Laboratories, Inc) and multifocal IOL (AcrySof IQ PanOptix IOL TFNT00, Alcon Laboratories, Inc.) groups, respectively. The primary outcome was VFQ-25 scores. The secondary outcomes were making comparisons between the two IOL types in the near vision and the driving items.

Results

mean patients' age in traditional and multifocal IOL groups was 60.85 ± 7.40 (55% female) and 59.85 ± 8.95 (36% female) years, respectively. The mean VFQ-25 total scores in traditional and multifocal IOL groups before and after surgery were 63.69 ± 4.95 and 72.15 ± 9.66, and 98.08 ± 0.70 and 95.70 ± 1.30, respectively (P = 0.001 & 0.001). The mean scores of night driving in traditional and multifocal IOL groups were 38.79 ± 20.50 and 44.35 ± 21.12 (P = 0.1) before surgery which improved to 97.41 ± 7.68 and 56.45 ± 11.12 after surgery, respectively (P = 0.001). The mean scores of near vision in traditional and multifocal IOL groups were 46.83 ± 10.56 and 50.53 ± 8.58 (P = 0.2) before surgery which improved to 89.94 ± 4.87 and 100.00 ± 0.00 after surgery, respectively (P = 0.001).

Conclusion

Vision-related quality of life after cataract surgery with either type of traditional or multifocal (PanOptix) IOLs improved to an excellent level. Traditional IOLs provided more satisfaction in nighttime driving while multifocal IOLs provided increased satisfaction in near and intermediate vision.

A NOVEL SURGICAL TECHNIQUE FOR RESCUING A DISLOCATED ACCOMMODATIVE INTRAOCULAR LENS (CRYSTALENS)

PURPOSE

To describe a novel surgical technique for rescuing a dislocated "in-the-bag" accommodative intraocular lens (Crystalens; Bausch and Lomb Inc, Rochester NY) and report its postoperative outcome.

METHODS

Interventional case report. An 82-year-old patient with history of pseudoexfoliation syndrome presented with a posteriorly dislocated "in-the-bag" Crystalens intraocular lens. A pars plana vitrectomy was performed. The Crystalens intraocular lens was rescued, and scleral sulcus fixated using prolene suture.

RESULTS

No intraoperative or postoperative complications were noted. The preoperative visual acuity was 6/200. The vision improved to 20/30, 8 weeks after the surgery.

CONCLUSION

Rescuing, instead of exchanging, a Crystalens intraocular lens might be a safe alternative in patients with a dislocated "in-the-bag" Crystalens intraocular lens.

Visual outcomes of binocular implantation of a new extended depth of focus intraocular lens

Purpose:

To evaluate the visual outcomes of bilateral implantation of a new hydrophobic foldable extended depth of focus (EDOF) IOL.

Methods:

All cases undergoing phacoemulsification with bilateral implantation of Supraphob Infocus IOL between December 2017 and July 2018 at a tertiary eye care center were recruited in this prospective interventional study. The primary outcome measures were uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA), and uncorrected near visual acuity (UNVA). Postoperative follow-up was done on day 1, 1 week, 1 month, and 3 months.

Results:

One hundred and four eyes of 52 patients with a mean age of 58.4 ± 9.3 years were included. The mean UDVA improved from 0.84 ± 0.32 logMAR preoperatively to 0.11 ± 0.08 logMAR at 3 months following surgery. At the final follow-up, the binocular UDVA, UIVA, and UNVA was 0.03 ± 0.07, 0.14 ± 0.06, and 0.36 ± 0.05 logMAR, respectively. The mean CS was 1.47 ± 0.06 logCS. The distance and near stereopsis was 90.2 ± 24.8 s of arc (arcsec) and 62.5 ± 19.4 arcsec, respectively. The mean total higher-order aberration (HOA), point spread function, and modulation transfer function were 0.30 ± 0.13, 0.07 ± 0.08, and 0.26 ± 0.07, respectively.

Conclusion:

The Supraphob Infocus EDOF IOL provides good unaided visual acuity for distance, intermediate, and near along with a high quality of vision as assessed by contrast sensitivity, HOAs, and stereoacuity. It may be a potential alternative to the currently available EDOF IOLs in providing good visual acuity at variable distances.

Future Intraocular Lens Technologies

The future of intraocular lens (IOL) technology has already begun with a number of recent innovations. The postoperative change of refractive power will lead to a customized fine-tuning that provides patients with the individual vision they expect and with as much spectacle independence as possible. The latest-generation (2.0) Light-Adjustable Lens (RxSight) was recently introduced into clinical practice, with the first results being very encouraging. Other methods of altering the power of an already implanted IOL are under development. The same can be said about the correction of presbyopia, the so-called last frontier in refractive surgery. Extended depth-of-focus IOLs have been introduced, as has the technology of the pinhole IOL. The latter has therapeutic potential beyond the refractive aspect and has already proven helpful in cases of iris defects and irregular corneas. Several technologies are currently being tested to achieve-finally-an accommodative IOL. One such concept uses the (remaining) strength of the ciliary muscle, whereas another is triggered by the pupil reaction when shifting focus from far to near. Not an IOL itself, but rather a high-tech innovation that so far has mostly been implanted during cataract surgery, is a microelectronic sensor that measures habitual intraocular pressure (IOP) at any given time and promises to revolutionize the management of glaucoma patients. The last generation of this device (Eyemate; Implandata Opthalmics Products GmbH) is implanted during small-incision cataract surgery; the latest development is an even smaller sensor that will be inserted suprachoroidally before, in the near future, such a device will be part of a capsular ring. These IOP sensors are a prime example that IOL technology will continue to be a driving force in ophthalmology, with a positive impact far beyond cataract surgery.

Multifocal and Extended Depth-of-Focus Intraocular Lenses in 2020

Ophthalmic surgeons have been overwhelmed by the influx of multifocal intraocular lens (IOL) options in recent years, with close to 100 IOLs on the market in 2020. This practical and technical update on a representative group of established as well as newly launched multifocal IOLs on the market focuses on multifocal IOLs, including extended depth-of-focus lenses. We also describe the optical basis of lens platforms used and thorough preoperative planning to aid decision making. This allows the surgeon the knowledge base to deliver the required relative customized spectacle independence with the least photic phenomenon and loss of contrast possible while achieving high individual patient satisfaction. Data of reviewed IOLs displayed in tabular format include mean monocular uncorrected distance, intermediate, and near visual acuities (logarithm of the minimum angle of resolution), with standard deviations and ranges where available. The range of vision targeted, pupil dependence, toric availability, as well as type of optical platform, are provided as a practical guide to demystify existing terminology on the market that may create interest around a seemingly new design that is actually not novel at all. Halos and glare experienced, levels of patient satisfaction, and spectacle independence achieved also are summarized. A wide range of multifocal IOLs options are available on the market to surgeons. Comprehensive patient selection and examination, combined with knowledge of the most recent options and adequate patient counseling, including neuroadaptation, can avoid dissatisfaction. Many recently available IOLs are awaiting formal results, but the methods by which we label and compare these types of IOLs must also be standardized.

Lens-based surgical correction of presbyopia. Where are we in 2020?

INTRODUCTION

Presbyopia is the progressive and irreversible loss of accommodation due to aging. It is one of the main causes of loss of quality of life in people from 45 years of age, due to the, often novel, dependence on spectacles. The eagerness to correct it by ophthalmologists impulsed by the desire of millions of people who suffer from it, has become one of the main drivers for the development of intraocular lens (IOL) technology over the last twenty years.

MATERIAL AND METHODS

This review briefly presents the different alternatives that have allowed us to improve the crystalline lens surgical approach of presbyopia; from monofocal lenses and monovision technique, accommodative, refractive, and diffractive multifocal lenses, and finally the most recent extended depth of focus/field lenses known as EDOFs.

RESULTS

Each IOL has its advantages, limitations and disadvantages. Furthermore, there is no single lens that suits the needs of all patients.

CONCLUSIONS

It is necessary to know the variety of lenses available, and to have an in-depth understanding of their optical properties, as well as the impact that these will have later on their clinical performance and on the visual quality of the patients. This should help us to select the best alternative for each of them.

Which intraocular lens would ophthalmologists choose for themselves?

PURPOSE

Contemporary cataract surgery is increasingly customizable with the advent of presbyopia-correcting intraocular lenses (IOLs) and the femtosecond laser. The purpose of this study was to determine the types of IOLs ophthalmologists choose for themselves and whether demographic characteristics, surgical experience, and attitudes of ophthalmologists might influence their decision-making. Additional goals included evaluating the use of femtosecond laser use in cataract surgery and investigating surgeon IOL preferences for their patients.

METHODS

We distributed a 29-question Survey Monkey survey to senior ophthalmology residents and practicing ophthalmologists and received 347 responses during a 1-month period. We analyzed 328 surveys using chi-square tests and Fisher's exact tests.

RESULTS

Main outcome measures included surgeons' personal preferences for choice of IOL, femtosecond laser-assisted cataract surgery, and IOL preference for patients. In the setting of no astigmatism, 61.3% of respondents would choose a monofocal IOL set for either distance or monovision for their own surgery. For corneal astigmatism >1.25 D, 60.3% of respondents would choose a toric monofocal lens and only 6.9% would want a femtosecond laser or manual LRI for their own surgery. Of the respondents, 34.6% perform femtosecond laser-assisted cataract surgery, but only 15.3% would want femtosecond cataract surgery performed on themselves. Also, 67.7% implant presbyopia-correcting IOLs (diffractive echelette, multifocal, or accommodative). When correcting for patients' corneal astigmatism >1.25 D, 65.7% of respondents preferred a toric monofocal IOL.

CONCLUSION

Ophthalmologists value quality of vision and are risk averse. Overall, a surgeons' personal preference for their own surgery is correlated with past surgical experience with patients.

Small aperture IC-8 intraocular lens in cataract patients: achieving extended depth of focus through small aperture optics

BACKGROUND

To investigate visual outcomes following cataract surgery in patients who were implanted monocularly with an extended range of focus IC-8 IOL.

METHODS

A multicentre, non-randomised, retrospective case series of 126 consecutive patients implanted with the IC-8 IOL. Data were collected and pooled from six centres across Australia. Uncorrected distance visual acuity (UDVA), uncorrected intermediate visual acuity (UIVA) at 80 cm and uncorrected near visual acuity (UNVA) at 40 cm were measured in eyes implanted with the IC-8 IOL. Adverse events, spectacle independence, visual symptoms and patient satisfaction were assessed at final follow-up.

RESULTS

Over 90% of the patients without pre-existing ocular pathology (n = 109) achieved UDVA, UIVA and UNVA of 6/12 or better in the IC-8 eye. Binocularly, in this group, 98% achieved UDVA of 6/9, 94% UIVA of 6/12 and 91% UNVA of 6/12 or better. By final follow-up, over 50% of patients reported complete spectacle independence for distance, intermediate and near visual activity, with the remainder only using spectacles for specific tasks such as near-vision hobbies and reading in dim light.

CONCLUSIONS

The IC-8 IOL is capable of providing extended depth of focus following cataract surgery. It allows complete spectacle independence in more than half of the patients implanted with the IC-8 IOL.

Presbyopia: Effectiveness of correction strategies

Presbyopia is a global problem affecting over a billion people worldwide. The prevalence of unmanaged presbyopia is as high as 50% of those over 50 years of age in developing world populations, due to a lack of awareness and accessibility to affordable treatment, and is even as high as 34% in developed countries. Definitions of presbyopia are inconsistent and varied, so we propose a redefinition that states "presbyopia occurs when the physiologically normal age-related reduction in the eye's focusing range reaches a point, when optimally corrected for distance vision, that the clarity of vision at near is insufficient to satisfy an individual's requirements". Strategies for correcting presbyopia include separate optical devices located in front of the visual system (reading glasses) or a change in the direction of gaze to view through optical zones of different optical powers (bifocal, trifocal or progressive addition spectacle lenses), monovision (with contact lenses, intraocular lenses, laser refractive surgery and corneal collagen shrinkage), simultaneous images (with contact lenses, intraocular lenses and corneal inlays), pinhole depth of focus expansion (with intraocular lenses, corneal inlays and pharmaceuticals), crystalline lens softening (with lasers or pharmaceuticals) or restored dynamics (with 'accommodating' intraocular lenses, scleral expansion techniques and ciliary muscle electrostimulation); these strategies may be applied differently to the two eyes to optimise the range of clear focus for an individual's task requirements and minimise adverse visual effects. However, none fully overcome presbyopia in all patients. While the restoration of natural accommodation or an equivalent remains elusive, guidance is given on presbyopic correction evaluation techniques.

Clinical application of accommodating intraocular lens

The present review describes recent advances in application of accommodating intraocular lenses (AIOLs). Standard monofocal intraocular lenses (MIOLs) only correct distance vision, while AIOLs are designed to allow both good distance vision and near vision, which is achieved through the contraction and relaxation of ciliary muscles by providing transformation of the axial movement or curvature of the lens. Thus, AIOLs may be a better choice for those patients who demand a higher level of visual performance. Since techniques to analyze the performance of AIOLs have not been standardized, and there is a variety of both subjective and objective methods, it is hard to measure the performance of these intraocular lenses. By evaluating advantages and disadvantages of various AIOLs, and introducing techniques for measurement the performance postoperative, this paper can provide some relative information on choosing the type of AIOLs in the clinic.

Correction of presbyopia: An integrated update for the practical surgeon

Presbyopia results from loss or insufficiency of the eye's accommodative ability, and clinically manifests as the inability to focus near objects on the retina. It is one of the most common causes of visual impairment worldwide especially in adults of productive or working age. Various means of compensating for the loss of accommodative ability have been devised from optical tools such as spectacles and contact lenses, to topical medications and to surgical procedures. A comprehensive search on journal articles about topical and surgical correction of presbyopia was undertaken. The various techniques for presbyopia correction, as enumerated in these articles, are discussed in this paper with the addition of our personal experience and perspective on the future of these techniques.

Cataracts

An estimated 95 million people worldwide are affected by cataract. Cataract still remains the leading cause of blindness in middle-income and low-income countries. With the advancement of surgical technology and techniques, cataract surgery has evolved to small-incisional surgery with rapid visual recovery, good visual outcomes, and minimal complications in most patients. With the development of advanced technology in intraocular lenses, the combined treatment of cataract and astigmatism or presbyopia, or both, is possible. Paediatric cataracts have a different pathogenesis, surgical concerns, and postoperative clinical course from those of age-related cataracts, and the visual outcome is multifactorial and dependent on postoperative visual rehabilitation. New developments in cataract surgery will continue to improve the visual, anatomical, and patient-reported outcomes. Future work should focus on promoting the accessibility and quality of cataract surgery in developing countries.