Intraocular Lens Design Research Articles

Posterior capsular Opacification: Pathogenesis, challenges, and innovative therapeutic strategies.

To analyze the difference in objective and subjective photic phenomena following virtual implantation of three different presbyopia-correcting diffractive intraocular lens (IOL) designs. The study was conducted at JENVIS Research Germany. A prospective cross-over and double-masked trial design was used. Seventy-four healthy individuals without cataract (age: 18 to 50 years) were enrolled. All participants assessed photic phenomena with three diffractive IOL designs by virtual implantation using the VirtIOL device (10Lens S.L.U), which allows participants to view through the IOL imaged at the iris plane as if it were implanted: IOL A (Tecnis Synergy ZFR00V; J&J Vision), IOL B (AcrySof IQ PanOptix TFNT00; Alcon Laboratories, Inc), and IOL C (AT ELANA 841P; Carl Zeiss Meditec). The size of the starburst and annular light pattern was measured in degrees, and participants were asked about their preference in terms of quality of night vision when comparing by pairs the IOLs. The starburst pattern size was significantly larger with IOL A (5.54 ± 0.62º) compared to the IOLs B (3.82 ± 0.90º, P < .001) and C (3.65 ± 0.57º, P < .001). However, there were no significant differences between IOLs B and C (P = .078). Regarding the induced annular light pattern, no significant differences were found between IOLs (P > .05). In a pairwise short-term comparison of the IOLs using a simulated night scene with a glare source, participant preference was in favor of IOL C (P < .001). IOL A had objectively a significantly larger starburst pattern than the other two. In a short-term comparison, the new trifocal IOL C was significantly preferred in a night driving scene.

'Seeing both sides': A systematic review of the Miyake-Apple video system's role in ophthalmology.

Background:Recent innovations in intraocular lens (IOL) design have introduced extended depth of focus lenses, which has shown promise in improving visual acuity at multiple distances while preserving the distance vision provided by a standard monofocal IOL. This study aimed to evaluate the visual outcomes of TECNIS Eyhance, a monofocal IOL with enhanced intermediate function, and a standard TECNIS monofocal 1-piece IOL, and to review published studies comparing the clinical performance between the TECNIS Eyhance and standard IOLs.Methods: A retrospective analysis was conducted on patients who underwent cataract extraction with bilateral implantation of either TECNIS Eyhance IOLs or TECNIS Monofocal 1-Piece IOLs. Primary outcomes included monocular and binocular uncorrected distance visual acuity (UDVA), uncorrected near visual acuity (UNVA), and corrected distance visual acuity (CDVA), and manifest refraction. Outcomes such as glare, halos, and dry eye were also assessed. A literature review was performed to identify studies evaluating the clinical outcomes of TECNIS Eyhance and standard TECNIS monofocal IOLs.Results: In total 108 patients (216 eyes) underwent bilateral implantation with either TECNIS Eyhance (104 eyes) or TECNIS Monofocal 1-Piece (112 eyes) IOLs. The mean (standard deviation [SD]) binocular UNVA was better in the Eyhance group at 1 month (0.18 [0.13] logMAR) compared to the standard monofocal group (0.24 [0.14] logMAR; P < 0.05). A greater proportion of Eyhance patients achieved binocular UNVA of 20/25 or better (46.9% vs 21.8%; P < 0.01), and 20/32 or better (65.3% vs 45.5%; P < 0.05). However, there was no significant difference for 20/20 visual acuity (20.4% vs 18.2%; P > 0.05). No significant differences were observed in postoperative UDVA or CDVA between groups (both P > 0.05). The mean (SD) monocular UNVA showed a slight, but non-significant, advantage in the Eyhance group (0.26 [0.15] logMAR vs 0.29 [0.15] logMAR; P > 0.05). Eyhance eyes demonstrated less residual refractive cylinder at 1 month (P < 0.01), which may be attributed to a higher rate of toric IOL use (P < 0.01). Patient-reported visual symptoms did not differ between groups. Thirteen studies were identified that compared the Eyhance and standard monofocal IOLs. Across the studies analyzed, the Eyhance group showed better monocular and binocular UNVA with mean (SD) differences of - 0.10 (0.20) logMAR and - 0.10 (0.21) logMAR, respectively (both P < 0.01), as well as improved binocular uncorrected intermediate visual acuity (UIVA) (mean difference [SD]: -0.10 [0.18] logMAR; P < 0.01). These studies also showed low rates of glare and halos for both IOLs.Conclusions:Patients receiving the TECNIS Eyhance IOL had better binocular UNVA compared to those with a standard monofocal IOL, consistent with published literature. The Eyhance IOL also showed better binocular UIVA and monocular UNVA across the studies reviewed. Both enhanced and standard monofocal IOLs demonstrate excellent distance vision and have similar levels of photic phenomena. Nevertheless, the Eyhance IOL shows promising potential for improving intermediate and near vision.

Supplementary intraocular lenses (IOLs) are used to correct spherical and astigmatic refractive errors after cataract surgery. They provide patients with improved uncorrected visual acuity, resulting in ahigher degree of spectacle independence. For the implantation of supplementary IOLs two approaches are distinguished: the primary and secondary Duet procedures. Indications include extreme refractive errors, desire for reversible multifocality, residual refractive errors and pediatric cataract surgery. Monofocal, extended depth of focus (EDOF) and multifocal implants are available, some also as toric variants. Thanks to specialized IOL designs, supplementary IOLs have been optimized for implantation in the ciliary sulcus, making the procedure safe, effective and associated with minimal complications. Several studies have demonstrated the favorable safety profile, predictable refractive outcomes and improvement in uncorrected visual acuity. Continuous advancements in IOL design, including the availability of EDOF and multifocal implants, have further enhanced the benefits of supplementary IOLs. Through arelatively small, low-risk and quick procedure, individualized solutions can be provided for many patients, improving vision and reducing spectacle dependence.

This review examines the optical principles underlying presbyopia-correcting simultaneous vision intraocular lenses (IOLs), providing a fundamental, physics-based perspective on their function. Rather than focusing on commercial models or clinical outcomes, this work aims to enhance the understanding of the optical mechanisms governing simultaneous vision. The discussion covers key design variations in both refractive and diffractive IOLs, explaining how wavefront modulation can affect light distribution and visual performance. The analysis is presented from the dual perspectives of a former eyecare practitioner and a vision scientist experienced in the research and development of presbyopia-correcting IOLs. The review uses accessible language aimed at nonphysicists and uses accurate optical simulations and general design representations to illustrate the optical principles of contemporary presbyopia-correcting IOLs. Although variations in lens geometry and material properties influence optical performance, the core concept remains consistent. By elucidating the fundamental physical principles behind modern IOL designs, this review aims to enhance professional knowledge and provide a robust foundation for evaluating emerging technologies and developing innovative solutions for presbyopia correction.

Accurate central surface radius of curvature (RoC) measurements of isolated human lenses are essential for understanding the zonular forces required to modify human lens shape to focus at near; i.e., accommodate. The human lens can be described as an encapsulated oblate spheroid, with its minor axis aligned with its optical axis. The lens is suspended by zonular fibers that originate from the epithelium of the ciliary body and insert into the equatorial region of the lens capsule. According to Helmholtz's theory of accommodation when the eye views a distant object (the unaccommodated state), the ciliary muscle is fully relaxed and the zonules are under maximal tension. This tension flattens both the central and peripheral lens surfaces resulting in minimal central optical power (COP). During near focus (accommodation), contraction of the ciliary muscle reduces zonular tension, allowing the elastic capsule to restore the lens to a more rounded shape. This increases the curvature of the lens surfaces, central thickness, and COP. Consequently, isolated lenses without zonular tension from young donors (20-30 years old) would be expected to exhibit maximum COP. However, the companion independent profilometric equation fitting study found that, within central optical zones ≤ 3 mm, 10 fresh isolated lenses from donors in this age range actually had minimal COP. The present study utilizes a white light scanning interferometer (WLSI) with a 10x objective that was validated by measuring RoCs of glass and porcine lenses. Fourteen transparent human lenses were obtained from both eyes of seven donors aged 20-30 years of whom 2 were female and 5 were male. One lens of each donor was placed in preservative media and the contralateral lens in culture media within 11:26 ± 5:15 (range: 4:47-21:54) of the donor's death. Two of the lenses stored in the culture media had torn capsules and were excluded from the study. Central thickness and WLSI surface vertex RoCs of 12 lenses were measured within 16:27 ± 5:22 (range: 10:11-25:33) of the donor's death. Mean central thickness, anterior and posterior vertex RoCs and COP were 3.54 ± 0.07 mm, 10.2 ± 0.9 mm, 6.8 ± 1.0 mm, and 20.7 ± 2.1 diopters, respectively. These results confirm the companion study that isolated human lenses have low COP consistent with the unaccommodated state of lenses in vivo. Therefore, relaxation of all the zonules does not increase COP and cannot be the basis for the mechanism of accommodation. These results have implications for the development and treatment of myopia, presbyopia, glaucoma, cortical cataracts and design of accommodative intraocular lenses.

This article highlights the significant impact of complications following intraocular lens (IOL) implantation on visual recovery and quality of life, urging a multifaceted approach to address these challenges. The author discusses the clinical complexities of IOL opacification, uveitis-glaucoma-hyphema syndrome, capsular block syndrome, and optical disturbances, which are often overlooked or misdiagnosed. A comprehensive strategy involving optimized IOL design, enhanced clinical recognition, and improved patient communication is advocated. Continued research into new materials and techniques, alongside standardized clinical practices, is proposed to improve surgical safety and patient satisfaction.

Artificial Intraocular Lenses-the Halcyon Years as Measured by Individual and Corporate Patentable Innovations.

To assess changes in the demographics and ocular biometric characteristics of cataract patients over the past decade to identify trends that may impact cataract surgery as well as design and selection of intraocular lenses. Retrospective study. Clinicodemographic and ocular biometric data from swept-source optical coherence tomography were retrospectively analyzed for 25,192 eyes of 25,192 patients aged 40 and older who underwent cataract surgery between 2020 and 2023 at West China Hospital of Sichuan University. As patient age increased, axial length, anterior chamber depth, aqueous depth, and white-to-white tended to decrease, whereas corneal refractive power and lens thickness tended to increase. Among all patients, 19.66% had axial lengths exceeding 26 mm, and 1.72% had a history of refractive surgery; the incidence of such surgery increased significantly from 2020 to 2023. Compared to patients without a history of refractive surgery, those with such a history were 12 years younger and larger proportions had axial lengths exceeding 26 mm or corneal refractive power below 38 D. The frequencies of high myopia and of previous refractive surgery among cataract patients increased between the 2010s and the 2020s, and the age of cataract patients at the time of surgery fell during that interval. These changes in ocular and demographic characteristics may necessitate updates in preparations before cataract surgery, procedures during surgery, management after surgery, as well as design and selection of intraocular lenses.

This bibliometric analysis explores the current status and trends of global research on posterior capsular opacification (PCO). A search of the Web of Science Core Collection (WoSCC) database was conducted to identify publications on PCO from 2011 to 2023. Bibliometric analysis was used to explore publication trends in PCO-related research. VOSviewer v.1.6.20 was used to visualize country, institution and author productivity and collaborations, as well as research hotspots. CiteSpace 6.3.R1 was applied to extract the burst references and keywords. A total of 988 PCO-related documents were included. The largest number of publications (283) and citations (3538) were from China. Of these, the largest number of publications (41) and citations (655) were from Wenzhou Medical University. Quankui Lin published 31 articles and was the most productive author. The journal with the highest productivity (121 publications) was the Journal of Cataract and Refractive Surgery. The top 3 cited references mainly presented intraocular lens (IOL) optic material/design and surgical technique on the development of PCO; the mechanism of PCO formation. The keywords mainly formed 5 clusters: the prevalence and risk factors for PCO; the mechanism of PCO formation; the material and design of IOLs and their application in the prevention of PCO; the application of IOLs surface modification and drug delivery in the prevention of PCO; and complications associated with Nd:YAG laser capsulotomy. Based on the raw data from WoSCC, analyzing research hotspots can offer valuable insights into PCO studies.

Sir Harold Ridley (1906-2001) and His Cure for Aphakia: New Historical Insights Into the Invention of the Intraocular Lens.

Intraocular lens (IOL) exchange is performed to treat severe IOL-related complications. There is little published data on the impact of this procedure on the refractive outcomes and intra- and postoperative complications, especially in otherwise healthy eyes. We investigated the refractive outcome of IOL exchange surgery, including corneal aberrations; additionally, we assessed the influence of different IOL characteristics on intraoperative and postoperative complications. This prospective clinical study included 35 eyes with homogenous IOL calcification without other ocular pathologies. Using Pentacam AXL Wave (Oculus Optikgeräte GmbH, Wetzlar, Germany), corrected distance visual acuity (CDVA), target refraction compared to the postoperative spherical equivalent, corneal topography and lower and higher-order aberrations were assessed preoperatively and from 3 months after surgery. Intraoperative and postoperative complications were recorded and compared between different IOL characteristics. The secondary IOL in 53% of cases, was a retropupillary iris-fixated Artisan Aphakia (Ophtec BV, Groningen, Netherlands), 37% had a sulcus-fixated AR40e (Johnson & Johnson Vision, Irvine, USA), and 10% had a capsular bag IOL. The CDVA improved from 0.16 ± 0.14 to 0.07 ± 0.14 logMAR (p = 0.04). In most cases, the target refraction was within ± 1.0 D (Artisan: 71%, AR40e: 90%, Capsular: 100%). IOL exchange did not induce relevant change in corneal aberrations. Anterior (81%) and posterior (78%) vitrectomy were performed in most cases. The haptic design of the primary IOL did not impact intra- or postoperative complications. Although exchanging an IOL involves greater surgery compared to the initial IOL implantation, visual and refractive outcomes are good, and the exchange does not cause relevant change in aberrations. Intra- and postoperative complications are mostly mild and resolve without sequelae.

The standard surgical procedure for treating cataracts uses intraocular lens (IOL) implants that produce consistent results. Among millions of global cases annually, postoperative complications involving IOL surface deposits occur in less than 1% of patients. The diagnostic and therapeutic challenges in delayed-onset sterile IOL precipitates remain significant because these complications are both uncommon and present atypically. The presented review examines an unusual case where fibrotic gray-white deposits formed on the anterior IOL surface eight months post-surgery without any intraocular inflammatory indicators. Visual acuity declined from the condition until topical corticosteroids provided a dramatic response, which proved the sterile inflammatory origin of the condition. The presented case establishes a base for discussing the pathophysiology, classification, differential diagnosis, and management of IOL surface deposits. The proper diagnosis of IOL surface deposits requires clinicians to differentiate them from genuine lens opacification as well as from both infectious endophthalmitis and toxic anterior segment syndrome (TASS) because incorrect diagnoses could lead to unnecessary surgical procedures. The review discusses how patients with previous uveitis experience clinical effects and investigates the predictive power of statistical and AI-based models for identifying at-risk cases, as well as future needs for IOL design and postoperative imaging research. The appropriate management of sterile IOL deposits remains essential to protect vision and prevent invasive interventions, particularly for patients who have complex inflammatory backgrounds.

Today, cataract surgery is almost always accompanied with aphakia correction by implantation of an intraocular lens (IOL). In addition to the constant improvement of surgical techniques, special IOLs with improved characteristics are being developed, allowing any optical task to be solved with a minimum of side effects. Since the appearance of the first polymethyl methacrylate IOL, flexible silicone and acrylic IOLs have become available, and the optical design of the lens allows a choice between a single and multiple foci or increased depth of field within a single focus. Optimization of the material, shape and optical design of IOLs remain.

The magnitude of zonular forces required to change the shape of the human lens while focusing at near; i.e., accommodating, is still under investigation. During accommodation, ciliary muscle contraction induces a large increase in lens central optical power (COP). Here we used finite element (FE) analysis to evaluate the correlation between zonular forces and lens surface curvatures, central thickness, COP, overall lens shape and longitudinal spherical aberration (LSA). Fresh isolated lenses from donors aged 20, 24, 26, and 30 years were the basis for the analyses. Lens nucleus elastic moduli were specified as equal to, 2, 3, 10, 20 and 30 times greater than its cortex. When equatorial zonular (Ez) force was increased in 3.125 x 10-6 N steps while the anterior zonular (Az) and posterior zonular (Pz) forces were decreased in 3.125 x 10-6 N steps, COP was evaluated. Independent of the increase in lens nuclear modulus, less than 0.02 N of Ez force was required to increase COP 10 diopters while Az and Pz forces were decreased. The lens peripheral surfaces flattened, central surfaces steepened, central lens thickness increased, COP increased and LSA shifted in the negative direction consistent with published in vivo accommodation studies. The minimal Ez force required to obtain 10 diopters of COP increase supports that increasing Ez force with decreasing Az and Pz force is the basis for the change in lens shape during accommodation. Since the COP increase was independent of increasing elastic modulus of the nucleus, stiffening of the lens nucleus is not the etiology of the universal age-related decline in accommodative amplitude that results in presbyopia in the fifth decade of life. Increased Ez zonular tension during accommodation has implications for the development and potential treatments of myopia, glaucoma, presbyopia, cortical cataracts and accommodative intraocular lens design.

Cataract surgery, a transformative procedure to restore vision, has seen remarkable advancements in intraocular lens (IOL) technologies. This special issue presents a collection of research that explores the performance, design, and evaluation of IOLs. From established designs and the impact of key optical parameters to innovative approaches and preoperative simulations, these contributions offer a comprehensive view of current trends and future directions in IOL development. The special issue also honors the legacy of Prof. Jim Schwiegerling whose contributions to visual optics in general, and IOLs in particular, have had a tremendous impact in the field, both in the academic, clinical and industrial communities.

Cataract surgery, a transformative procedure to restore vision, has seen remarkable advancements in intraocular lens (IOL) technologies. This special issue presents a collection of research that explores the performance, design, and evaluation of IOLs. From established designs and the impact of key optical parameters to innovative approaches and preoperative simulations, these contributions offer a comprehensive view of current trends and future directions in IOL development. The special issue also honors the legacy of Prof. Jim Schwiegerling whose contributions to visual optics in general, and IOLs in particular, have had a tremendous impact in the field, both in the academic, clinical and industrial communities.

Astigmatism-correction has gradually become a design hotspot in the field of intraocular lenses (IOLs). We proposed what we believe to be a novel diffractive method to design intraocular lenses with both astigmatism-correction at different distance. First, the principle of the diffractive method to achieve astigmatism-correction is given. Different from traditional diffractive optical elements, the surface distribution of diffractive period under the proposed method is elliptical. Then, in order to verify the effectiveness of the method, we give the example of diffractive astigmatism-correcting IOL. The results show that the method can realize the correction of the astigmatism at different distance. As the beginning of diffractive astigmatism design, the method provides what's believed to be a new and convenient method for the design of diffractive astigmatism intraocular lens instead of using the traditional method of changing different axes curvature radius.

Cataract surgery requires selecting an intraocular lens (IOL), whose design affects visual outcomes. Traditional IOL evaluation relies on optical models and bench testing, but these methods fall short in simulating perceptual factors crucial to patient experience. Visual simulators, based on different principles including adaptive optics, temporal multiplexing or physical projection of the IOLs, now allow patients and clinicians to preview and compare different IOL designs preoperatively. By simulating real-world interactions of the eye's optics and the visual system with IOLs, these simulators enhance the patient decision-making process, enable personalized cataract surgery, and can aid in regulatory assessments of IOLs by incorporating pre-operative patient-reported visual outcomes. Visual simulators incorporate deformable mirrors, spatial light modulators and optotunable lenses as dynamic elements to simulate monofocal, multifocal and extended depth-of-focus IOLs, including newer designs aimed at improving contrast sensitivity, expanding depth of focus, and minimizing visual disturbances. With ongoing advancements, these simulators hold potential for transforming IOL design, regulatory processes, and patient care by providing realistic and patient-centered visual assessments, ultimately leading to more successful, individualized surgical outcomes.