Development of a novel multifocal lens using a polarization directed flat lens: possible candidate for a multifocal intraocular lens

Background A polarization-directed flat (PDF) lens acts as a converging lens with a focal length (f) > 0 and a diverging lens with f < 0, depending on the polarization state of the incidental light. To produce a multifocal lens with two focal lengths, a PDF and a converging lens having shorter focal length were combined. In this study, we tested a bifocal PDF to determine its potential as a new multifocal intraocular lens (IOL). Methods Constructed a multifocal lens with a PDF lens (f = +/− 100 mm) and a converging lens (f = + 25 mm). In an optical bench test, we measured the defocus curve to test the multifocal function. The multifocal function and optical quality of the lens in various situations were tested. An Early Treatment Diabetic Retinopathy Study (ETDRS) chart as a near target and a building as a distant target were photographed using a digital single-lens reflex (DSLR) camera. Both lenses (multifocal and monofocal) were tested under the same conditions. Results For the 0 D and − 20 D focal points, the multifocal lens showed sharp images in the optical bench test. In the DSLR test using the multifocal lens, the building appeared slightly blurry compared with the results using the monofocal lens. With the multifocal lens, the ETDRS chart’s images became blurry as the ETDRS chart’s distance decreased, but became very clear again at a certain position. Conclusions We confirmed the multifocal function of the multifocal lens using a PDF lens. This lens can be used as a multifocal IOL in the future.

Implantation of multifocal lens in cataract surgery in patients after vitreoretinal surgery

Purpose. To study the results of cataract surgery with implantation of multifocal IOLs in patients with various retinal pathologies who underwent vitreoretinal surgery. Material and мethods. Fifteen patients who had previously undergone vitreoretinal interventions for macular hole (n=6), epiretinal membrane (n=4) and retinal detachment (n=5) were observed. The criterion for choosing in favor of multifocal lens implantation was high visual acuity (0.7 or more) after undergoing vitreoretinal surgery. All patients underwent cataract phacoemulsification with implantation of two types of multifocal lenses: I group – IOL with an extended near focus (EDOF) (n=8) and II group – with a multifocal three-focus lens (n=7 eyes), including, in 3 cases – with toric component. In 55% of cases, the operation was performed on both eyes. The age of the patients varied from 34 to 59 years (51.4 ± 6.1 years). Results. Long-distance uncorrected visual acuity varied from 0.7 to 1.0 (0.85±0.25), which did not depend on the type of intraocular lens and correlated with morphological changes in the macular region of the retina. The highest uncorrected visual acuity (0.8±0.14) at an intermediate and near distance (0.75±0.25) was achieved in I group of patients. Postoperative spherical equivalent after 1 month corresponded to the planned target refraction (Em±0.5 diopters) in 14 cases and remained stable during 12 months of observation. In general, subjective satisfaction with MIOL implantation was higher in patients in II group, which was explained by minimal changes in the macular region of the retina. Additional spectacle correction for near was required for a patient of I group with a history of macular rupture, who underwent bilateral multifocal IOL implantation with high uncorrected visual acuity in the distance (OD=1.0 \ OS=1.0) and near (OD=0.6 \ OS=0,5). Conclusion. Implantation of multifocal lenses in patients with a good anatomical and functional outcome of vitreoretinal surgery allows obtaining high and stable functional results. Bilateral implantation of a multifocal lens with an extended near focus in patients with operated macular pathology does not cause specific adaptive difficulties in binocular vision. The choice in favor of multifocal lens implantation in patients with vitreoretinal pathology requires an individual approach and careful selection. Key words: multifocal lens, cataract, macular hole, retinal detachment, epiretinal membrane.

How Contact Lenses Have Influenced Research Developments in Optics and Vision Science

Initially, contact lenses were developed as the only viable option to provide improved vision for patients suffering from conditions which distortedthe corneal surface in an irregular fashion, rendering spectacle correction an unsatisfactory option. Developments in materials, fitting methods andmanufacturing technologies soon made contact lenses an appealing option for all spectacle wearers, particularly with the development of toricand multifocal lens options. Although the optical challenges of contact lenses appeared to be relatively straightforward in their early years, thedevelopment of improved in-vivo diagnostic and in-vitro metrology instrumentation led to a significantly greater understanding of the nature of theoptical errors (e.g. higher order wavefront aberrations) of the eye and contact lenses and the interactions between them when worn. The featuresof contact lenses having extremely steep curvatures and being aligned closely to the eye’s visual axis in all positions of gaze provide both uniquechallenges and opportunities for improving the visual performance of both physiological and pathological eyes, and have guided the efforts ofsignificant vison science research in more recent times.

The “Tempered Radical” Revolution: Multifocal Strategies of Religious-Zionist Feminism in Israel

Agunah activism, a flagship struggle of Religious-Zionist feminism, links gender politics, Jewish-Orthodox politics, and national Israeli politics. This qualitative study focuses on agunah activists’ strategies and conceptions of change, highlighting the complex ways religious women radically transform conservative contexts, complicated by intersections of religion, gender, and state. It examines dynamic boundary-work and how activists deploy the inner workings of “the Halakhic framework” to shift creatively between social positioning, ideological or cultural positioning, and a political positioning to create “change from within”. My case study troubles the premise that religion and feminism are antithetical, and that distinct identities or set social locations predetermine social movements’ frames or actions. I expand upon the term “tempered radicals” which challenges reformist/revolutionary and conservative/radical binaries. “Tempered radical” strategies are two-pronged: a tempered mode of modulation and moderation to rock the boat without falling out (avoid the red lines, find “the right way”) and a radical mode of stirring the sea and creating horizons (arrive there, one way or another). Dynamically holding both modes together, through a “multifocal lens”—the world-as-it-is and the world-as-it-should-be—enables their strategic maneuverings. They remain “within” while radically transforming individuals, communities, Jewish law, Orthodox society and the Israeli public sphere. This study demonstrates how religious and gendered structures are at once constitutive and mutable.

Clinical outcomes of the piggyback secondary implantation of a novel multifocal lens in the ciliary sulcus: A case series

Purpose: Evaluate the clinical outcomes of the secondary piggyback add-on IOL implantation in the ciliary sulcus for pseudophakic patients previously implanted with a monofocal IOL, who pursue a spectacle-free option after IOL surgery. Methods: A prospective case series including seven pseudophakic patients who underwent an in-the-bag monofocal IOL implantation. All eyes underwent a piggyback IOL implantation of the new sulcus designed A4 AddOn IOL in the ciliary sulcus as a secondary procedure for pseudophakic patients pursuing a spectacle-free option for near and intermediate distance after IOL surgery. Results: Seven eyes from six patients were included in this study, from which 4 (71.43%) were female, with a mean age of 58.33 ± 3.5 years (range 54–63; 95% CI 54.66, 62.01). The postoperative spherical equivalent at the 3-month visit was −0.10 m ± 0.82. Also, the UDVA was 0.11 ± 0.08 logMAR, the UIVA 0.01 ± 0.03, and the UNVA 0.01 ± 0.03 3 months after their surgical procedure. Conclusions: The A4 AddOn multifocal IOL’s secondary piggyback implant is an efficient alternative for monofocal pseudophakic patients seeking presbyopia solutions. This sulcus-designed IOL provides an optimal visual outcome for near and distance vision.

Development of a novel multifocal lens using a polarization directed flat lens: Possible candidate for a multifocal intraocular lens

Background: A polarization-directed flat (PDF) lens acts as a converging lens with a focal length (f) > 0 and a diverging lens with f < 0, depending on the polarization state of the incidental light. To produce a multifocal lens with two focal lengths, a PDF and a converging lens having shorter focal length were combined. In this study, we tested to determine its potential as a new multifocal intraocular lens (IOL).Methods: Constructed a multifocal lens with a PDF lens (f=+/- 100 mm) and a converging lens (f= +50 mm). In an optical bench test, we measured the lens’s focal lengths to test the multifocal function. The multifocal function and optical quality of the lens in various situations were tested. An Early Treatment Diabetic Retinopathy Study (ETDRS) chart as a near target and a parking lot as a distant target were photographed using a digital single-lens reflex (DSLR) camera. Both lenses (multifocal and monofocal) were tested under same conditions. Results: In the optical bench test, the multifocal lens’s focal lengths were 31.2 and 71.2 mm. In the DSLR test using the multifocal lens, the parking lot appeared slightly cloudy compared to the monofocal lens results. With the multifocal lens, the ETDRS chart’s images became blurry as the ETDRS chart’s distance decreased, but became very clear again at a certain position.Conclusions: We confirmed the multifocal function of the multifocal lens using a PDF lens. This lens can be used as a multifocal IOL in the future.