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Sub-wavelength focusing based on all-dielectric polarization-independent metalens
摘要： We have proposed an all-dielectric polarization-independent metalens, which can be used for sub-wavelength focusing. The phase discontinuity of transmission light is produced by varying the diameter of the nanopillar. In this way, the incident light can be focused into sub-wavelength spot. Besides, finite-difference time-domain results show that near diffraction limit focusing is realized for the wavelength from 580 nm to 750 nm, which means the proposed metalens possesses a broad operation bandwidth. This all-dielectric metalens features polarization independent and broad bandwidth, and thus promises great potential for the applications of nanolithography, dense storage and biophotonics.
关键词： metamaterials,Lenses,polarization
更新于2025-09-10 09:29:36
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Scleral-sutured intraocular lenses: Single-surgeon technique for suture-preloaded intraocular lens insertion through a small-incision corneal wound
摘要： For scleral intraocular lens (IOL) fixation, suture-loaded IOLs have traditionally been folded in half with a forceps and delivered intraocularly through 3.5 to 4.0 mm corneal wounds. We describe a technique in which a suture-loaded scleral IOL is inserted through a small-incision corneal wound using 2 widely available ocular surgery tools; that is, a C or D cartridge and a Bowman nasolacrimal duct probe. This technique is easy to replicate and can be performed without an assisting surgeon.
关键词： single-surgeon technique,scleral-sutured intraocular lenses,suture-preloaded intraocular lens insertion,small-incision corneal wound
更新于2025-09-09 09:28:46
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[Institution of Engineering and Technology 7th International Conference on Imaging for Crime Detection and Prevention (ICDP 2016) - Madrid, Spain (23-25 Nov. 2016)] 7th International Conference on Imaging for Crime Detection and Prevention (ICDP 2016) - Person reidentification using omnidirectional cameras
摘要： This study proposes a bodyprint extraction method for people re-identi?cation. Bodyprints are obtained using omnidirectional cameras, knowing the camera model of the ?sheye lens of the camera. These cameras are widely used in surveillance applications since one camera can cover a large area. The proposed method is completely automatic. The results on a database of 31 samples belonging to 5 different persons show a high detection rate of an individual in different locations of the scenario, with different illumination and orientation. Potential applications include tracking suspicious people with networks of non-overlapping cameras or detecting lost people or children in malls or public spaces.
关键词： computer vision,bodyprints,?sheye lenses,omnidirectional,cameras,re-identi?cation
更新于2025-09-09 09:28:46
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Association between multifocal soft contact lens decentration and visual performance
摘要： Purpose: The aim of this study was to assess the association between decentration of several commercial multifocal soft contact lenses (MFCLs) and various objective and subjective visual performance variables in presbyopic and non-presbyopic participants. Materials and methods: All presbyopic (age >40 years, near add ≥+1.25 D) and non-presbyopic (age ≥18 years, no near add requirements, spherical equivalent ≤-0.50 D) participants were each fitted bilaterally with six and two MFCLs (test lens), respectively, and with one single vision lens (control lens). Lens decentration, ie, the x- and y-differences between the contact lens and pupil centers, was objectively determined. Third-order aberrations were measured and compared. Visual performance (high- and low-contrast acuities and several subjective variables) was analyzed for any associations (Pearson’s correlation, r) with MFCL decentration. Results: A total of 17 presbyopic (55.1±6.9 years) and eight non-presbyopic (31.0±3.3 years) participants completed the study. All lenses displayed a temporal–inferior decentration (x=-0.36±0.29 mm, y=-0.28±0.28 mm, mean ± SD). Compared to the control, a significant inferior decentration was found for the Proclear? MFCL Near lens in both groups (ypresbyopic =-0.26 mm, ynon-presbyopic =-0.70 mm) and for the Proclear? MFCL Distance lens in the non-presbyopic group (ynon-presbyopic =-0.69 mm). In both groups, lens-induced vertical coma (C(3, -1)) was, by at least tenfold, significantly more positive for the Proclear? MFCL Distance lens and significantly more negative for the Proclear? MFCL Near lens. In the presbyopic group, the correlation of total MFCL decentration with vision variables was weak (r<|0.191|). Conversely, a moderate but significant correlation with total MFCL decentration was found in the non-presbyopic group for most of the vision variables, indicating a decrease in vision as decentration increased. Conclusion: Certain MFCLs decentered more than others; the same lens designs also induced significant amounts of third-order aberrations. An association between MFCL decentration and seven out of nine vision variables was found in the non-presbyopic group, ie, the group where lenses were most decentered, which had larger pupils and lower levels of inherent third-order aberrations.
关键词： vision,higher-order aberrations,multifocal contact lenses,decentration
更新于2025-09-09 09:28:46
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Patient-reported outcomes of multifocal and accommodating intraocular lenses: analysis of 117 patients 2–10 years after surgery
摘要： The purpose of this study was to determine the satisfaction levels of patients at least 2 years after cataract surgery implantation with bilateral accommodating or bilateral multifocal intraocular lenses (IOLs) and to determine the relative rate of spectacle independence and adverse symptoms in that same time frame. Design: Patient questionnaire administered in a single-center private practice at least 2 years after cataract surgery with presbyopia-correcting IOL implantation. Methods: Patients who had undergone uncomplicated cataract surgery with an accommodating or multifocal IOL implant were eligible for inclusion. Patients with visually significant non-IOL-related postoperative morbidity were excluded. Patients with astigmatism or residual refractive error were not excluded. The main outcome measure was patient satisfaction at least 2 years after IOL implantation. Results: Sixty-eight patients who received accommodating lenses and 49 patients who received multifocal lenses completed the questionnaire. The mean age of all patients was 75.7 years at the time of survey; the mean number of years since cataract surgery was 5.4 years. Overall, there were no significant differences between the two groups or within each group between the different lenses used. About 90% of patients in each group were “very satisfied” or “somewhat satisfied” with their vision at least 2 years after the initial surgery. Conversely, only one in eleven patients found his vision to be worse than expected. Conclusions: The majority of patients who received either accommodating or multifocal IOLs remain satisfied with their lens of choice more than 5 years after the original surgery. Glare and halos remain more noticeable in patients who received multifocal lenses.
关键词： accommodating IOLs,presbyopia,Tecnis,satisfaction,intraocular lenses,crystalens,ReSTOR,patient-reported satisfaction,multifocal IOLs,glasses
更新于2025-09-04 15:30:14
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The impact of a hyaluronic acid-grafted layer on the surface properties of model silicone hydrogel contact lenses
摘要： The introduction of high oxygen transmissibility silicone hydrogel lenses ameliorated hypoxia-related complications, making them the most prescribed type of contact lens. Despite the progress made over the last two decades to improve their clinical performance, symptoms of ocular dryness and discomfort and a variety of adverse clinical events are still reported. Consequently, the rate of contact lens wear discontinuation has not been appreciably diminished by their introduction. Aiming to improve the interfacial interactions of silicone hydrogel contact lenses with the ocular surface, a biomimetic layer of the hydrophilic glycosaminoglycan hyaluronic acid (HA) (100 kDa), was covalently attached to the surface of model poly(2-hydroxyethyl methacrylate-co-3-methacryloxypropyl-tris-(trimethylsiloxy)silane) (pHEMA-co-TRIS) silicone hydrogel materials via UV-induced thiol-ene “click” chemistry. The surface structural changes after each modification step were studied by FTIR-ATR and XPS. Successful grafting of a homogenous HA layer to the surface of the model silicone hydrogels was confirmed by the consistent appearance of N (1s) and the significant decrease of the Si (2p) peaks, as determined by the low-resolution angle-resolved XPS. The HA-grafted surfaces demonstrated reduced contact angles, dehydration rate and nonspecific deposition of lysozyme and albumin, while maintaining their optical transparency (>90%). In vitro studies demonstrated that the HA-grafted pHEMA-co-TRIS materials did not show any toxicity to human corneal epithelial cells. These results suggest that surface immobilization of HA via thiol-ene “click” chemistry can be used as a promising surface treatment for silicone hydrogel contact lenses.
关键词： surface modification,dehydration,contact lenses,hyaluronic acid,MTT assay,thiol-ene chemistry,protein deposition,Silicone hydrogel
更新于2025-09-04 15:30:14
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Surgical management of intraocular lens dislocations
摘要： Purpose: To report and compare the surgical, visual, and anatomical outcomes following treatment of dislocated intraocular lenses (IOLs). Methods: The medical records of 28 eyes of 28 patients were evaluated. Age, gender, pre-and postoperative best-corrected visual acuity (BCVA), surgical methods, and complications were recorded. Results: Pre-and postoperative BCVA ranged from counting fingers to 20/32 and from counting fingers to 20/25, respectively. Late-onset dislocations were the most frequently observed complication. The most frequent surgical method was IOL repositioning in 15 of 28 patients, followed by IOL exchange in 11 patients, and IOL removal in 2 patients. Only 1 patient required surgical re-intervention with IOL capture. Conclusions: Visual acuity improved following the use of either IOL repositioning or IOL exchange. No superiority of one method over the other was observed. In the present retrospective case series, management of dislocated IOLs with repositioning or exchange of the primary implant conferred comparable surgical and visual outcomes.
关键词： Intraocular/methods,Visual acuity/physiology,Lenses intraocular,Lens implantation
更新于2025-09-04 15:30:14