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higher-order aberrations

Shigeyuki Morishita, Masaki Mukai, Kazu Suenaga, Hidetaka Sawada
Transmission electron microscopy using low-energy electrons would be very useful for atomic resolution imaging of specimens that would be damaged at higher energies. However, the resolution at low voltages is degraded because of geometrical and chromatic aberrations. In the present study, we diminish the effect of these aberrations by using a delta-type corrector and a monochromator. The dominant residual aberration in a delta-type corrector, which is the sixth-order three-lobe aberration, is counterbalanced by other threefold aberrations...
October 7, 2016: Physical Review Letters
Natasha Kishore Pahuja, Rohit Shetty, Abhijit Sinha Roy, Maithil Mukesh Thakkar, Chaitra Jayadev, Rudy Mma Nuijts, Harsha Nagaraja
PURPOSE: To evaluate the outcomes of corneal laser ablation with Q factor modification for vision correction in patients with progressive keratoconus. METHODS: In this prospective study, 50 eyes of 50 patients were divided into two groups based on Q factor (>-1 in Group I and ≤-1 in Group II). All patients underwent a detailed ophthalmic examination including uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), subjective acceptance and corneal topography using the Pentacam...
October 21, 2016: Current Eye Research
Renfeng Xu, Huachun Wang, Feng Jiang, Chunyan Xue, Zhenping Huang, Arthur Bradley
PURPOSE: We hypothesize that the typically narrower palpebral apertures of East Asian eyes in combination with the narrowing of this aperture during down-gaze combine to reduce light levels and image contrast in the inferior retina during near work, thus creating peripheral deprivation in these eyes that could generate deprivation myopia in children culturally encouraged to perform near work. METHODS: We photographed the right eyes of 53 Chinese children during down-gaze (from 10 to 40 degrees) from the fixation point and the primary gaze position...
October 18, 2016: Optometry and Vision Science: Official Publication of the American Academy of Optometry
Qing Wang, Wenwen Liu, Yili Wu, Yan Ma, Guiqiu Zhao
BACKGROUND: An investigation was carried out to find the distribution of central corneal thickness (CCT) and the association between CCT and ocular factors in a cohort of myopic Chinese adults who underwent laser refractive surgery. METHODS: Medical records of 1,190 subjects (754 males) aged from 18 to 44 years (21.5 ± 3.5 years for males and 24.9 ± 5.5 years for females) undergoing myopic refractive surgery were filtered and analysed. Each parameter was stratified by gender and eye, respectively...
October 18, 2016: Clinical & Experimental Optometry: Journal of the Australian Optometrical Association
Jack R Staunton, Wilfred Vieira, King Leung Fung, Ross Lake, Alexus Devine, Kandice Tanner
One of the hallmarks of the malignant transformation of epithelial tissue is the modulation of stromal components of the microenvironment. In particular, aberrant extracellular matrix (ECM) remodeling and stiffening enhances tumor growth and survival and promotes metastasis. Type I collagen is one of the major ECM components. It serves as a scaffold protein in the stroma contributing to the tissue's mechanical properties, imparting tensile strength and rigidity to tissues such as those of the skin, tendons, and lungs...
September 2016: Cellular and Molecular Bioengineering
Negin Amirshekarizadeh, Hassan Hashemi, Ebrahim Jafarzadehpur, Ali Mirzajani, Abbasali Yekta, Mehdi Khabazkhoob
PURPOSE: To determine the effect of cyclopentolate, tropicamide, and artificial tear drops on higher-order aberrations (HOAs) in normal eyes with OPD-Scan III (Nidek Inc., Tokyo, Japan). METHODS: In this study, 189 eyes of individuals aged 20 to 35 years were selected as samples. Inclusion criteria were a corrected visual acuity of 20/20 or better, a minimum size of about 5 mm for the pupil in the dark, hyperopia and myopia less than 5 D, and astigmatism less than 2 D...
September 30, 2016: Eye & Contact Lens
Koray Gumus, Aysegul Guven, Miray Altnkaynak, Merve Keskin
OBJECTIVES: The aim of this study was to compare different measurement tools and parameters, including a new computer-assisted image processing technique for the quantitative analysis of the percentage of pterygium on the corneal surface, horizontal/vertical lengths obtained using slitlamp beam and surgical compass. METHODS: A total of 21 pterygia of 17 patients were included in the study. The pterygia were measured by three different methods: a slitlamp beam, a surgical compass, and a new computer-assisted image processing method...
September 30, 2016: Eye & Contact Lens
Kazuo Tsubota, Norihiko Yokoi, Jun Shimazaki, Hitoshi Watanabe, Murat Dogru, Masakazu Yamada, Shigeru Kinoshita, Hyo-Myung Kim, Hung-Won Tchah, Joon Young Hyon, Kyung-Chul Yoon, Kyoung Yul Seo, Xuguang Sun, Wei Chen, Lingyi Liang, Li Mingwu, Zuguo Liu
For the last 20 years, a great amount of evidence has accumulated through epidemiological studies that most of the dry eye disease encountered in daily life, especially in video display terminal (VDT) workers, involves short tear film breakup time (TFBUT) type dry eye, a category characterized by severe symptoms but minimal clinical signs. An unstable tear film also affects the visual function, possibly due to the increase of higher order aberrations. Based on the change in the understanding of the types, symptoms, and signs of dry eye disease, the Asia Dry Eye Society agreed to the following definition of dry eye: "Dry eye is a multifactorial disease characterized by unstable tear film causing a variety of symptoms and/or visual impairment, potentially accompanied by ocular surface damage...
October 7, 2016: Ocular Surface
Manli Liu, Jianchao Wang, Wen Zhong, Danyang Wang, Yugui Zhou, Quan Liu
PURPOSE: To evaluate the clinical results of suction loss in eyes during small incision lenticule extraction (SMILE). METHODS: This prospective paired-eye case study enrolled 8,490 eyes of 4,296 patients, of which 35 eyes experienced suction loss during the SMILE procedure while being treated for myopia or myopic astigmatism. The eyes with suction loss were re-treated with SMILE, femtosecond laser-assisted LASIK (FS-LASIK), or pseudo SMILE, and the fellow eyes were treated with SMILE...
October 1, 2016: Journal of Refractive Surgery
Hassan Hashemi, Reza Ghaffari, Mohammad Miraftab, Soheila Asgari
PURPOSE: To compare 18-month outcomes between femtosecond laser-assisted LASIK (femto-LASIK) and photorefractive keratectomy with mitomycin-C (PRK-MMC) for myopia of more than 7.0 D in terms of visual acuity and quality. METHODS: In this comparative nonrandomized clinical trial, 60 eyes from 30 patients (30 eyes in each group) were enrolled. The two procedures were compared in terms of 18-month changes in uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction spherical equivalent, ocular and corneal higher order aberrations (HOAs), and contrast sensitivity (CS)...
October 3, 2016: International Ophthalmology
Arun Kumar Jain, Chintan Malhotra, Anand Pasari, Pawan Kumar, Majid Moshirfar
PURPOSE: To compare the outcomes of topography-guided and wavefront-optimized treatment in patients having laser in situ keratomileusis (LASIK) for myopia. SETTING: Advanced Eye Centre, Post Graduate Institute of Medical Education and Research, Chandigarh, India. DESIGN: Prospective contralateral-eye case study. METHODS: Patients had topography-guided LASIK in 1 eye and wavefront-optimized LASIK in the contralateral eye using the Customized Refractive Surgery Master software and Mel 80 excimer laser...
September 2016: Journal of Cataract and Refractive Surgery
Melanie Spitzwieser, Christine Pirker, Bettina Koblmüller, Georg Pfeiler, Stefan Hacker, Walter Berger, Petra Heffeter, Margit Cichna-Markl
Overexpression of ABCB1, ABCC1 and ABCG2 in tumor tissues is considered a major cause of limited efficacy of anticancer drugs. Gene expression of ABC transporters is regulated by multiple mechanisms, including changes in the DNA methylation status. Most of the studies published so far only report promoter methylation levels for either ABCB1 or ABCG2, and data on the methylation status for ABCC1 are scarce. Thus, we determined the promoter methylation patterns of ABCB1, ABCC1 and ABCG2 in 19 human cancer cell lines...
September 28, 2016: Oncotarget
Soo Hwan Kim, Gi Jin Kim, Tsukuru Umemura, Seung Gwan Lee, Kyung Jin Cho
In order to investigate whether plasma microRNA-33a (miR-33a) can be a biomarker for the early detection of atherosclerosis and to reexamine the assumption that miR-33a represses the expression of ABCA1, we compared the expression levels of miR-33a and ATP-binding cassette A1 (ABCA1) using human plasma and supernatants of macrophage cultured media. We first separated ample number of plasma samples from left-over whole blood samples based on the criteria for normal or dyslipidemia, and stored them at -20 °C until use...
September 23, 2016: Molecular Biology Reports
Chuncheng Gong, Kuang He, Gun-Do Lee, Qu Chen, Alex W Robertson, Euijoon Yoon, Suklyun Hong, Jamie H Warner
An in situ heating holder inside an aberration-corrected transmission electron microscope (AC-TEM) is used to investigate the real-time atomic level dynamics associated with heterogeneous nucleation and growth of graphene from Au nanoparticle seeds. Heating monolayer graphene to an elevated temperature of 800 °C removes the majority of amorphous carbon adsorbates and leaves a clean surface. The aggregation of Au impurity atoms into nanoparticle clusters that are bound to the surface of monolayer graphene causes nucleation of secondary graphene layers from carbon feedstock present within the microscope chamber...
September 19, 2016: ACS Nano
Fatemeh Alipour, Firoozeh Rahimi, Mohammad Naser Hashemian, Zahra Ajdarkosh, Ramak Roohipoor, Masoumeh Mohebi
PURPOSE: To evaluate the feasibility and efficacy of mini-scleral design (MSD) contact lenses to treat keratoconus patients who were unsatisfied with the results of corneal inlay. METHODS: In this prospective interventional case series, 9 eyes of 6 keratoconus patients who were unsatisfied with the results of corneal inlay were fitted with MSD contact lenses. Demographic data, uncorrected visual acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), and higher order aberrations (HOAs) were evaluated before contact lens fitting...
July 2016: Journal of Ophthalmic & Vision Research
Elvin Yildiz, Meltem Tunca Toklu, Ece Turan Vural, Nursal Melda Yenerel, Handan Bardak, Esra Turkseven Kumral, Yavuz Bardak
PURPOSE: To evaluate the accommodative response to different accommodative stimulus and to determine the changes in ocular higher-order aberrations with accommodation in keratoconus patients fitted with mini scleral lenses. MATERIAL AND METHODS: The study included 15 keratoconus patients wearing mini scleral lenses (Misa Scleral Lens-Microlens, Arnhem, the Netherlands) and 15 keratoconus patients wearing rigid gas permeable lenses. Hartmannn Shack aberrometer (IRX-3; Imagine Eyes, Orsay, France) was used for the evaluation of accommodation...
September 7, 2016: Eye & Contact Lens
David Donate, Rozenn Thaëron
PURPOSE: To compare the visual outcomes with energy close to the plasma threshold and energy at the standard set-up in small incision lenticule extraction (SMILE). METHODS: This retrospective, non-randomized, consecutive clinical case series included 486 eyes of 243 patients who underwent SMILE and were subdivided into two groups depending on the laser energy settings: the standard energy group (164 eyes) using a laser cut energy index of 36 (180 nJ), and the plasma threshold group (322 eyes) using a cut energy index of 20 (100 nJ, close to plasma threshold)...
August 1, 2016: Journal of Refractive Surgery
Yusuf Yildirim, Onur Olcucu, Cengiz Alagoz, Abdurrahman Basci, Alper Agca, Dilek Yasa, Engin Bilge Ozgurhan, Ahmet Demirok
PURPOSE: To compare the refractive outcomes of small incision lenticule extraction (SMILE) with photorefractive keratectomy (PRK) using an aberration-free ablation profile. METHODS: One eye of patients diagnosed as having myopia for bilateral refractive correction was randomly allocated to either PRK or SMILE. The primary outcome measures included refractive efficacy, predictability, safety, stability, corneal aberrations, and adverse events. Patients were followed up for 1 year postoperatively; postoperative uncorrected distance visual acuity (UDVA), corrected distance visual acuity (CDVA), manifest refraction, and corneal aberrations were recorded and compared with preoperative data...
August 1, 2016: Journal of Refractive Surgery
M Brancewicz, M Itou, Y Sakurai, A Andrejczuk, S Chiba, Y Kayahara, T Inoue, M Nagamine
We present a new planar Ni compound refractive lens for high energy X-rays (116 keV). The lens is composed of identical plano-concave elements with longitudinal parabolic grooves manufactured by a punch technique. In order to increase the lens transmission, the thickness of the single lens at the parabolic groove vertex was reduced to less than 5 μm and the radius of curvature was reduced to about 20 μm. The small radius of curvature allowed us to reduce the number of single elements needed to get the focal length of 3 m to 54 single lenses...
August 2016: Review of Scientific Instruments
Shizuka Koh
Dry eye has been believed to be a chronic, symptomatic ocular surface disease that affects vision in a limited manner, because it is difficult to detect visual or optical changes using standard visual acuity testing. In practice, common visual complaints associated with dry eye include fluctuating vision with blinking, blurred vision, glare, and eye fatigue. This review discusses our past and current understanding of visual disturbances in dry eye and the various tools available for assessing visual function or optical quality...
November 2016: Cornea
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