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Refractive errors

Wei Liu, Xin Ma, Xiao Li, Yi Pan, Fuji Wang, Zhenyuan Jia
Nowadays, due to the advantages of non-contact and high-speed, vision-based pose measurements have been widely used for aircraft performance testing in a wind tunnel. However, usually glass ports are used to protect cameras against the high-speed airflow influence, which will lead to a big measurement error. In this paper, to further improve the vision-based pose measurement accuracy, an imaging model which considers the refraction light of the observation window was proposed. In this method, a nonlinear camera calibration model considering the refraction brought by the wind tunnel observation window, was established first...
December 10, 2018: Sensors
Berna Ayan, Nilay Yuksel, Ahmet Carhan, Berrak Gumuşkaya Ocal, Emine Akcay, Nurullah Cagil, Mehmet Dogan Asik
PURPOSE: To evaluate the role of sex steroid hormone receptors in corneal epithelium in etiopathogenesis of keratoconus (KC). METHODS: Thirty patients with KC who were planned for corneal collagen-crosslinking and 20 patients who were planned for excimer laser for refractive errors included in this study. Corneal epitheliums were curated mechanically during surgeries. Right eyes were evaluated immunohistochemically and left eyes were evaluated by quantitative polymerase chain reaction (qPCR) to investigate estrogenα, estrogenβ, progesterone and androgen receptors...
December 8, 2018: Contact Lens & Anterior Eye: the Journal of the British Contact Lens Association
Maged Maher Salib Roshdy, Sherine Shafik Wahba, Rania Serag Elkitkat, Nermine Said Madkour, Ramy Riad Fikry
Purpose: To evaluate the effect of variable corneal thickness on Pentacam HR diagnostic indices in normal corneas. Methods: Retrospective study was conducted at Al Watany Eye Hospital, Cairo, Egypt. Consecutive 160 eyes of young myopic subjects without KC were evaluated using Pentacam HR (WaveLight Allegro Oculyzer II, Erlangen, Germany). The elevation- and thickness-based indices were recorded. Enrolled corneas were categorized into three groups according to TCT quartiles; group 1 (39 eyes) included corneas with TCT <523  µ m, group 2 (81 eyes) with TCT between 523 and 564  µ m, while group 3 (40 eyes) enrolled TCT >564  µ m...
2018: Journal of Ophthalmology
Jennifer L Y Yip, Tess Bright, Sebastian Ford, Wanjiku Mathenge, Hannah Faal
BACKGROUND: Visual impairment is a global public health problem, with an estimated 285 million affected globally, of which 43% are due to refractive error. A lack of specialist eye care in low and middle-income countries indicates a new model of care would support a task-shifting model and address this urgent need. We describe the features and results of the process evaluation of a national primary eye care (PEC) programme in Rwanda. METHODS: We used the Medical Research Council process evaluation framework to examine the implementation of the PEC programme, and to determine enablers and challenges to implementation...
December 7, 2018: BMC Health Services Research
Paolo Mora, Giacomo Calzetti, Stefania Favilla, Matteo Forlini, Salvatore Tedesco, Purva Date, Viola Tagliavini, Arturo Carta, Rino Frisina, Emilio Pedrotti, Stefano Gandolfi
Purpose: To compare the functional and clinical outcomes of the iris-claw intraocular lens (IOL) placed on the anterior versus posterior surface of the iris. Patients and Methods: A multicenter, retrospective study. Data on eyes that underwent anterior or retropupillary iris-claw IOL implantation because of inadequate capsular support secondary to complicated cataract surgery, trauma, and dislocated/opacified IOLs since January 2015 were analyzed. For study inclusion, evaluation results had to be available in the medical records both preoperatively and at 1 and 12 months after implantation...
2018: Journal of Ophthalmology
Aisha Mohammed Alemam, Mohammed Hamad Aldebasi, Abdulkarem Rehmatullah, Rami Alsaidi, Ishraq Tashkandi
Introduction: Around half of the visually impaired population has uncorrected refractive errors (URE), and myopia constitutes a high proportion of them. URE should be screened and treated early to prevent long-term complications. The aim of this study was to determine the prevalence of myopia among all patients attending a pediatric outpatient clinic at Ohud Hospital in Medina, Saudi Arabia (KSA). Method: This study was conducted using a convenience sample of all patients attending the clinic (1500 patients) aged between 3 and 14 years, and they were enrolled in the study during the period from May 2017 until September 2017...
2018: Journal of Ophthalmology
Valbon Ajazaj, Gazmend Kaçaniku, Minir Asani, Afrim Shabani, Ermal Dida
Introduction: Laser in situ keratomileusis (LASIK), a refractive surgery procedure is being performed in a large number among people with refractive errors. In all the people undergoing the procedure, there is a potential risk to misdiagnose the glaucoma disease due to changes in central corneal thickness (CCT). In subjects who have undergone laser refractive interventions, intraocular tension may be lower and underestimated, and this can lead to later detection of glaucoma. Aim: The objective of this study was to analyze the intraocular pressure (IOP) after LASIK in patients with myopia...
November 2018: Medical Archives
A Smagulova, Z Ahmedyanova
The purpose of the study is a comparative analysis of the efficacy and safety of the Femto LASIK and ReLEx SMILE technologies in correcting myopic astigmatism. Materials and methods: The study included 1212 results of interventions in patients with myopic astigmatism, incl. 721 (59.5%) using ReLEx SMILE technology and 491 (40.5%) Femto LASIK technology. Visionometry and refraction investigation were performed at the time of 3, 6, 9, 12 months after the operation, as well as an analysis of the incidence of complications...
October 2018: Georgian Medical News
Abuzer Gunduz, Ercan Ozsoy, Pamuk Betul Ulucan
PURPOSE: To describe the clinical features of patients with Duane retraction syndrome (DRS) and evaluate the outcomes of surgical approaches based on the characteristics of each patient. METHODS: The records of 38 Caucasian subjects with DRS were retrospectively reviewed. The patients were classified as type I, II, or III based on the Huber Classification. Ten patients underwent unilateral medial rectus (MR) recession due to abnormal head posture (AHP) and/or esotropia...
December 5, 2018: Seminars in Ophthalmology
Hyun Goo Kang, Eun Young Choi, Suk Ho Byeon, Sung Soo Kim, Hyoung Jun Koh, Sung Chul Lee, Min Kim
BACKGROUND/AIMS: To compare the efficacy, anatomical outcomes and complications of intravitreal ranibizumab with those of laser photocoagulation for retinopathy of prematurity (ROP). METHODS: This is a retrospective case series of 314 eyes from 165 infants diagnosed with type I ROP and treated with either laser photocoagulation (161 eyes) or intravitreal ranibizumab (0.25 mg/0.025 mL) injection (153 eyes) between January 2006 and December 2016 in a tertiary referral-based hospital...
December 4, 2018: British Journal of Ophthalmology
Shunsuke Funakoshi, Tomoko Yoshikawa, Yosuke Harada, Taiichiro Chikama, Yoshiaki Kiuchi
Purpose: Optical coherence tomography angiography (OCTA) is a new non-invasive imaging technique that does not require the use of contrast agents and that allows the visualization of the retinal microvasculature in a layer-by-layer manner without bright light. This merit allows us to obtain the fundus image in children. Retinal vessels are typically absent from the center of the fovea, an area known as the foveal avascular zone (FAZ). The purpose of the present case study was to evaluate the FAZ in a nanophthalmic pediatric patient with OCTA...
March 2019: American Journal of Ophthalmology Case Reports
Takehiro Yamashita, Aiko Iwase, Hiroshi Sakai, Hiroto Terasaki, Taiji Sakamoto, Makoto Araie
PURPOSE: To determine the relationships between the axial length (AL), refractive error (RE), and body height (BH) at different ages of a genetically-stable population in Kumejima, Japan. METHODS: Cross-sectional, population-based study. Residents of Kumejima who were ≥ 40-years old were studied. The eligible residents had a thorough ocular examinations including measurements of the AL, RE, and BH. The subjects were divided into decade groups. The relationships between the AL, the RE, and the BH of the different decades were determined...
November 30, 2018: Graefe's Archive for Clinical and Experimental Ophthalmology
Pravda Chaturvedi, Arvind Chauhan, Punit Kumar Singh
PURPOSE: An assessment of variation in Macular Volume and RNFL Thickness in myopes using OCT, and their significance for early diagnosis of Primary Open Angle Glaucoma(POAG). MATERIALS AND METHOD: Total of 122 eyes of 61 Indian Myopic subjects of both sex and various age groups underwent retinal nerve fiber layer thickness, macular volume in 6mm analysis by Rtvue Avanti SD-OCT, Optovue Technology V6.1.1,after taking due consent from ethical committee. Subjects were divided into two groups based on their refractive error, Group A <6 D and Group B >6D...
September 2018: Oman Journal of Ophthalmology
Sherif Eissa, Nashwa Badr Eldin
OBJECTIVE: We compare the predictability, safety, and efficacy of posterior chamber phakic intraocular lens (PCpIOL) versus small-incision lenticule extraction (SMILE) for correcting myopic anisometropia in amblyopic children. METHODS: A prospective randomized study enrolled 30 children, aged 4-12 years, with unilateral myopic anisometropic amblyopia whose refraction ranged between -5 and -10 diopters (D) and myopic astigmatic error -1 to -6 D. Patients were subdivided into group A for unilateral PCpIOL implantation and implantable collamer lens (Visian ICL/TICL) of V4C design and group B for SMILE procedure...
December 2018: Canadian Journal of Ophthalmology. Journal Canadien D'ophtalmologie
Aoi Matsumura, Atsushi Ueda, Yasuo Nakamura
The conventional acromion marker cluster (AMC) method used to estimate scapular orientation cannot adequately represent complex shoulder movements due to soft tissue artifacts. The regression method may have nonlinear error changes depending on humeral elevation angle and elevation plane. Therefore, we aimed to develop a new method of estimating scapular orientation using curved surface interpolation during various shoulder movements, and to compare its accuracy with conventional and regression methods. Thirteen healthy men were recruited...
November 13, 2018: Journal of Electromyography and Kinesiology
A A Shpak, S V Kostenev, I A Mushkova, M V Korobkova
The effect of significant changes in corneal power after refractive surgery on the parameters of optical coherence tomography (OCT) has not been sufficiently studied. PURPOSE: To study effects of corneal refractive surgery on optical coherence tomography (OCT) measurements in patients with moderate and high myopia. MATERIAL AND METHODS: OCT was performed in 62 patients (62 eyes) with myopia over 4 D before and one month after LASIK. The changes in 14 parameters of the thickness of the retina, ganglion cell-inner plexiform layer (GCIPL) and peripapillary retinal nerve fiber layer (pRNFL) were analyzed...
2018: Vestnik Oftalmologii
S A Malozhen, S V Trufanov, D A Krakhmaleva, E V Sukhanova
PURPOSE: To evaluate the effectiveness and safety of peripheral lamellar keratoplasty (LKP) for treating relapsing pterygium. MATERIAL AND METHODS: The study was conducted in the period of 2007-2017 and included 84 patients (91 eyes) with stage II-IV relapsing pterygium. Best corrected visual acuity (BCVA) before the surgery was in average 0.65±0.28 (0.01 to 1.0). Astigmatism varied from 0.5 to 6.5 D (mean 3.41±2.06). All patients underwent pterygium removal surgery followed by LKP...
2018: Vestnik Oftalmologii
V R Mamikonyan, S V Trufanov, L Yu Tekeeva, S A Malozhen, A M Subbot, A A Fyodorov
PURPOSE: To study the effectiveness of polishing Bowman's membrane with a diamond burr (DBPBM) in the treatment of recurrent corneal erosion syndrome (RCES). MATERIAL AND METHODS: The study included 22 patients (22 eyes) with RCES aged 20-56 years who underwent our original modification of DBPBM. All patients had keratotopography examined, endothelial cell density measured, and optical coherence tomography (OCT) of the cornea taken before and after the procedure...
2018: Vestnik Oftalmologii
Anil Chekuri, Bhubanananda Sahu, Venkata R M Chavali, Marina Voronchikhina, Angel-Soto Hermida, John J Suk, Akhila N Alapati, Dirk-Uwe Bartsch, Raul Ayala-Ramirez, Juan C Zenteno, Astra Dinculescu, Monica M Jablonski, Shyamanga Borooah, Radha Ayyagari
Patients harboring homozygous c.498_499insC mutations in MFRP demonstrate hyperopia, microphthalmia, retinitis pigmentosa, retinal pigment epithelial (RPE) atrophy, variable degrees of foveal edema and optic disc drusen. The disease phenotype is variable however, with some patients maintaining good central vision and cone function till late in the disease. We developed a knock-in mouse model with the c.498_499insC mutation in Mfrp (Mfrp KI/KI) to understand the effects of these mutations in the retina. Our model shares many of the features of human clinical disease including reduced axial length, hyperopia, retinal degeneration, RPE atrophy and decreased electrophysiological responses...
November 30, 2018: Human Gene Therapy
Annemarie Buser, Peter Baumbach, Bettina von Livonius
As an ophthalmologist, it is very important to know whether limited vision is caused by refractive problems or whether there is another pathology behind it. That's why refraction plays a key role at the beginning of every eye examination. Therefore, it is important to know the basic principles of optics. When fitting spherical and cylindrical lenses, it is interesting to know which properties the respective lenses have. One should also be aware of the optical paths and refraction laws when fitting spectacle lenses and prisms...
November 28, 2018: Klinische Monatsblätter Für Augenheilkunde
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