نتایج جستجو برای: corneal optical power

تعداد نتایج: 761214  

Journal: :Optometry and vision science : official publication of the American Academy of Optometry 2008
Dirk De Brouwere Harilaos Ginis George Kymionis Irini Naoumidi Ioannis Pallikaris

PURPOSE Corneal haze is a well-known pathology associated with decreased corneal transparency and increased ocular scattering. Clinically, haze is typically estimated as the amount of backscattered light observed in a slit lamp examination while the small angle forward scattering cannot be directly observed. It was the purpose of this study to demonstrate a single-pass technique to objectively ...

2012
Elena Albè Paolo Vinciguerra

NOVEMBER/DECEMBER 2012 CATARACT & REFRACTIVE SURGERY TODAY EUROPE 1 A ccuracy of biometric calculations and, more important, of refractive results depends on three main factors: preoperative biometric data including axial length, anterior chamber depth, lens thickness, and corneal curvature power variables; power calculation formulas; and quality and accuracy of the IOL. In the past 15 years, s...

Journal: :journal of current ophthalmology 0
مصطفی محمدیان mostafa mohammadian حسن هاشمی hassan hashemi ابراهیم جعفرزاده پور ebrahim jafarzadehpur محمود جباروند mahmoud jabbarvand علی میرزاجانی ali mirzajani عباسعلی یکتا abbasali yekta مهدی خبازخوب

purpose: comparing the optical coherence tomography (oct) pachymetry patterns in keratoconus suspect and normal people methods: thirty-two keratoconus suspects and 36 healthy eyes were selected within the age range of 20-30 yrs. their pachymetry pattern was obtained through oct visante in the minimum thickness spot, upper and lower corneal difference (i-s), lower temporal, and upper nasal thick...

2014

Methods PTK was performed in 73 eyes of 64 patients. Data regarding the demography, indications for PTK, ablation depth, optical zone, keratometry. BCL removal , symptomatic relief, preand postoperative best spectacle-corrected visual acuity (BSCVA), spherical equivalent changes, recurrence and complications were analyzed. The indications for PTK in our study were classified into two categories...

2017
Alireza Baradaran-Rafii Sahba Fekri Mohammad Rezaie Shahram Salehi-Rad Ali Moradi Tahmineh Motevasseli Masumeh Kalantarion

PURPOSE To compare the corneal power measurements obtained using different topographic instruments after myopic photorefractive keratectomy (PRK). METHODS Patients with myopia who were candidates for corneal refractive surgery were sequentially included. Pre-PRK and six months post-PRK corneal powers were measured using Javal manual keratometer, Orbscan II, Galilei, Tomey TMS4, and EyeSys 200...

Journal: :British Journal of Ophthalmology 1989

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شیراز - دانشکده علوم 1390

any change in the refractive index of a laser active medium can lead to serious degradation of beam quality, laser beam modes, laser performance and variation in the intensity distribution. alteration in the refractive index of laser active medium is especially notable in high power lasers. it is clear that in the laser beam production, the pumping agent induces a great amount of heat which...

Abstract: In this paper, we aim to design and propose a novel structure for all-opticalhalf subtractor based on the photonic crystal. The structure includes two optical switches,one power splitter, and one power combiner. The optical switches are made of theresonant rings which use the nonlinear rods for dropping operation. The footprint of thedesigned structure is about...

2015
Hassan Hashemi Mehdi Khabazkhoob Mohammad Hassan Emamian Mohammad Shariati Mohammad Miraftab Abbasali Yekta Hadi Ostadimoghaddam Akbar Fotouhi

PURPOSE To investigate the association between ocular biometrics such as axial length (AL), anterior chamber depth (ACD), lens thickness (LT), vitreous chamber depth (VCD) and corneal power (CP) with different refractive errors. METHODS In a cross-sectional study on the 40 to 64-year-old population of Shahroud, random cluster sampling was performed. Ocular biometrics were measured using the A...

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