نتایج جستجو برای: corneal optical power
تعداد نتایج: 761214 فیلتر نتایج به سال:
BACKGROUND The purpose of this study was to evaluate the effect of daily administration of mannitol-enriched sodium hyaluronate ophthalmic solution on the corneal optical properties of subjects wearing low Dk hydrogel (etafilcon A) contact lenses (CLs). METHODS Forty-five subjects wearing etafilcon A CLs daily for more than 6 months were recruited into this pilot study. Fifteen of the subject...
Purpose. To compare the higher-order aberrations (HOAs) due to the anterior and posterior corneal surfaces in patients that underwent either Descemet-stripping-automated-endothelial-keratoplasty (DSAEK) or penetrating keratoplasty (PK) for endothelial dysfunction and age-matched controls. Methods. This retrospective, observational, case series included 28 patients after PK, 30 patients after DS...
PURPOSE To analyze the mechanisms of myopia in Cohen syndrome (Mendelian Inheritance in Man [MIM] no. 216550). METHODS A cross-sectional study of 22 Finnish patients (age range, 2-57 years) with Cohen syndrome, which maps to chromosome 8q22, was undertaken to record cycloplegic refraction, keratometry (corneal power and radius of curvature), biometry (anterior chamber depth [ACD], lens thickn...
PURPOSE To compare 2 optical patient interface designs used for femtosecond laser-assisted cataract surgery. SETTING Optimedica Corp., Santa Clara, California, USA, and Centro Laser, Santo Domingo, Dominican Republic. DESIGN Experimental and clinical studies. METHODS Laser capsulotomy was performed during cataract surgery with a curved contact lens interface (CCL) or a liquid optical imme...
BACKGROUND To evaluate and compare the astigmatism prediction errors taken with the Pentacam measurements, Baylor nomogram, and Barrett formula for toric intraocular lens (IOL) implantation. METHODS Phacoemulsification with toric Precizon IOL implantation was performed in 41 eyes with corneal astigmatism (range, 1 to 5 diopters (D)) determined by IOLMaster and SimK on Pentacam. Preoperative c...
purpose: to describe a novel surgical technique for in vivo limbal stem cell cultivation for reconstruction of corneal epithelium in total limbal stem cell deficiency (lscd). methods: patients suffering from chronic total unilateral lscd due to a chemical injury were sequentially included. one small limbal block (2x1 mm) harvested from contralateral healthy eye sutured over the amniotic membran...
Lensometers and keratometers yield powers along perpendicular meridians even if the principal meridians of the lens and the cornea are oblique. From each such instrument, multiple raw data represented on optical crosses require conversion to determine elementary statistics. Calculations for research decisions need to be authentic. Principles common to meridians generalize formulaic methods for ...
Recent advances in the field of plastic optical corneal prostheses suggest that they have finally moved from the experimental to the clinical field. To some extent this feeling is justified because in the past io years many types of keratoprostheses have been used, improving vision in eyes which would otherwise have remained blind. The numerous publications on this subject and the various model...
Here, we propose an optical filter and an optical power splitter based on two-dimensionalphotonic crystal all circular ring resonators. These structures are made of a square lattice ofsilicon rods with the refractive index n1=3.464 surrounded by air (with refractive indexn2=1). First, we have designed the filter and by using that, we designed a power splitter. Thetransmission efficiency and Qua...
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