PURPOSE To study the changes in posterior corneal elevation after laser in situ keratomileusis (LASIK) and photorefractive keratectomy (PRK) using Scheimpflug topography with the Pentacam anterior segment imaging system (Oculus, Inc.). SETTING Department of Ophthalmology, Albany Medical Center, and a private clinical practice, Albany, New York, USA. METHODS In this prospective study, 121 co...

purpose: to report the development of cataract after corneal damage by dungle beetle prongs. case report: a 28 year-old man, resident of the village chah setareh, sabzevar, presented complaining of trauma to the right eye with the dangle beetle while motorcycling. slit lamp examination revealed six corneal perforations, hyphema (50% of anterior chamber) percent, iris sphincter rupture, and rupt...

PURPOSE To compare changes of anterior corneal aberration (Pentacam) and ocular aberration (aberrometer, LADARWave) after laser refractive surgery. METHODS Sixty-six eyes underwent laser refractive surgery and were retrospectively reviewed. Anterior corneal aberration and ocular aberration were measured by Pentacam and an aberrometer (LADARWave) respectively. Changes of root mean square (RMS)...

PURPOSE The aim of this study was to determine the agreement between Pentacam HR (Scheimpflug imaging, Oculus) and Orbscan II (scanning slit topography, Bausch and Lomb) in measuring corneal parameters after photorefractive keratectomy (PRK) for hyperopia. METHODS In this prospective cross-sectional study, 38 hyperopic eyes undergoing PRK were examined before refractive surgery and 8 to 10 mo...

Our purpose is to correct digital CCD-recorded Scheimpflug photographs, imaging both the anterior and posterior corneal surface, the anterior chamber, and the anterior eye lens surface for optical distortions. In a ray-tracing algorithm the imaging of the posterior corneal surface in a given Scheimpflug photograph is corrected by applying Snell's law on parallel incident rays entering through t...

PURPOSE To evaluate the impact of differente soft contact lens power in the anterior corneal curvature and regularity in subjects with keratoconus. METHODS Nineteen subjects (30 eyes) with keratoconus were included in the study. Six corneal topographies were taken with Pentacam Eye System over the naked eye and successively with soft lens (Senofilcon A) powers of -3.00, -1.50, 0.00, +1.50 and...

In the optical system of the human eye, total refractive power consists mainly of corneal and lenticular components. Approximately two-thirds of the eye's converging power is at the air–cornea (tear film) interface; one-third is in the lens. Total corneal power is determined by corneal anterior and posterior curvature, corneal thickness, and the corneal refractive indices. Traditionally, anteri...

PURPOSE To identify an optimal customized ablation strategy in the treatment of eyes with secondary irregular astigmatism. METHODS Corneal anterior surface elevation maps of 50 eyes with secondary irregular astigmatism after decentered laser in situ keratomileusis (LASIK) or photorefractive keratectomy (PRK) and 50 virgin eyes were used for customized ablation simulations. Two ablation simula...

purpose: to describe a case with a rare complication of posterior chamber intraocular lens (pc-iol) implantation in a patient who had undergone extracapsular cataract extraction (ecce) two years before case report: a 80-year-old diabetic woman presented with an exposed pc-iol in her left eye with a history of mechanical trauma. slit-lamp examination revealed an extruded pc-iol lied on the anter...