An integrated model for keratectasia risk assessment has received much attention over many years. The objective of this article is to propose a more complete, conceptual model by which high risk individuals can be screened, even with no topographic irregularity or corneal thinning. In this model, corneal ectasia results from the fatigue effect of cyclic shear stress and tensile stress, caused b...

PURPOSE Previously, human corneal stromal interlamellar cohesive strength in the horizontal meridian was shown to be twice as strong peripherally as centrally (approximately 2.90 x 10(-1) versus 1.40 x 10(-1) N/mm). In the current study, stromal samples excised from the vertical meridian were studied to determine if meridional differences also exist. Precise knowledge about corneal stromal stru...

photorefractive keratectomy (prk) is a safe and effective surgical keratorefractive technique which is done with the application of mitomycin-c (mmc) in cases of high myopia to prevent the formation of corneal haze this study was conducted to evaluate 3-year visual acuity and quality outcomes of prk-mmc in high myopia. this before-after study was conducted on 20 individuals (40 eyes) with myopi...

purpose: the goal of this study was to compare differences in the mean heterophoria and fusional amplitudes before and after photorefractive keratectomy (prk) for myopia. methods: in a prospective controlled study, myopic patients were treated with aspheric and wavefront-guided (personalized) prk. the manifest refraction, visual acuity, fusional amplitudes and heterophoria were evaluated preope...

purpose: to evaluate topographic corneal changes in relatives of patients with keratoconus (kcn). methods: this study was performed on 300 eyes of 150 relatives of 45 kcn patients. complete slit lamp examination, refraction, and corneal topography was performed on all eyes. the topographic indices for diagnosis of keratoconus was based on rabinowitz criteria. results: the study included 84 (56%...

introduction : the aim of this study is to define the trend of the orthodontists and the surgeons in the borderline class iii patients and assess their satisfaction after the surgery. materials and methods : the study population consisted of 31 patients (16 female and 15 male) with the average age of 21 years, whose final occlusion 2 months after the surgery was perfect. the amount of reverse o...

Purpose. To evaluate high intensity focused ultrasound (HIFU) as an innovation and noninvasive technique to correct presbyopia by altering corneal curvature in the rabbit eye. Methods. Eighteen enucleated rabbit eyes were treated with a prototype HIFU keratoplasty. According to the therapy power, these eyes were divided three groups: group 1 (1 W), group 2 (2 W), and group 3 (3 W). The change i...

purpose: to determine the long-term visual outcomes and complications of penetrating keratoplasty (pk) performed for keratoconus. methods: hospital records of patients with keratoconus who underwent pk at the ophthalmology center of shaheed sadoughi, yazd, iran, during 1992-2003 were reviewed. we studied records of 84 pk procedures in 72 keratoconus patients. data including best corrected visua...