Two patients developed corneal ectasia after photorefractive keratectomy (PRK). Case 1 had evidence of early keratoconus preoperatively, with manifest refractions of -4.00 +2.50 x 160 (20/20) in the right eye and -7.00 +3.00 x 180 (20/30) in the left eye; thin corneas (472 microm and 441 microm, respectively); and inferior paracentral steepening in the right eye and central steepening in the le...

The management of corneal ectasia is evolving, with intrastromal corneal ring segments playing an important role in delaying or eliminating the need for penetrating keratoplasty. This paper describes a modification in the implantation technique of intrastromal corneal ring segments that allows for coupling of the two segments with suture, affording more structural support.

PURPOSE To report a case of corneal ectasia following hyperopic laser in situ keratomileusis in a patient who had previous laser thermal keratoplasty. METHODS Case report. RESULTS We report a case of a 66-year-old emmetropic man initially presented with complaint of difficulty reading without correction. Laser thermal keratoplasty (LTK) was performed on the non-dominant right eye, resulting...

PURPOSE To determine the changes in corneal thickness over time after corneal collagen crosslinking (CXL) for keratoconus and corneal ectasia. SETTING Cornea and refractive surgery subspecialty practice. DESIGN Prospective randomized controlled clinical trial. METHODS Corneal thickness at the apex, thinnest point, and pupil center were measured using Scheimpflug imaging (Pentacam) at base...

OBJECTIVES A study is made on the incidence of corneal ectasia after laser in situ keratomileusis (LASIK) in patients with large differences in mean keratometry (MK) readings between both eyes (OU). Visual outcomes were also evaluated. METHODS The medical records of 164,603 patients (315,259 eyes) who underwent LASIK from January 2003 to December 2011 were reviewed in order to identify patien...

Corneal hysteresis (CH) is a parameter which measures the viscoelastic behaviour of the cornea, indicating its biomechanical integrity1. Some clinical conditions such as keratoconus, Fuchs corneal dystrophy, high myopia, glaucoma and corneal refractive surgery, may induce changes in corneal biomechanical properties, leading to a decrease in CH2-6. Astigmatism, a refractive error related to corn...

Corneal collagen cross-linking with riboflavin and UVA light is a new therapeutic method for increase the biomechanical stability of the cornea through induction of new additional links between collagen fibers. The aim of this paper is to show the mechanism of action of this therapeutically method in different corneal diseases, for which this method can be applied: corneal ectasia, bullous kera...

Several surgical strategies have been proposed to improve visual function in patients with keratoconus who become contact lens intolerant1,2. In mild-tomoderate keratoconus, when the central cornea remains clear, intrastromal corneal ring segments (ICRS), and phakic intraocular lenses (PIOLs) may provide enough BSCVA, and sometimes uncorrected visual acuity (UCVA), to postpone and sometimes avo...

INTRODUCTION Apical protrusion in the central 4-mm ring in the Scheimflug imaging (Pentacam), both for the anterior and posterior floats as well as Corneal Hysteresis and Corneal Resistance Factor by Ocular Response Analyzer (ORA), generally are considered important predictors for post-Lasik ectasia. The aim of this work was to find out if there is a statistically significant correlation betwee...