PURPOSE To quantify optical and biomechanical properties of the feline cornea before and after photorefractive keratectomy (PRK) and assess the relative contribution of different biological factors to refractive outcome. SETTING Department of Ophthalmology, University of Rochester, Rochester, New York, USA. METHODS Adult cats had 6.0 diopter (D) myopic or 4.0 D hyperopic PRK over 6.0 or 8.0...

Background: To evaluate the agreement in intraocular pressure (IOP) measurements by Ocular Response Analyzer (ORA) and Tono-Pen XL (TXL) with the Goldmann Applanation Tonometer (GAT) and to examine corneal biomechanical properties in aphakic glaucoma patients with a central corneal thickness (CCT) >600 µ. Methods: Thirty-six eyes of aphakic glaucoma patients (group 1) and 40 eyes of normal chil...

PURPOSE To investigate the test-retest variability of and factors associated with the corneal deformation response, and evaluate its impact on IOP measurement. METHODS Forty normal and 140 glaucoma suspect/glaucomatous eyes of 104 individuals were prospectively included for repeated measurements of corneal deformation response by an ultra-high-speed Scheimpflug camera, followed by corneal hys...

Purpose. To thoroughly analyze corneal deformation responses curves obtained by Ocular Response Analyzer (ORA) testing in order to improve subclinical keratoconus detection. Methods. Observational case series of 87 control and 73 subclinical keratoconus eyes. Examination included corneal topography, tomography, and biomechanical testing with ORA. Factor analysis, logistic regression, and receiv...

Purpose To evaluate and compare corneal hysteresis (CH) and corneal resistance factor (CRF) in pellucid marginal degeneration (PMD), keratoconus (KCN), and normal eyes using the Ocular Response Analyzer (ORA). Methods In this retrospective study, corneal biomechanical parameters were measured in patients with PMD (n = 102) and KCN (n = 202) and normal subjects (n = 208) using the ORA. Data, i...

purpose: to compare corneal hysteresis and resistance factor after penetrating keratoplasty (pk) and deep anterior lamellar keratoplasty (dalk) using anwar’s big-bubble technique using the ocular response analyzer. methods: forty-five pk eyes and 23 dalk eyes with keratoconus were compared in terms of corneal hysteresis (ch), corneal resistance factor (crf), goldmann-correlated intraocular pres...

PURPOSE To determine the characteristics and risk factors for occurrence of opaque bubble layer (OBL) during femtosecond laser-assisted flap creation for LASIK. METHODS One hundred ninety-eight eyes of 102 consecutive patients who underwent LASIK flap creation performed with the Alcon WaveLight FS200 laser (Alcon Laboratories, Inc., Fort Worth, TX) were retrospectively analyzed in a cohort st...

Introduction In a broad review, evidence that the corneal biomechanical properties influence the results and outcomes of various ocular measurements and procedures has existed for some time [1,2]. However, assessing the biomechanical properties of corneal tissue in vivo has previously not been possible. With the recent introduction of the Reichert Ocular Response Analyzer (ORA), direct clinical...

PURPOSE Recent studies report that increased corneal edema because of contact lens wear under closed lids is associated with elevated Goldmann intraocular pressure (GAT IOP). We sought to assess whether the impact of postoperative corneal edema on GAT IOP would be similar and to determine the differential effect of different amounts of edema. METHODS The setting is a tertiary level cataract c...