The anterior corneal asphericity (Q) with the tangential radius is calculated, and a three-dimensional (3-D) anterior corneal model is constructed. Tangential power maps from Orbscan II are acquired for 66 young adult subjects. The Q-value of each semimeridian in the near-horizontal region is calculated with the tangential radius. Polynomial fitting is used to model the 360-semimeridional varia...

To evaluate the change in the anterior corneal asphericity (ΔQ) comprehensively calculated using the tangential radius (rt ) after LASIK. Forty-two right eyes were evaluated using the Orbscan II corneal topographer. The pre- and postoperative Q-values of the flat principal semimeridians calculated by the sagittal radius were compared to those by the tangential radius. The Q-value of each semime...

PURPOSE To identify proteins differentially expressed between the tear film of keratoconus (KC) patients and control subjects using two dimensional electrophoresis (2-DE) and mass spectrometry-based techniques. METHODS Twenty two patients (44 eyes) diagnosed with bilateral KC and 22 control subjects (44 eyes) were studied in a prospective case-control study. Keratoconus screening programs and...

PURPOSE To investigate normative angle kappa data and to examine whether correlations exist between angle kappa and ocular biometric measurements (e.g., refractive error, axial length) and demographic features in Koreans. METHODS Data from 436 eyes (213 males and 223 females) were analyzed in this study. The angle kappa was measured using Orbscan II. We used ocular biometric measurements, inc...

The aim of this study was to evaluate the long-term safety and efficacy of photorefractive keratectomy (PRK) for patients with myopia and thin corneas. In this retrospective case series, we included 74 eyes of 38 patients with myopia and central corneal thickness (CCT) < 550 µm who underwent PRK and had a mean postoperative follow-up period of four years. The following factors were evaluated: C...

PURPOSE To report a case of laser in situ keratomileusis (LASIK) that used the Intralase femtosecond laser 14 years after radial keratotomy (RK) for residual myopic astigmatism. METHODS A 39 year-old male patient had undergone a bilateral RK operation for myopic correction. The manifest refraction was -1.25 -3.00 x 175 D, with uncorrected visual acuity (UCVA) of 20/50 and best-corrected visua...

OBJECTIVES To determine the effect of hyperopic laser in situ keratomileusis (H-LASIK) on corneal integrity, by investigating relationships between proportionate corneal tissue ablated and refractive outcomes at 3 months. METHODS 18 eyes of 18 subjects treated with H-LASIK by Technolas 217c Excimer Laser were included in the study. Orbscan II Topography System was used to determine corneal vo...

PURPOSE To compare the corneal power measurements obtained using different topographic instruments after myopic photorefractive keratectomy (PRK). METHODS Patients with myopia who were candidates for corneal refractive surgery were sequentially included. Pre-PRK and six months post-PRK corneal powers were measured using Javal manual keratometer, Orbscan II, Galilei, Tomey TMS4, and EyeSys 200...

PURPOSE To compare the outcomes of implantation of 2 models of intrastromal corneal ring segments (ICRS) to manage keratoconus. SETTING Kartal Training and Research Hospital, Istanbul, Turkey. METHODS This study evaluated eyes with keratoconus that had implantation of Keraring ICRS (Group A) or Intacs ICRS (Group B). The corneal tunnels were created mechanically or with a femtosecond laser....

PURPOSE To investigate corneal thickness, curvature, and morphology with the Orbscan Topography System I (Bausch & Lomb, Inc., Salt Lake City, UT) in patients with Marfan syndrome (MFS) and to study MFS with in vivo confocal microscopy. METHODS This prospective, clinical, comparative case series included 60 eyes of 31 patients with MFS and 32 eyes of 17 control subjects. First, biomicroscopic...