Emmetropization is dependent on visual feedback and presumably some measure of the optical and image quality of the eye. We investigated the effect of simple alterations to image contrast on eye growth and refractive development. A 1.6 cyc/deg square-wave-grating target was located at the end of a 3.3 cm cone, imaged by a +30 D lens and applied monocularly to the eyes of 8-day-old chicks. Eleve...

This study investigated differences in geometrical properties and optical aberrations between a group of hyperopes and myopes (age-matched 30.3+/-5.2 and 30.5+/-3.8 years old, respectively, and with similar absolute refractive error 3.0+/-2.0 and -3.3+/-2.0, respectively). Axial length (AL) was measured by means of optical biometry, and corneal apical radius of curvature (CR) and asphericity (Q...

by minimizing the total potential energy function and deploying the virtual work principle, a higher-order stiffness matrix is achieved. this new tangent stiffness matrix is used to solve the frame with geometric nonlinear behavior. since authors’ formulation takes into account the higher-order terms of the strain vector, the convergence speed of the solution process will increase. in fact, bot...

PURPOSE To compare the anterior chamber depth (ACD), keratometry (K) and astigmatism measurements taken by IOLMaster and Pentacam HR in normal and high myopic (HM) eyes. DESIGN A prospective observational case series. METHODS Sixty-six normal eyes and 59 HM eyes underwent ACD, keratometry and astigmatism measurements with both devices. Axial length (AL) was measured on IOLMaster. The interd...

The aim of this study was to investigate the association of axial length (AL)/corneal radius of curvature (CRC) ratio (AL/CRC) with spherical equivalent refractive state (SER) in young adults. A total of seventy (n = 70) subjects consisting of 31 males and 39 females participated in this study. Subjects were categorized into emmetropia, hyperopia and myopia using the spherical equivalent refrac...

The purpose of the study was to investigate the correlation between Corneal Visualization Scheimpflug Technology (Corvis ST tonometry: CST) parameters and various other ocular parameters, including intraocular pressure (IOP) with Goldmann applanation tonometry. IOP with Goldmann applanation tonometry (IOP-G), central corneal thickness (CCT), axial length (AL), corneal curvature, and CST paramet...

AIM The OA-1000 (Tomey, Japan) is a new optical biometer, which measures axial length (AL), anterior chamber depth (ACD), and central corneal thickness (CT) utilizing optical interference technology. The aim of this study was to prove the reproducibility which is considered fundamental for other clinical investigations. METHODS 55 healthy volunteers were enrolled in this study. For each measu...

PURPOSE To evaluate the error in the estimation of axial length (AL) with the IOLMaster partial coherence interferometry (PCI) biometer and obtain a correction factor that varies as a function of AL and crystalline lens thickness (LT). METHODS Optical simulations were produced for theoretical eyes using Zemax-EE software. Thirty-three combinations including eleven different AL (from 20mm to 3...

This paper presents an arc-length preserving axial deformation along a B-spline curve based on arc-length parameterization of the axial curve. Space spanned by arc length and rotation minimizing frame on the axis is taken as the embedded space. As in real life, the length of an object’s skeleton usually remains constant when it is axially deformed such as a swimming fish, a swaying tree etc, An...