Comparison of central corneal thickness measurement by scanning slit topography, infrared, and ultrasound pachymetry in normal and post-LASIK eyes.

Objectives: To compare central corneal thickness (CCT) measurements by scanning slit topography (SST), infrared pachymetry (IRP), and ultrasound pachymetry (USP), and their agreement in normal and post-laser in situ keratomileusis (LASIK) eyes.

Methods: Sixty normal and 35 post-LASIK subjects were recruited. Only one eye from each subject was analyzed.

Relationship between Vision and Visual Perception in Hong Kong Preschoolers.

Purpose: Although superior performance in visual motor and visual perceptual skills of preschool children has been documented in the Chinese population, a normative database is only available for the US population. This study aimed to determine the normative values for these visuomotor and visual perceptual tests for preschool children in the Hong Kong Chinese population and to investigate the effect of fundamental visual functions on visuomotor and visual perceptual skills.

Methods: One hundred seventy-four children from six different kindergartens in Hong Kong were recruited.

Myopia progression in children is linked with reduced foveal mfERG response.

Purpose: To study the changes in retinal electrophysiology in children during myopia progression during a 1-year period.

Methods: Twenty-six children aged from 9 to 13 years were recruited for the global flash multifocal electroretinogram (mfERG) measured at 49% and 96% contrast, in two visits 1 year apart. The amplitudes and implicit times of both direct component (DC) and induced component (IC) measured at these two visits were analyzed and compared.

Myopic children have central reduction in high contrast multifocal ERG response, while adults have paracentral reduction in low contrast response.

Purpose: To compare the retinal function of myopic children and young adults using the multifocal electroretinogram (mfERG).

Methods: Fifty-two children (aged 9-14 years) and 19 young adults (aged 21-28 years) with spherical equivalent refractive errors ranging from plano to -5.50 diopter (D) were recruited.

Temporal interactive response is resistant to cloudy ocular media in the slow double-stimulation multifocal electroretinogram.

Aim: To examine the influence of cloudy media on the slow double-stimulation multifocal electroretinogram (mfERG).

Methods: Slow double-stimulation mfERG responses were measured from 26 subjects with normal ocular health under normal and light scattering conditions (induced using acrylic sheets) (Experiment 1) and another nine cataract patients before and after cataract surgery (Experiment 2). The amplitudes and implicit times of the first (M(1)) and second (M(2)) stimulation were compared under normal and light scattering conditions in Experiment 1 and they were compared under precataract and postcataract surgery in Experiment 2.

Sign-dependent changes in retinal electrical activity with positive and negative defocus in the human eye.

The purpose of this study was to investigate the effect of optical defocus on changes of electrical response as a function of retinal region. Twenty-three subjects (aged 19-25 year) with normal ocular health were recruited for global flash multifocal electroretinogram (mfERG) recordings under control (fully corrected) condition, and short-term positive defocus (+2D and +4D) and negative defocus (-2D and -4D) conditions. The amplitudes and implicit times of direct (DC) and induced (IC) components of mfERG responses were pooled into six concentric rings for analyses.

Effect of inner retinal dysfunction on slow double-stimulation multifocal electroretinogram.

Purpose: This study investigated the retinal adaptive mechanism in inner retinal dysfunction using the slow double-stimulation multifocal electroretinogram (mfERG) paradigm.

Methods: Slow double-stimulation mfERG responses were recorded from 15 eyes of 15 4-month-old Mongolian gerbils in control conditions and after suppression of inner retinal responses with injections of tetrodotoxin (TTX) and N-methyl-d-aspartic acid (NMDA). The stimulation consisted of five video frames: the two initial frames with multifocal flashes were triggered by two independent m-sequences, followed by three dark video frames.

Detection of early functional changes in diabetic retina using slow double-stimulation mfERG paradigm.

Aim Diabetes mellitus (DM) is a systemic disease with insufficient secretion of insulin or poor response to insulin. This typically causes poor control of blood glucose level leading to a range of complications. Early detection of the retinal function alteration in DM is needed.

Impairment of retinal adaptive circuitry in the myopic eye.

Previous studies have proposed that the inner retina is affected in myopes. This study aimed to investigate the changes in adaptive circuitry of the inner retina in myopia, using the global flash multifocal electroretinogram (global flash mfERG) with different levels of contrast (luminance modulation). Fifty-four myopes had global flash mfERG recorded with different contrasts.