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Our aim was to examine secondary image formation in the anterior segment caused by peripheral light focusing (PLF) in the human cornea, and in particular the crystalline lens. Non-sequential ray-tracing (OptiCAD) was applied to an anatomically based human eye model, which incorporates a gradient index crystalline lens. For analysis of the limbal effect, we(More)
The formation of a pterygium is modelled using a population balance model of corneal and limbal epithelial production. Scattered light incident at the temporal limbus is focused at the nasal limbus with a peak intensity > or = 20 times. We hypothesize that this causes a focal alteration of corneal epithelial stem cells (which play a role in maintaining a(More)
PURPOSE Peripheral light-focusing (PLF) is an occult form of ultraviolet radiation (UVR) hazardous to the human eye. In PLF, obliquely incident light is refracted from the peripheral cornea to concentrated sites inside the anterior segment. In the current study, the directionality of this phenomenon for UVR and whether PLF is established in outdoor settings(More)
PURPOSE To characterize peripheral light focusing of oblique off-axis light in the edge-glare phenomenon associated with pseudophakic dysphotopsia. SETTING Department of Ophthalmology, Prince of Wales Hospital, The University of New South Wales, Sydney, Australia. METHODS Nonsequential optical ray-tracing (OptiCAD) was performed on a model pseudophakic(More)
The wound healing response of the cat corneal epithelium was examined to provide information on the effect of extended wear contact lenses on epithelial integrity. During the wounding procedure, a loss of epithelial adhesion in the lens wearing eye relative to the control eye was noted. This indicates a loss of epithelium-to-basement membrane adhesion which(More)
This study presents a computational model of the growth of the normal human lens and the induction of spoke-like cortical cataract in the aging lens. The anterior lens is modelled as a 2-D disk with a circumferential germinative zone. Lens cortical fibre cells in the same generation cover the surface in three identical 120 deg growth wedge-shaped sectors,(More)
Rohon-Beard mechanosensory neurons (RBs), neural crest cells, and neurogenic placodes arise at the border of the neural- and non-neural ectoderm during anamniote vertebrate development. Neural crest cells require BMP expressing non-neural ectoderm for their induction. To determine if epidermal ectoderm-derived BMP signaling is also involved in the induction(More)
  • L S Kwok
  • 1984
The macroscopic anterior surface area was calculated for three models of the average human cornea. Two models, a general ellipsoid and a rotational ellipse (rotationally symmetric ellipsoid) gave a surface area of 132 mm2, while a spherical model gave 126 mm2. A general ellipsoidal model having the maximum radius horizontal (with-the-rule corneal(More)
Orthokeratology attempts to reduce myopia by remoulding the corneal shape with contact lenses. A recent resurgence is predicated on new contact lens designs with a prefigured back contact surface and higher oxygen transmissibility. This Clinical Controversy presents an analysis of the risk factors associated with orthokeratology and its suitability for(More)