In this paper, we present a fast GPU-based algorithm for ray-tracing point-based models, which includes an efficient computation of secondary and shadow rays, contrary to previous work which supported ray-surface intersections for primary rays only. Volumetric effects are added to the models by means of scattered data interpolation in order to combine point-based surface and volume rendering in...

OBJECTIVE To evaluate the accuracy of noncycloplegic refraction compared with cycloplegic refraction in diagnosing refractive error in primary school children in southern Thailand. MATERIAL AND METHOD This is a cross-sectional study. One hundred twenty children aged from 6-13 years who had visual acuity of 20/40 or worse in at least one eye were included. All the children underwent autorefrac...

Background. Optical coherence tomography (OCT) allows quantitative analysis of the anterior segment of the eye with a noncontact examination. The aim of this study is to analyze associations of central corneal thickness (CCT) as measured by OCT with ocular and systemic cardiovascular parameters. Methods. A cross-sectional study of 734 persons was performed in a working age population. Only heal...

Intraocular lens (IOL) is widely used for cataract treatment. Its optical properties are crucial to obtain a good treatment efficacy and thus need be evaluated controlled. In this study, we propose novel method based on coherence tomography (OCT) noncontact accurate in vitro measurement of thic...

Operational and safety issues associated with subsiding sinkholes in karst areas start the definition of fractures joints, causing ground weakness. Conventional geotechnical boreholes geological mapping must be complemented indirect subsurface exploration techniques to detail those structures. This work aims use electrical resistivity tomography (ERT) seismic refraction (SRT) near-surface geoph...

The dielectric with index of refraction n is inserted in the Planck blackbody. The spectral formula for photons in such dielectric medium and the equation for the temperature of photons is derived. The new equation is solved for the constant index of refraction. The photon flow initiates the osmotic pressure of he Debye phonons. The dielectric crystal surface works as the osmotic membrane with ...

PURPOSE After refractive surgery, changes in central ocular surface power are usually less than actual changes in refraction. The aim of this paper was to examine the theoretical changes in the radius of the epithelial-stromal interface and corneal stromal refractive index which could take place to account for some of the empirical findings. METHODS The parameters of an aspheric human eye mod...