In this paper we present a new kind of kinoform lenses in which the phase distribution is characterized by the "devil's staircase" function. The focusing properties of these fractal DOEs coined devil's lenses (DLs) are analytically studied and compared with conventional Fresnel kinoform lenses. It is shown that under monochromatic illumination a DL give rise a single fractal focus that axially ...

PURPOSE To evaluate an interferometric method for measuring the thickness of the pre- (PLTF) and postlens tear film (POLTF) in subjects wearing hydrogel contact lenses. The precision and accuracy of measuring postlens tear thickness is compared with a previous method based on optical pachymetry and mechanical measurement of contact lens thickness. METHODS Reflectance spectra (562-1030 nm) fro...

WILLIAM BuTLER, a physician to James VI and I, had a considerable medical reputation in and immediately after his own time. He practised after the impact of Paracelsus on the older medicine, prescribing indeed chemical medicaments in the Paracelsian manner (as was becoming commoner in England1), but before the days of Sydenham and his philosophy. Butler's methods corresponded with his period, f...

An inductive approach to classifying all toric Fano varieties is given. As an application of this technique, we present a classification of the toric Fano threefolds with at worst canonical singularities. Up to isomorphism, there are 674,688 such varieties.

Contact lens intolerance in keratoconus may be due to the formation of a proud nebula at or near the apex of the cone. Excimer laser superficial keratectomy was performed as an outpatients with proud nebulae as treatment patients with proud nebulae as treatment for their contact lens intolerance. The mean period of contact lens wear before the development of intolerance was 13.4 years (range 2 ...

Contact lens-related problems are common and can result in severe sight-threatening complications or contact lens drop out if not addressed properly. We systematically reviewed the most important and the most common contact lens-related complications and their diagnosis, epidemiology, and management according to the literature published in the last 20 years.

Recent technological advances have had a major impact on military aviation. While modern methods of providing visual information via electro-optics/visionics systems have extended the aviator's operational envelope, these devices are becoming increasingly incompatible with spectacle wear. Since close to 22 percent of Army aviators are ametropic (spectacle wearing), alternative means of providin...