We present analytical considerations of "self-mode-locked" operation in a typical vertical external-cavity surface-emitting laser (VECSEL) cavity geometry by means of Kerr lens action in the semiconductor gain chip. We predict Kerr-lens mode-locked operation for both soft- and hard-apertures placed at the optimal intra-cavity positions. These predictions are experimentally verified in a Kerr-le...

OBJECTIVES Since there are increasing numbers of patients with blepharoptosis who have a history of wearing contact lenses, we attempted to estimate the risk of developing ptosis from wearing hard contact lenses. METHODS In an age-matched case-control study that was performed in a hospital in Japan, we compared the rate of hard contact lens users in ptosis cases with that in a control group a...

We present a method to design binary diffractive microlenses with subwavelength structures, based on the finite-difference time-domain method and the genetic algorithm, also accounting for limitations on feature size and aspect ratio imposed by fabrication. The focusing efficiency of the microlens designed by this method is close to that of the convex lens and much higher than that of the binar...

By using theoretical methods and Monte Carlo simulations, this work investigates dense ordered packings and equilibrium phase behavior (from the low-density isotropic fluid regime to the high-density crystalline solid regime) of monodisperse systems of hard convex lens-shaped particles as defined by the volume common to two intersecting congruent spheres. We show that, while the overall similar...

AIMS This study was undertaken to investigate the effects of contact lens disinfecting solutions on strains of Acanthamoeba from the United Kingdom and southern Africa and to compare the results with those of other researchers. No information was previously available for southern African isolates. METHODS 11 contact lens solutions were tested on cysts of 10 strains of Acanthamoeba. RESULTS ...

Recovery of corneal sensitivity was determined in hard contact lens wearers 2, 4, 6, 12, and 24 hr after removing the lenses. The extent of recovery was shown by the statistical similarity of the threshold values for the contact lens group and the thresholds of a group of subjects who had never worn contact lenses. Consideration of the time course of recovery and of the thermal modality of the ...

Contact lens migration into the upper lid is a rare complication of wearing a hard contact lens. We present a case in which the only complaint was the cosmetically unacceptable appearance of a lump in the upper lid. The 76-month duration of the lesion is, we believe, the longest so far described. The histology and possible natural history of the cyst are also discussed.

The impact of decreased zone height on the focal properties of hard X-ray Bragg-Fresnel zone plates has been studied by numerical simulation. Decreased zone height allows for smaller zone widths and, although the efficiency of the lens is decreased, the signal-to-background ratio in the focal plane of the lens remains at a comparatively high level. This is distinct from an analogous case of ord...