OBJECTIVES The aim of this study was to measure tear film surface quality (TFSQ) using dynamic high-speed videokeratoscopy during short-term (8 hrs) use of rigid and soft contact lenses. METHODS A group of 14 subjects wore 3 different types of contact lenses on 3 different nonconsecutive days (order randomized) in 1 eye only. The subjects were screened to exclude those with dry eye. The lense...

PURPOSE To evaluate the effect of soft contact lens type on the in vivo tear film surface quality (TFSQ) on daily disposable lenses and to establish whether two recently developed techniques for noninvasive measurement of TFSQ can distinguish between different contact lens types. METHODS Thirteen subjects wearing four different types of daily soft contact lenses participated in the study. Dyn...

PURPOSE A method to measure the tear film beneath a soft contact lens, referred to as post-lens tear thickness (PLTT), would have many applications to contact lens research. In this study a noninvasive technique for measuring the PLTT is presented. METHODS The feasibility of measuring the tear layer by optical pachometry was first assessed using a model eye. The baseline corneal thickness (B)...

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...

The mechanics governing the fit of a soft contact lens on the eye are examined through the development of a finite element analysis model. A linearly elastic lens is placed on a rigid eye with a lubricating viscoelastic tear layer. The mechanics of fit are described in terms of the pressure distribution through the tear layer, the contact pressure at the lens/tear interface, the tear film thick...

Six fungal species (Fusarium sp, Exophiala jeanselmei, Penicillium spp, Aspergillus niger, Paecilomyces spp, and Alternaria spp) were used to inoculate soft contact lenses. Four types of soft lenses were used: high-water (58%) and low-water (38%) content lenses and lenses that were unworn or worn for 1 day. The fungi displayed a range of macroscopic and microscopic features that allowed differe...