Role of chloride channels in regulating the volume of acinar cells of the rabbit superior lacrimal gland.

Purpose: To characterize the outward chloride currents (Cl(OR)) in single acinar cells isolated from the rabbit superior lacrimal gland (RSLG) to investigate the hypothesis that Cl(OR) may have a role in regulating the volume of RSLG acini.

Methods: Cl(OR) was characterized by using patch-clamp electrophysiology. Confocal microscopy was used to measure intracellular calcium concentration ([Ca(2+)](i)) and cell volume.

Implementation of evidence-based practice in optometry.

Evidence-based practice in health care requires that treatment decisions be supported by high-quality clinical evidence, preferably involving well-designed large-scale clinical trials of the various treatment options. How does this relate to everyday primary-care optometry? This article provides a background to the emergence of the 'evidence-based' movement and investigates areas where the efficacy of clinical optometry might be improved by an evidence-based approach. It is argued that evidence-based practice is appropriate for all aspects of optometry but it may be most useful in the selection of treatments with topical therapeutic agents and in optometry's growing public health role in the detection and management of sight-threatening disease.

The surface activity of purified ocular mucin at the air-liquid interface and interactions with meibomian lipids.

Purpose: Ocular mucins are thought to contribute to the stability of the tear film by reducing surface tension. The purpose of this study was to compare the effect of different mucins and hyaluronic acid (HA) alone and mixed with meibomian lipids on the surface pressure at an air-liquid interface.

Methods: A Langmuir trough and Wilhelmy balance were used to measure and compare the surface activity of bovine submaxillary gland mucin (BSM), purified BSM, purified bovine ocular mucin and HA, and mixtures of these with meibomian lipids, phosphatidylcholine, and phosphatidylglycerol.

Surface pressure measurements of human tears and individual tear film components indicate that proteins are major contributors to the surface pressure.

Purpose: Tear film stability has been associated with a low surface tension (high surface pressure), which has been attributed to a variety of tear film components. In this study, we examined the contribution of various tear proteins, mucin, and meibomian lipids to the surface pressure of human tears.

Methods: A Langmuir trough was used to measure and compare the surface activities of albumin, lipocalin, beta-lactoglobulin, lactoferrin, lysozyme, secretory IgA, mucin, meibomian lipid, and tears.

The effects of novel amphipathic block copolymers on stabilization of the rat tear film.

Purpose: To determine whether various novel amphipathic polymers could be used to stabilize the tear film of the rat. The rheologic properties of these polymers were examined to investigate whether particular structural or physical characteristics improve the stability of the tear film.

Methods: Amphipathic polymers or particular phospholipids were mixed with a test solution of tears and saline and applied to the clean, dry corneal surface of a rat.

A survey of pediatric visual assessment by optometrists in New South Wales.

Background: The importance of early vision care in the prevention and treatment of amblyopia is clear from an abundance of literature on visual development. Optometrists possess the necessary skills to detect and manage amblyogenic factors and thus have an important role to play in paediatric visual assessment and management. The present study investigates the role that optometrists in New South Wales are taking in paediatric vision care and the methods and strategies used in this role.

The effect of N-acetylcysteine on the microscopic fluid dynamics of rat tears.

BACKGROUND: The classical view of the tear film is of a 10-micron film of aqueous tears, sandwiched between thin layers of lipid and mucus. This has been challenged recently by the revelation that the tear film may be considerably thicker than 10 microns and that dissolved mucus and protein may play a much more important role than simply promoting tear adherence. In particular, the primary role of mucus may be to form a structured aqueous gel that adheres closely to the corneal surface and evens out its irregularities, thus providing a high-quality optical surface.