A simple, non-invasive technique has been developed for assessment of the stability of the pre-corneal tear film. Changes are observed in the reflection of a grid pattern from the tear film surface. Breaks in the tear film appear as random discontinuities in the grid image. Using this non-invasive technique the stability of the pre-corneal tear film was assessed in nine normal subjects and twelve established dry-eye patients. The non-invasive tear film break-up time (NIBUT) of the dry-eye patients was on average only 25% to 32% of normal values. The non-invasive technique provides an alternative approach to diagnosing non-wetting disorders as well as a means of evaluating the efficacy of artificial tear solutions.

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Non-invasive tear film break-up time (NIBUT) was measured in nine normal subjects to investigate the effect of fluorescein instillation of tear film stability. It was found that fluorescein instillation reduced the tear film stability in the treated group, compared with the control group (P less than 0.05). It is, therefore likely that the tear film stability may be greater than had hitherto been suggested by the fluorescein method.

This study has shown clearly that new Etafilcon A lenses do not exhibit significant changes in wettability during the initial four hour wearing period. Pre-treatment of such lenses with a polymeric surfactant results in wetting of the lenses due to the adsorption of surfactant. The surfactant is retained by the lens for at least eight hours of wear, resulting in significant improvements in subjective comfort, especially over the first 30 minutes of wear.

Nanoparticles assembled with poly(styrene-maleic acid) copolymers, identified in the literature as Lipodisq, SMALPs or Native Nanodisc, are routinely used as membrane mimetics to stabilise protein structures in their native conformation. To date, transmembrane proteins of varying complexity (up to 8 beta strands or 48 alpha helices) and of a range of molecular weights (from 27 kDa up to 500 kDa) have been incorporated into this particle system for structural and functional studies. SMA and related amphipathic polymers have become versatile components of the biochemist's tool kit for the stabilisation, extraction and structural characterization of membrane proteins by techniques including cryo-EM and X-ray crystallography. Lipodisq formation does not require the use of conventional detergents and thus avoids their associated detrimental consequences. Here the development of this technology, from its fundamental concept and design to the diverse range of experimental methodologies to which it can now be applied, will be reviewed.