Fluids of the ocular surface: concepts, functions and physics.

General adoption of the ocular surface (OS) concept has advanced the therapy of the external eye. Fresh physical findings have prompted new concepts; examples taken from each section of the text are: (i) ever-present lipid sealant bridges the palpebral fissure capping the three-dimensional 'OS' sac. The muco-aqueous pool (MAP) is thus enclosed, secluded from atmosphere, evaporation mitigated.

A new look at lubrication of the ocular surface: fluid mechanics behind the blinking eyelids.

The concept of the dacruon was presented by the author in this journal in July 2007. Dacruon, defined as "the body of unshed fluid, constantly occupying the ocular surface sac [OSS], comprising the mucoaqueous pool [MAP] and its covering lipid sealant," prompts a fresh consideration of OSS lubrication. The author notes scientific agreement that in the preocular, interpalpebral OSS (the menisco-optical domain), the mucous gel of the MAP adheres to subjacent bulbar epithelium.

Another way to think of tears: blood, sweat, and... "dacruon".

Eugene Wolff's 1946 concept of an interpalpebral, trilaminar, preocular tear film does not sit comfortably with more recent scientific observations. A film so defined could exist only in the interblink phase and would exclude unshed retropalpebral fluid. A modern, evidence-based, clinically relevant model is needed, one that includes retropalpebral and meniscal fluids and is applicable throughout the blink cycle.

Blink-related microtrauma: when the ocular surface harms itself.

Superior limbic keratoconjunctivitis results mechanically from blinking under prolonged unphysiological conditions. The pathogenic process is known as blink-related microtrauma. This review aimed to explore the validity of a general theory that besides superior limbic keratoconjunctivitis, there may be other diseases of the ocular surface arising from mechanical microtrauma.