In my chemistry lectures in high school, I learned that water can have three phases: solid, liquid, and vapor. I did not learn of a fourth phase of water until recently when my colleagues Drs. Patrick Simard and Rémy Marcotte-Collard introduced me to this concept. Seconds later, I had a “Eureka!” moment—a sudden, illuminating “Wow” moment of what is potentially occurring in the closed environment of the tear reservoir when scleral lenses are worn.

What Is the Fourth Phase of Water?

This concept of a forth phase of water dates back almost a century, as suggested by Sir William Hardy (www.oxforddnb.com/view/10.1093/ref:odnb/9780198614128.001.0001/odnb-9780198614128-e-33709 ), who studied the molecular physics of films. He was trying to explain an unusually structured phase of water that was not so easy to observe. Subsequently, other authors over the years found evidence for this idea, but it wasn’t proven until recently; with the help of sophisticated tools, Pollack (2013) was able to demonstrate that this state of water does exist. Sir Hardy was right.

According to Dr Pollack’s observations, the fourth phase of water exists almost everywhere in nature, especially in the human body (high water content). It is driven by solar (or external) energy, which, when absorbed by water molecules, splits them apart. As a consequence, the freed negative moieties align to generate what Dr. Pollack called an exclusion zone (EZ) that is in fact a layer of pure water in which no particles can be dissolved because of the crystalline-like molecular arrangement. Hence, the buildup of EZ water occurs naturally and spontaneously from environmental energy. This layer of pure water adheres to hydrophilic surfaces, repulsing the positive molecules and moieties. Additional energy input creates additional EZ buildup as well as the concentration of the substrate in the water (Kundacina et al, 2016).

Applying the Concept to Scleral Lenses

In applying this to scleral lenses, we have to consider the fluid reservoir as a pool of water. The scale of the EZ corresponds to the thickness of the fluid in the reservoir.

The energy comes from natural light and maybe from blinking or other shear forces applied to the ocular surface. The water molecules split apart into positive and negative moieties. The forth phase of water theory predicts that a thin layer of negatively charged moieties would align (EZ) along the hydrophilic surfaces—in this case, the epithelial cells of the cornea and the back surface of the scleral lens. This forms a negative capsule in the center of the reservoir, where the natural repulsion force (positive against positive) generates a constant flow, most likely contributing to the suction effect (not negative pressure) that we’ve all witnessed over the years. It can also agglomerate with free negatively charged particles in a plus-minus-plus sandwich described as a “like-like-like” agglomeration.

Debris invades the closed environment of the scleral lens reservoir but cannot dissolve into the EZ zone. It remains trapped in the middle of the fluid vortex in the center of the bowl, right in front of the pupil area, with the particles isolated or gathering in a clouding effect. Sound familiar? This is what we see clinically when patients present with fogging issues: debris circulating in the middle of the reservoir, with no adherence to the lens surface or to the cornea.

Other Applications

I hope that this revelation gave you a wow moment, too. The next step is to apply this concept to the epithelial response when orthokeratology lenses are worn. This theory may drive significant changes in the way we understand this clinical concept and, consequently, the way we design these lenses.

But for the moment, it’s enough to realize how little we know about the behavior of water confined in a closed environment. CLS

For references, please visit www.clspectrum.com/references and click on document #290.