http://http://www.dry-eye-institute.org/lectures.htm
THE IATROGENIC DRY EYE AND ITS MANAGEMENT
Frank J. Holly, Ph.D.,
Based on the Harold Stein Lecture given at the CLES Meeting, in Orlando, FL on 01/23/03. Revised on 03/31/03
Slide 23: What about Lipid Oil ?
THE IATROGENIC DRY EYE AND ITS MANAGEMENT
Frank J. Holly, Ph.D.,
Based on the Harold Stein Lecture given at the CLES Meeting, in Orlando, FL on 01/23/03. Revised on 03/31/03
Slide 23: What about Lipid Oil ?
In addition to the punctal plugs the use of ointments in the eye also belongs to this category. We have already mentioned their use to prevent nocturnal lid adherence due to lack of lubrication. Due to the importance, we repeat our warning here. Ointments consist of apolar lipids which are intensely hydrophobic. Smearing ointment over the ocular surface could not possibly improve tear film instability and the mucin layer cannot possibly mask such a large amount of lipid. Blurry vision often results. The only reason, the use of ointment at night does not result in a complete fiasco is its complete lack of polarity. It cannot spread over hydrophilic surfaces and therefore it is not a tenacious contaminant. Still, it is wise not to rely on ointments in managing dry eye symptoms as it presents another obstacle to the tear film system attempting to form a continuous tear film over the ocular surface.
While various oils often serve as lubricants in machinery, in the human body, almost exclusively aqueous macromolecular solutions serve such a purpose, such as synovial fluids in joints. The lubricant for the relative movement of the lid and the globe is also an aqueous (tear) layer. Attempting to prevent contact adhesion with heavy doses of mineral oil and other nonpolar lipids) ointments interfere with lubrication as well as with visual acuity.
While various oils often serve as lubricants in machinery, in the human body, almost exclusively aqueous macromolecular solutions serve such a purpose, such as synovial fluids in joints. The lubricant for the relative movement of the lid and the globe is also an aqueous (tear) layer. Attempting to prevent contact adhesion with heavy doses of mineral oil and other nonpolar lipids) ointments interfere with lubrication as well as with visual acuity.
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