Both lipids and mucins contribute to the stability of the tear film and lipids may inhibit tears from evaporating. Younger people have lower lipid viscosity, higher lipid volume, and a lower rate of tear evaporation. Since age-related changes in human meibum composition and conformation have never been investigated, as a basis for the study of lipid-associated changes with meibomian gland dysfunction, we used the power of infrared spectroscopy to characterize hydrocarbon chain conformation and packing in meibum from humans without dry eye symptoms in relation to age and sex. Meibum from normal human donors ranging in age from 3 to 88 years was studied. Meibum phase transitions were quantified by fitting them to a 4-parameter 2-state sigmoidal equation. Human meibum order and phase transition temperatures decrease with age and this trend may be attributed to lipid compositional changes. If meibum has the same thermodynamic properties on the surface of the tears as it does on the lid margin, a decrease in lipid-lipid interaction strength with increasing age could decrease the stability of tears since lipid-lipid interactions on the tear surface must be broken for the tear film to break up. This study also serves as a foundation to examine meibum conformational differences in meibum from people with meibomian gland dysfunction.
Introduction: Board Certified Ophthalmologists are frequently involved in overseas volunteer eye surgery trips to the developing nations. While the bulk of these missions involve the restoration of vision through sight-restoring modern cataract surgery, subspecialists, such as pediatric ophthalmologists, are taking an increasing role in these clinics. This presentation will discuss the various roles that the pediatric ophthalmologist may take. Methods: The role of the pediatric ophthalmologist in several different volunteer settings will be examined. These include work clinics in Vietnam, teaching clinics in Zimbabwe, and disaster relief sessions in Banda Aceh, Indonesia. Results: Depending on the setting, the pediatric ophthalmologist can assume several disparate roles. Discussion: To adequately contribute on a volunteer mission, the pediatric ophthalmologist must be flexible and prepared to assume different responsibilities, from didactic teaching to surgical instruction, from demonstrative surgery to high-volume surgery, and in the case of disaster relief, to nonpediatric eye surgery. Conclusions: Teaching clinics, work clinics, and disaster relief all present varied challenges to the volunteer pediatric ophthalmologist. To be a contributing member of a volunteer mission, many skills are necessary.
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