Abstract
Purpose: :
To determine the time required for an apparently optimally secreting meibomian gland (OSMG) to again provide oil for secretion following the drainage of available oil by a constant force.
Methods: :
12 subjects, (10 female, 2 male) were selected for the study. Inclusion criteria included: age 18 - 25 yrs, (mean 21.3 ± 1.9 yrs), no dry eye symptoms, and no history of contact lens wear. Using a standardized technique with a custom made meibomian gland expression device applying a uniform force of 1.28 grams/mm2, an optimally secreting meibomian gland was identified in the central third of each lower lid. The single gland on each lower lid was then marked. A second custom expression device, exerting a force of 1 gram/mm2, facilitating the expression of a single meibomian gland, was used to drain the oil in each marked gland. The time to drain the gland, the time to recover and the time to re-drain the gland were all measured.
Results: :
The mean time taken to drain the meibomian gland was 12.1 ± 3.5 seconds (s), range: 8 - 20 s. The mean recovery time for a drained meibomian gland was 2.17 ± 0.49 hours (h), range = 1.5 - 2.5 h. The mean time to re-drain the meibomian gland after recovery was 5.54 ± 1.9 s, range: 5 - 10 s.
Conclusions: :
This is the first report that a single meibomian gland can be drained of its liquid contents if exposed to a constant force of 1 gram/mm2 for 8 - 20 seconds. The drained gland recovers within approximately 2 hours but provides oil for only half of the original time. This indicates a less than complete recovery.
Keywords: cornea: tears/tear film/dry eye • eyelid • anterior segment