The below has the potential to revolutionize the way eye surgeons evaluate the meibomian glands in relation to dry eye complaints.
Right now, we mostly use subjective assessments of the meibomian glands and their overall function. (Unfortunately, there are still eyeMDs, who do not have time to do a thorough examination of the meibomian glands as there are approximately 50 on the top lid of each eyelid and 25 on the bottom eyelid of each eyelid.)
If the group below can create an objective method and machine to quantify the glands and their function, this will help dry eye patients around the world.
J Biomed Opt. 2012 Aug;17(8):086008. doi: 10.1117/1.JBO.17.8.086008.
Detection of meibomian glands and classification of meibography images.
Bioinformatics Institute, 30 Biopolis Street, 07-01, Matrix, Singapore 138671. email@example.com
Computational methods are presented that can automatically detect the length and width of meibomian glands imaged by infrared meibography without requiring any input from the user. The images are then automatically classified. The length of the glands are detected by first normalizing the pixel intensity, extracting stationary points, and then applying morphological operations. Gland widths are detected using scale invariant feature transform and analyzed using Shannon entropy. Features based on the gland lengths and widths are then used to train a linear classifier to accurately differentiate between healthy (specificity 96.1%) and unhealthy (sensitivity 97.9%) meibography images. The user-free computational method is fast, does not suffer from inter-observer variability, and can be useful in clinical studies where large number of images needs to be analyzed efficiently.
The meibomian glands (or tarsal glands) are a special kind ofsebaceous gland at the rim of the eyelids inside the tarsal plate, responsible for the supply of meibum, an oily substance that prevents evaporation of the eye’s tear film. Meibum prevents tear spillage onto the cheek, trapping tears between the oiled edge and the eyeball, and makes the closed lids airtight. There are approximately 50 glands on the upper eyelids and 25 glands on the lower eyelids. The glands are named afterHeinrich Meibom (1638–1700), a German physician.
Lipids are the major components of meibum (also known as “meibomian gland secretions”). The term “meibum” was originally introduced by Nicolaides et al. in 1981. The biochemical composition of meibum is extremely complex and very different from that of sebum. Lipids are universally recognized as major components of human and animal meibum. Recently, an update on the composition of human meibum and on the structures of various positively identified meibomian lipids was published. Currently, the most sensitive and informative approach to lipidomic analysis of meibum is mass spectrometry in combination with liquid chromatography.
In humans, more than 90 different proteins have been identified in meibomian gland secretions.
Dysfunctional meibomian glands often cause dry eyes, one of the more common eye conditions. They may also causeblepharitis, as the dry eyeball rubs off small pieces of skin from the eyelid, which may get infected. Inflammation of the meibomian glands (also known as meibomitis, meibomian gland dysfunction, or posterior blepharitis) causes the glands to be obstructed by thick waxy secretions. Besides leading to dry eyes, the obstructions can be degraded by bacteriallipases, resulting in the formation of free fatty acids, which irritate the eyes and sometimes cause punctate keratopathy.