The Dry Eye Zone

Rebecca's Blog

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Abstract: Tear glands, tit for tat, and... is this interesting or is this interesting!

Well, kewl - someone's finally speaking my language (so to speak)!

OK so it's only rabbits but I found this extremely suggestive. Has it been all said and done long ago and I just never noticed? Seriously, maybe it's just leaky brain syndrome but I honestly don't remember coming across something like this before, simple as it is.

They cauterized shut the meibomian glands of one eye and observed the effects on the tear film. Aqueous tears (i.e. from the lacrimal glands) increased and goblet cell density (i.e. mucous-makers) DECREASED.

Just playing guessing games here as I'm only looking at an abstract not data but:

Let's agree to ignore the lacrimal gland increase on the basis that screwing with the rest of the tear system has left such a bad surface that the bunnies are getting lots of reflex tearing.

Now look at the goblet cells: We've just simulated severe MGD or MG atrophy, goblet cell density is down so presumably mucous production is down. I've always felt that the 'unexplained' element with some of the patients who have severe burning or other 'surface symptoms' (including the infamous 'menthol sensation), despite decent aqueous production and a relatively quiet LOOKING ocular surface, might have as a common factor poor mucus resulting in poor 'wetting' (in a feeble attempt to speak Dr. Holly's language). If so, this might explain why some of these patients can max out on antibiotics, heat treatment, bleph treatment etc and still be in symptomatic hell. Furthermore, it might also help explain why simply applying something that 'wets' better (like Dwelle) can seriously improve symptoms even if the MGs remain completely unproductive, something I was puzzling over in an earlier post using our DEZ member 'Rozjen''s remarkable experience as an example... So now what I really want to know is whether it just compensates for the absence of the substance that is normally responsible for tear adherence or, as suggested in earlier studies, also actually improves goblet cell density. In due course hopefully we'll actually nail this down. Oh for research dollars. It wouldn't really take all THAT much.

[Changes in lacrimal secretion in rabbits according to meibomian glands activity][Article in Romanian]
Oftalmologia. 2007;51(4):121-5.
Stan C, Visan O, Samoila O, Mogosan C, Craciun C, Mera M.

PURPOSE: The purpose of this issue is to create an experimental animal model of dry eye and study the alteration of lachrymal secretion in time.
MATERIALS AND METHODS: We used a group of 8 rabbits in which the Meibomian gland orifices of the right eye were individually closed by cauterization, the results being related to the sound left eye.
RESULTS: We studied: the quantitative alteration of the lachrymal secretion using Schirmer 1 test; the alteration of lachrymal film using rose-bengal and fluorescein staining; the variation in tear protein concentration and histopathological changes in conjunctiva.
CONCLUSIONS: We found histopatological changes in conjunctiva and in the lachrymal secretion consisting in conjunctival goblet-ceil density decrease and watery secretion increase, probably due to lachrymal viscousity decrease mechanism.
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