The lid wiper and dry eyes

[peter56]

The lid wiper contains mucin producing goblet cells, that are lubricating the lid margins during blinks and ocular movements.
The findings of the prof. Knop Team on the mucin-water gel layer at the lid wipers, does have far reaching implications and
consequences for many dry eye patients.
It seems now certain, that the meibum- Lipid layer does only slow down the tear film evaporation, but is not very much related to the gliding
of the ocular tissues.

Considering the fact that the eyes do make more than 3 mil blinks in a year it is most important, that so many blinks do not cause much
mechanical frictions and attritions to the ocular surface epithelium and the lid margins.
The 6 layered tear film does contain mucins and lubricin, that do reduce the mechanical frictions of the eye movements.

At the lid wiper line, there are superficial goblet cell clusters and deeper located goblet cell crypts.
These goblet cells are contributing mucins to form a water-gel cushion at the lid wipers - contact or touching point-line of the eyelids to the ocular surface.

It is most important, that the movements of the lids and the globe is a gliding without any mechanical resistance, like rubbing or pushing of the conjunctiva.
The water-gel cushions at the lid wipers do make it possible, that the lid margins and the ocular surface have no direct contact during the blinks.
It seems, that the water-gel layer at the lid wipers do move on the tear film-Lipid layer. So two mucin-mucous layers are moving on each other.
At the same time, the lid wipers do distribute the tear film during every blink over the ocular surface.

Unfortunately up to now, it is not possible to Diagnose visually the status of the goblet cells at the lid wipers.
In the majority of mild dry eyes, there are still the gel-cushions at the wipers.
But in moderate to severe dry eyes, first the superficial and later on also the deeper goblet cells crypts are being damaged or
destroyed totally. Then every blink will cause pain and frictions.

We do know, that the goblet cells in the conjuctiva do come back, after the inflammation and the dryness have gone.
But currently nobody does know, if the goblet cells at the wipers will return too.

Currently the only Option available is the Labial - lip glands transplantation to the fornix of the upper and lower eyelids.
The labial glands do not produce the same mucins like the lid wiper goblet cells, but very similar ones.

So dry eye patients do face,
aqueous - watery tear deficiency - including bubricin deficit,
meibum-lipid layer deficiency - low quantity and bad quality meibum,
and mucins deficiency at the lid wipers!

In the ophthalmologists community there are almost no responses regarding the lid wiper issues.
Maybe there are some new findings presented at the ARVO meeting.

I hope the drawing does illustrate the structures of the lid wipers.

[surya]

That is what I think so too. Mechanical irritation is the primary reason for blood vessel growth and redness on my conjunctiva. Mucin is the most important of all three layers and I think one wouldn't even notice dry eye symptoms until the mucin layer gets affected. That is when we seek medical help. Morning redness could also be primarily due to mucin deficiency because in that case lids will be in direct contact with the conjunctiva.

[browneyesblu]

First of all Peter56 I want to say that I have been following your posts with great interest, thank you so much for taking the time to research all this. I note you say that there is no way to diagnose the status of the goblet cells at the lid wiper margins. When a drop of lissamine green dye is instilled, I think that makes it possible to see damaged goblet cells on the ocular surface, does it not also stain those at the wipers? Or are those just not visible because of their location?

Does this mean that, when Dr. Korb uses his tiny golf club, he is scraping away damaged goblet cells, or am I confused?

[peter56]

Hi Browneyesblu,
I don`t know, how to visualize the superficial and the one milimeter "deep" goblet cell crypts.
Obviously no ophthalmologist has ever discovered during millions of examinations these goblet cells and the gel cushions at the lid wipers.
I am also very surprised, that no other ophthal or scientist had found these gels-cushions at the lid wiper line.

Until this study of dr Knop the thinking has been, that the tear film and the meibum do contribute the greasy gliding stuff.
The new findings do change the whole diagnostic and therapeutical concepts very much!

So the main reasons for the blinking and movement pain, rubbing and mechanical irritations are the missing or deficient water-gel layer at the lid wipers and not so much the
deficient meibum-lipid layer. one more time, the lipid layer does prevent the fast evaporation.
A rough lid margin without the gel-layer will ruin even the best tear film instantly.
In healthy eyes, two mucin-gel layers are moving on each other.

A good debridement of the lid margins is a very tricky matter and only a very experienced ophthalm-optometrist should perform that.
Even the superficial goblet cell Clusters are very robust.

[browneyesblu]

Thanks Peter. I found an article in which the Knop team published their findings. There may also be a more recent publication with updated findings, this one is from April 2011. It was published in Journal of Anatomy, so I wonder how many opthalmologists even read it. I'm posting the link in case any members want to.

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3077527/