Self guaging your TBUT

[jlg_uk]

I once had a TBUT, and was told my eyes were only slightly dry (which they probably were at that specific moment). Personally, I find how long I can go without blinking for without discomfort to be highly variable.

I blink a few times and deliberately avoid blinking until I can start to feel the burning sensation kick in (note not just hold them open for as long as I can stand), counting to myself. My left eye is almost always worse, but the time can vary between over 30 seconds with onion goggles on, down to 1 second when they are bad (or I'm in the cinema).

For me this process seems to be a good way to determine how stable my tear film is. I don't know how close it is to a proper TBUT figure. Maybe everyone does this anyway. But I thought I'd post to offer it up for discussion. Is this a good way to determine how stable your tear film is at that moment in your present environment?

[acarol]

There is a website i came across before where you can test your Tear Break Up - google it and you should find it. Its a timer and you hit return then try keep your eyes open as long as possible then hit return again when you blink. It will tell you whether your Tear Break Up is normal or not.

[jlg_uk]

I wouldn't suggest keeping them open as long as possible - just until you feel the burning sensation start to kick in. For me this threshold is really obvious.

[jlg_uk]

Found some actual info that seems to agree:

http://www.chillibreeze.com/articles...ye-disease.asp

3. Assessment of Tear Film Stability: Non-invasive Tear Break Up Time (NIBUT)
A correlation between ocular discomfort and tear-film breakup time exists.

In hundreds of dry-eye patients, it has been observed that within one second of tear-film breakup time, 73 percent of the patients experience ocular awareness followed by discomfort. This manifestation of ocular discomfort may stimulate the eye to blink, replenishing the tear film and providing protection of the ocular surface. If the patient has a short tear film break-up time due to disease or other factors such as systemic medications known to cause ocular drying or an altered blink rate as a result of staring at a computer screen, symptoms and signs can be exacerbated. Therefore, the relationship between tear-film breakup time and blink rate is critical.

How does one perform the NIBUT?

If you have your patient stare straight ahead and monitor the time from his last complete blink and the moment he reports ocular awareness, this time will be within approximately one second of his tear-film breakup time.

Non-invasive Breakup Test

• Obtain a stop watch or clock

• Blink twice, then stare straight ahead

• Record the time between the last complete blink

• and the first sensation of ocular awareness

This time (in seconds) is the non-invasive breakup time.