Tear Breakup Time

[LauraK]

I just got back from the eye doctor and they ran a Tear Break up Time. My eyes came back at a 5 and 8. Has anyone else had experience with this and been able to see improvements? I am still on Restasis (2 months) and starting Azalite.

[fiddle]

That's not too bad, I've heard of others who have a 1 to 2 second TBT. I'm sure there's still room for improvement though and it's sounds like you're on the right path with good care and lots of help.
fiddle

[fiddle]

P.S. Just another thought on this, while your TBT is better maybe, it is also how well your tears cover your eye. For many of us it is how we feel day in and day out. If your tears aren't properly lubricating your eye then you may not feel much relief from them either.
fiddle

[LauraK]

Thank you for your feedback. My optometrist told me that 5 and 8 were really bad and that it was the worse he has seen post lasik. This wasn't what I wanted to hear. However, I have been reading where 8 is somewhere normal.

[Hopeful2]

Hi Laura,

TBUT measurements vary greatly. I had one doc say my TBUT was 8 sec and within the same week another doc had my TBUT at 3 sec!! It turns out that there is a great deal of variation in how the test is performed, and the resulting TBUT number.

From what I understand, if your TBUT test is done with a drop of the dye from a bottle, then it is possible to get a higher TBUT reading ( over 8 sec ). If however, your TBUT test is done with a drop from a moistened paper strip of dye, then it is likely the TBUT reading will be lower ( 3 sec in my case). Also, TBUT tends to be higher in the morning than in the evening. Rebecca has recently posted an article about this in her blog.

Another TBUT test is the non-invasive TBUT. This test does not use any dye and relies on your sense of dryness for the measurement. What you do is keep your eye open after a normal blink. You count the sec that pass from the blink to the first sensation of burning. The number you get is your non-invasive TBUT. I believe a normal for this test is about 15 sec. Having said that, I did this test on my eye healthy family members and all three came in at a non-invasive TBUT of 8 sec. I like this test because it is non-invasive and I can do it myself! I find that the dye with the numbing chemical really irritates my eyes! They end up being extra sore for a couple of days afterwards.

Hope this helps.

[bakunin]

To what Hopeful2 has said i would like to add that the result of TBUT depends also of the humidity and temperature of the place. If your doctor has an office with strong AC, for sure the TBUT will be lower than if your doctor's office doesn't have AC.

[LauraK]

Thank you for your response. Even so, is 5 and 8 really that bad. He left me feeling like it was very bad.

[robster]

A lot of Optometrists say 10 seconds is average though this isn't strictly true. Over 10 seconds is considered average. 5 seconds is on the low side my right eye is about 5-6 seconds since my LASIK(was 13 before) and I have had horrendous problems with it. My left is 8-9 seconds and I've had very few problems with it. The thing is lots of Optoms will say you shouldn't get problems with anything over 6 seconds but if your TBUT was for instance 13 seconds before LASIK and it's now 8 seconds(just an example) then it is perfectly feasible to have dryness issues as your TBUT will be about 40% lower than before.

Do you know what your TBUT was before surgery? As for your Optom saying that 5 & 8 seconds are the lowest they have ever seen post LASIK I find that very hard to believe. Many people's TBUT in the initial weeks after surgery are lower than your TBUT's my first TBUT(2 weeks after LASIK) were 3 & 4 seconds, though in saying that my eyes felt better than they do now! It is possible to have a low TBUT and have no dryness issues and vice-versa. I wouldn't worry about your TBUT's as they are not super low as like Fiddle said I've heard of people who have had 1 second TBUT.

[littlemermaid]

Also if your eye surface is desensitised due to cornea changes from dryness, damage or chronic use of chemical drops, the blink rate could be deceptive.

LM can easily do a terrifying >1 minute without blinking, and she has been over 2 mins competitively with other children (I do not encourage this ).

Today is a good eye day (no visible signs of inflammation, we have some meibom, some tear film more than normal, but studying all day, using saline drops, so I would expect dry eyes) but she just tested at an astonishing 1 min 7 secs without blinking. Now, during this test, I blinked 4 times, burned and teared up to the point of running. Whereas, she blinked at 1 min 7 secs when she finally felt discomfort but there was no increased tearing even after the blink. And I don't think she was even trying that hard.

Staring at the computer, tv or gaming gets so desiccating and we don't realise that the eye surface is desensitised when it's compromised, so beware everyone - use goggles, humidifier, blink reminder on computer, to heal the eye surface and thus restore the prompts to tears.

I also look at the tear meniscus (pool of tear collecting along the lower eyelid margin, hopefully) and general 'shiny brightness', not scientific, I know. Your optom can measure tear meniscus through the slit-lamp microscope and give you a useful figure.

And I also look at the pupil size by getting a same-age person to stand next to LM in the same conditions. With a compromised cornea, I think the pupil size may be larger compared to 'normal', which makes sense, although I don't know enough about what pupil size means to make this useful.

I think TBUT is basically just someone counting, looking for a useful indicator, not that scientific really because of the variations everyone mentions above. Maybe a staring competition is another useful indicator of how desensitised the eye surface is (sometimes tested with a strand of eg cotton wool from cotton bud gently touching sclera until patient blinks).

So, LauraK, the main thing is that you get lots of medical help and support with your healing process. Have you got wrap-arounds?