What is A TBUT? Tear Break Up Time Test and Why It's a Useful Dry Eye Test That Your Optometrist Can Perform in 10 Seconds ⏱️

 

 

 

Hello there! I'm Dr. Tanya Gill, OD, and today I’m excited to share my most used in-office dry eye test –  the Tear Break Up Time (TBUT) Test. This quick and effective diagnostic tool is pivotal in helping my dry eye patients, and best of all, it only takes 10 seconds to perform! 😊

 

 

Understanding TBUT

• Definition:
  TBUT stands for Tear Break Up Time, which measures the stability of your tear film after a one blink.
• Purpose:
  This test helps me assess how long your tears remain intact on your eye's surface before they begin to evaporate.
• Significance:
  A short TBUT often indicates that your tear film is unstable, which may be a sign of dry eye syndrome.
• Normal Score:
  A TBUT of 10 seconds is a normal, healthy finding. 
• Mild, Moderate or Severe?:
  This scale is according to me, but it offers a good starting point and helps my patients categorize their severity and improvement. Of course there are exceptions per case.
  •  7-10 seconds: mild findings
    
  • 3-6: moderate findings
  • 0-2 seconds: severe findings

 

How is the TBUT Test Performed?

• Step 1:
  Fluorescein dye is instilled in your eye so I can visualize the tear film (with the help of a slit lamp microscope).
• Step 2:
  You are asked to blink a few times to distribute the dye evenly across the surface of your eyes.
• Step 3:
  Under the slit lamp microscope, one last blink before the count begins. I instruct my patient to blink once with BOTH eyes and then try to keep BOTH eyes open for 10 seconds. Here I do 2 things:
  • 1) count to 10 out loud so my patient knows exactly where we are.
  • 2) carefully watch the cornea for dark spots to form, this is where the tears dissipate.
• Step 4:
  Repeat Step 3 on the other eye.
• Step 5:
  I also check the cornea (clear part) and the conjunctiva (white part) for dry spots when the TBUT is completed.

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Why is TBUT So Important?

• Quick & Effective:
  With results in just 10 seconds, it's a rapid and inexpensive way to assess tear stability.
• Non-Invasive:
  The procedure is comfortable, painless, and completely non-invasive.
• Diagnostic Value:
  It helps me determine the severity of dry eye conditions and helps me adjust eye care routines. 
• Early Detection:
  Early diagnosis through TBUT can prevent further complications and maintain optimal eye health.
• Patient Learning:
  My favorite point. Over time and with repetition, my patients can almost predict their TBUT score before we even do the test!

 

Key Takeaway:

The TBUT Test is an essential tool in my diagnostic toolkit. It enables me to quickly and over time, accurately evaluate if dry eye treatment plans are working or need to be modified.