@ophthalmocoach: Dry Eye Explained: TBUT Test 👁️💧 The Tear Break-Up Time (TBUT) test is one of the simplest and most informative tools for assessing tear film stability in patients with dry eye disease. 🔹 What does TBUT measure? It evaluates how long the tear film remains stable on the ocular surface after a blink. 🔹 How is it performed? After instilling fluorescein dye, the patient blinks once and then keeps their eyes open. The time from the last blink to the first appearance of a dark spot (tear film break) is measured under cobalt blue light. 🔹 Normal values: • ≥ 10 seconds — normal tear film stability • < 10 seconds — tear film instability • < 5 seconds — severe dry eye 🔹 Why is TBUT important? A reduced TBUT is a key sign of evaporative dry eye, often associated with meibomian gland dysfunction, increased tear evaporation, or poor lipid layer quality. 🔹 Clinical value: TBUT is fast, non-invasive, and essential for: ✔ Dry eye diagnosis ✔ Treatment monitoring ✔ Contact lens intolerance assessment ✔ Pre-refractive and cataract surgery screening ⚠️ Important note: TBUT can be influenced by fluorescein volume and examiner technique — consistency matters. Understanding tear film stability is the first step toward effective dry eye management #eye #ophthalmologist #optometrist #medicine #doctor
