The Invasive Tear Break Up Time (TBUT) and Non-invasive Tear Break Up Time (NIBUT) is compared. Invasive TBUT was measured after the instillation of fluorescein on the tarsal conjunctiva and assessed with Slit Lamp Biomicroscopy (SLB), whereas the NIBUT was measured using the Oculus Keratograph 5M (OK5M). The OK5M was invented to overcome the limitation of most other non-invasive method which results in inter-examiner variability. In measuring the NIBUT, the OK5M presents two measurements, NIKf-BUT (the first break up area in second) and NIKav-BUT (the average break up area in second). Hence, the difference between these two measurements was also determined. The result obtained from SLB and OK5M were compared to determine the agreement between these two methods. 50 subjects (30 females, 20 males) were selected among the IIUM Kuantan population. The result showed a significant difference (p