Fatigue of metals is one of the most common causes of failure. In the first step of the process leading to fatigue damage, strain-localization happens: The cyclic plastic strain deformation is concentrated in the materials as thin bands that are called persistent slip bands (PSB). In  fcc metals, the PSB structure of the walls and channels is observed. With the accumulation of the PSB formation during the cyclic loading, the formed PSB surface grains can protrude on the surface as persistent slip marking (PSM), which consists of extrusions and intrusions that can develop on the surface. Moreover, intrusions can cause fatigue crack initiation due to the slip and un-slip mechanisms at the tips of the intrusions. Therefore, one aspect of inspecting and monitoring the fatigue mechanism is surface roughness development, which can be conducted for fatigue life estimation and prediction. The formation of the PSMs can be represented by the peak height (Rp) and depth of the valley (Rv) on the profile measurement. The modification on the surface can also be present through other parameters such as the gradient value (Rdq, Sdq) and the average roughness (Ra, Sa). Within the investigation uniaxial fatigue tests are carried out using the hypo (42CrMo4 and C45E) and hypereutectoid steels (115CrV3). The surface development is investigated using optical-based measurement methods, which include a confocal microscope and a scattered light sensor. The surface development during cyclic loading can be detected by the used techniques, and the severely developed roughness on the crack origin site at the surface is observed before failure. Moreover, the measured gradient values from both methods are comparable. With various advantages of the scattered light sensor and the results from this study, the scattered light sensor is utilized to study and has the potential to apply real-time monitoring in the real operation to serve the aspect of the fatigue life estimation of actual components.