Systems and methods are disclosed for obtaining rheological properties of viscoelastic medium, and in particular, in-vivo evaluation of body fluid such as the vitreous. The system includes a needle-like probe having a distal and a proximal end, a rotational actuator, and a sensor coupled to the rotational actuator. The proximal end of the probe is configured for attachment to the rotational actuator. The distal proximal end of the probe has a roughened outer circumferential surface extending axially along at least a portion of the distal end, wherein the roughed distal end of the probe is configured to be disposed within the viscoelastic medium, and wherein the sensor is configured to obtain measurements corresponding rotation of the probe within the viscoelastic medium.