Today there is an increasing need for assistive technology to help people with disabilities to attain some level of autonomy in terms of communication and movement. People with disabilities, especially total paralysis is often unable to use the biological communication channels such as voice and gestures hence digital communication channels are required. Research on Human Computer Interaction (HCI) is striving to help such individuals to convert human intentions into control signals to operate devices. The technique of measuring cornea retinal potential associated with eye movement is called Electrooculography. Eye movements are behaviors that can be measured and their measurements provide the sensitive means of learning about cognitive and visual stimuli. A human eye conveys a great deal of information with regards to the direction of the eye movements. Further, the direction in which an individual is looking shows where his or her attention is focused. Eye movements are naturally divided into three categories one is the saccades in which eyes quickly change the point of fixation and another is a smooth pursuit movement in which eyes to closely follow a moving object at a steady coordinated velocity, rather than in saccades and the other is a vergence movement in which eye rotates in the opposite direction. By tracking the position of the eye movement useful interfaces can be developed that permit the user to commune and control in a more general way. This paper convey some basic idea about various feature extraction techniques and classification techniques used to categorize the eye movement tasks and also it gives a vision on different issues associated in the field of Electrooculography based Human Computer Interface.