Computer-aided (or computer-assisted) assessment (CAA) includes all forms of assessments students' progress, whether summative (i.e. tests that will contribute to formal qualifications) or formative (i.e. tests that promote learning but are not part of a course's marking), delivered with the help of computers.
There are number of open source online tools to handle exams conducted on OMR sheets.
Technically, assignments that are written on a computer and researched online are computer-aided assessments.
One of the most common forms of computer-aided assessment (in terms of e-learning) is online quizzes or exams.
There are new technologies and tools coming up which can support subjective assessment of evaluation of the user.