1. A method of ocular testing using a testing apparatus having a display and observer controllable means for controlling movement of a cursor on the display, the method comprising the steps of: providing a fixation target on the display at a known target position; detecting when an observer moves the cursor over said fixation target; once the cursor is over the fixation target, providing a new target on the display at a further known target position; detecting if an observer moves the cursor over said new target, the new target then becoming the fixation target; determining that the new target falls outside the observer's visual field if the observer does not move the cursor over the new target; repositioning the new target if it is determined that the new target falls outside the observer's visual field, until it is detected that the observer has been able to move the cursor over the new target, the new target then becoming the fixation target; recording the detected and undetected target positions; and repeating the steps of providing a new target on the display a number of times to build up a visual field of the observer based on the detected and undetected target positions.