Abstract: A system for measuring the size of a capsular bag of an eye of a subject includes a size indicator and a sizing gauge. The size indicator is configured for insertion into a capsular bag and includes a peripheral portion and a pair of arms. The peripheral portion is configured to engage the capsular bag. Each of the arms has a proximal end and a distal end, the arms being joined to one another at the proximal ends. The peripheral portion is joined to the distal ends of the arms. The arms form an angle that depends on a size of the capsular bag into which the size indicator is placed. The sizing gauge has a body having a front surface, along with first and second features disposed along or behind the front surface. The features are configured to correspond to an angle that is within a predetermined range of angles of the arms of the size indicator when the size indicator is placed within a capsular bag.