Implantation of an accommodating intraocular lens in an eye may require the accurate measurement of the size, circumference, or diameter of the capsular bag of the eye. A flexible ring or ring portion may be temporarily or permanently inserted into the capsular bag for measuring the circumference of the capsular bag, for example, after extraction of a natural lens from the capsular bag. The ring or ring portion is generally compressible to fit through a surgical incision, then expands to fill the capsular bag along an equatorial region. The ring or ring portion includes a central component that changes shape and/or angle as the ring or ring portion is compressed. The shape change is generally correlated to the size of the capsular bag and may be visually measured through the cornea, the measurement being generally independent of corneal magnification. The measurement may be used to determine or calculate information about the capsular bag such as its size, elasticity, accommodative range, and so forth.
