Retinal breaks invariably display an area deficit. The area contained by the outer edge of the break is always greater than the area of the operculum it contains, implying contraction of the operculum, or expansion of the outer edges of the break, or both. These processes (contraction of the operculum and enlargement of the outer perimeter of the break) are evidence of in-plane stress that results from in-plane strain, and their consequence is the structural failure that is a retinal break. The area deficit can be resolved into circumferential and antero-posterior elements, either of which may dominate, or be absent, in any particular break. The relative bias toward anteroposterior or circumferential shortening suggests the principal meridian of stress in the retina before the break occurred. In this paper a collection of breaks video-recorded during surgery to repair rhegmatogenous retinal detachment is presented, together with analysis of the area deficit contained within the the envelope of the break. The analysis of alignment of the area deficit suggests not only the dynamic stress that caused the break, but also the optimal alignment of a scleral buckle employed to close the break.
