Scleral Buckling and Ocular Rigidity. Clinical Ramifications

Ocular rigidity is the change in intraocular pressure produced by an incremental change in intraocular volume. Ocular rigidity was determined in 14 donor eyes by injecting small increments of a balanced salt solution through the limbus, while continually monitoring the intraocular pressure with a transducer. A buckling procedure was then performed in these eyes with the use of various solid silicone or stainless steel encircling elements, and the experiments were repeated. Buckled eyes were significantly less rigid than unbuckled eyes, and eyes with higher buckles were significantly less rigid than those with shallower buckles. The observed changes in rigidity are likely secondary to changes in the shape and stress distribution of the scleral shell and are only to a small degree related to the elasticity of the encircling element. Greater volumes of vitreous substitutes, gases, or antibiotics may be injected into buckled eyes compared with unbuckled eyes before excessive intraocular pressures are reached.