Peripheral Degenerative Retinoschisis: Imaging Evidence for Two Distinct Structural Configurations

PURPOSE: To characterize vitreoretinal architecture in peripheral degenerative retinoschisis using high-resolution swept-source optical coherence tomography and to distinguish two morphologically and potentially mechanistically distinct forms of retinoschisis. METHODS: This retrospective imaging study evaluated eyes with peripheral degenerative retinoschisis using swept-source optical coherence tomography with extended dynamic-range processing and volume rendering. Retinoschisis was categorized as columnar retinoschisis, with residual intraretinal tissue columns, or bullous retinoschisis, with a large intraretinal cavity. Anatomical features were assessed descriptively and interpreted in the context of retinal physiology. RESULTS: Nineteen eyes of eleven patients were analyzed. All eyes demonstrated regions of columnar retinoschisis, and thirteen eyes also showed bullous retinoschisis. Vitreoschisis was identified only in eyes with bullous retinoschisis. Imaging commonly showed adherent cortical vitreous overlying schitic regions, with adjacent vitreous liquefaction, a configuration inconsistent with sustained traction as the sole explanation for the schisis cavity. Columnar retinoschisis was associated with limited separation between retinal layers and was typically contiguous with bullous schisis, which showed substantially greater intraretinal cavity height. CONCLUSIONS: These findings support the distinction between columnar and bullous retinoschisis as separate morphologic entities. While vitreous traction may contribute to initiation of retinoschisis, progression to bullous schisis may involve additional mechanisms. Loss of Müller cell columns may remove both a structural element that limits expansion of the schisis cavity and a pathway for intraretinal fluid regulation through the deep capillary plexus, allowing metabolic water production to contribute to cavity enlargement in the absence of sustained mechanical forces.