Morphologic, Biomechanical, and Compositional Features of the Internal Limiting Membrane in Pathologic Myopic Foveoschisis.

Purpose: To investigate alterations in the morphologic, compositional, and biomechanical properties of the internal limiting membrane (ILM) in pathologic myopic foveoschisis (MF) eyes.

Methods: ILM specimens were peeled from 61 eyes with MF and 56 eyes with stage III/IV idiopathic macular hole (IMH) as a control. Samples were analyzed for transmission electron microscopy (TEM), scanning electron microscopy, immunofluorescence, Western blotting, and atomic force microscopy. ILM characteristics were compared between the two groups.

Results: TEM findings revealed that thickness of the MF ILMs significantly decreased compared with that of IMH ILMs (0.753 ± 0.215 vs. 1.894 ± 0.247 μm; P < 0.0001). The vitreal side stiffness of the MF ILMs was markedly higher than that of the IMH ILMs (3.520 ± 0.803 vs. 0.879 ± 0.230 MPa, P < 0.0001). Comparing with the IMH group, collagen IV exhibited decreased concentration and different immunofluorescence distribution in ILMs of MF eyes, so also protein α3 (IV), α4 (IV), and α5 (IV). The immunofluorescence staining results showed that astrocytes were observed in none of the IMH eyes and in 12 of 16 MF eyes (75%, P < 0.0001).

Conclusions: These alterations in the MF ILMs appear to be associated with Müller cell and astrocyte reactive gliosis. The present findings contribute to a more in-depth understanding of the pathogenesis of MF.