Abstract
Purpose:
In anomalous posterior vitreous detachment (PVD) there can be a split in the posterior vitreous cortex, known as vitreoschisis. It is that in macular holes (MH), the vitreoschisis split occurs posterior to the level of hyalocytes, while in macular pucker (MP) the split occurs anterior to the hyalocytes leaving them embedded in the outer layer of the posterior vitreous cortex that is still attached to the macula. It is thus hypothesized that there will be greater numbers of hyalocytes in MP membranes than MH membranes excised at surgery.
Methods:
MP (n=5) and MH (n=3) membranes were peeled during vitrectomy employing chromodissection with doubly-diluted indocyanine green dye in MH but not MP. Specimens were immediately fixed in formalin, processed and embedded into paraffin, serially sectioned, and stained with hematoxylin and eosin. Total cell counting in 12 sections per specimen was performed under light microscopy at 100x. The average number of all cells per section was compared in MH vs. MP using an unpaired t-test. High power (1000x) was used for morphological characterization of cells to differentiate hyalocytes/macrophages (circular nucleus) from fibroblasts/fibrocytes and the number of hyalocytes/macrophage cells was compared in MP vs. MH with an unpaired t-test.
Results:
In MP, the mean total cell count was 53.4 cell/specimens vs. 6.0 for MH (P = 0.034). In MP, the mean number of cells with a circular nucleus/specimen was 5, while in MH the mean number of cells with a circular nucleus/specimen was 1 (P = 0.022).
Conclusions:
MP membranes are far more cellular than MH membranes, with a nine-fold greater number of all cells in MP membranes than MH and a five-fold greater number of hyalocytes/macrophages in MP compared to MH. These observations are consistent with the concept that during anomalous PVD in MH the vitreoschisis split occurs posterior to the level of hyalocytes while in MP the split occurs more anteriorly leaving hyalocytes attached to the macula.