Abstract
Purpose: :
To examine ultrastructural correlates of spectral domain OCT (SD-OCT) findings in patients with vitreomacular traction (VMT) syndrome.
Methods: :
Six eyes of six consecutive patients who underwent pars plana vitrectomy with membrane peeling for VMT were included in this study. Each eye underwent complete ophthalmic examination pre-operatively including SD-OCT (Topcon, Paramus, NJ), which captures 128 b-scans over a 6 x 6 mm area in 3.6 seconds, from which 3-dimensional reconstructions were created. Intraoperatively, the vitreous cone surrounding the area of macular traction was released from the remainder of the posterior hyaloid face. After peeling this portion of the posterior hyaloid from its attachment to the central macula, the specimen was collected, fixed in glutaraldehyde, and examined with electron microscopy (EM). In one case, an epiretinal membrane (ERM) adjacent to the area of VMT was peeled from the retina after the vitreous cone was removed, harvested separately, and analyzed by EM.
Results: :
Partial posterior vitreous detachment with focal vitreoretinal adhesions were observed with SD-OCT in all six eyes. In addition, all eyes showed focal areas of hyper-reflectivity by SD-OCT on the retinal surface, suggestive of ERM, which extended past the perifoveal vireoretinal attachment and along the undersurface of the detached posterior hyaloid face. One eye also had a full-thickness macular hole that resulted from the vitreous traction. Ultrastructural analysis showed native collagen (10 nm, 5 of 6 eyes) or new collagen (100 nm, 1 of 6 eyes) with internal limiting membrane (ILM, 4 of 6 eyes). Various cell types not normally found in the vitreous cavity were seen on the vitreous side of the vitreoretinal interface, including RPE cells (6 of 6 eyes), fibroblasts (4 of 6 eyes), and macrophages (3 of 6 eyes). The ERM that was separately analyzed consisted of native collagen (10 nm) sandwiched between ILM and RPE cells, suggesting vitreoschisis.
Conclusions: :
SD-OCT and EM confirmed the presence of firm, fibrocellular vitreoretinal attachment in the setting of partial posterior vitreous detachment and VMT syndrome. The deposition of newly-formed collagen, the presence of non-native cells on the vitreous side of the vitreomacular interface, and the growth of ERM bridging from the retinal surface to the undersurface of the posterior hyaloid face, may help to explain the firm vitreoretinal adhesions associated with VMT.
Keywords: vitreous • retina • macula/fovea