Visualization of the Posterior Vitreous With Dynamic Focusing and Windowed Averaging Swept Source Optical Coherence Tomography

Abstract

To survey the anatomic structures seen in the posterior vitreous using a newly developed technique, dynamic focusing and windowed averaging swept source optical coherence tomography. A cross-sectional study of subjects without a history of eye disease or posterior vitreous detachment. A focused illumination beam was swept through the scan depth during 96 successive B-scans and the corresponding most highly resolved portion of each scan was used to make an averaged composite image. The main outcome measures were the frequency and interconnectedness of anatomic features visualized. There were 44 eyes of 25 subjects, who ranged in age from 23 to 62. An optically empty space was seen above the macula in all eyes, and corresponded to the premacular bursa. Above the optic nerve head was a conical space corresponding to the area of Martegiani. The 2 areas were interconnected in 25 cases (56.8%). Anterior to the premacular bursa was another lacuna, named the supramacular bursa, that was separate from the premacular bursa in horizontal scans centered on the fovea and was found in 38 eyes (86.4%). Both the supramacular and premacular bursae coursed anteriorly and in 21 of the 38 eyes (55.3%) were seen to interconnect. The anatomic arrangement of the vitreous is consistent in living eyes with no posterior vitreous detachment, and does not correspond precisely to that described from dissection studies of autopsy specimens. The constancy of the specific findings suggests there may be some beneficial effect from the architectural structure of the vitreous that enhances evolutionary fitness.