Abstract
Purpose: :
To evaluate the physiologic and pathological microarchitecture of the posterior vitreous by spectral domain-optical coherence tomography.
Methods: :
934 eyes of patients with various retinal diseases were examined by simultaneous confocal scanning laser ophthalmoscopy (cSLO) and spectral domain-optical coherence tomography (SD-OCT, 870 nm, 40.000 A-scans/sec) in a combined instrument (Spectralis HRA+OCT, Heidelberg Engineering, Heidelberg, Germany). SD-OCT images were evaluated retrospectively with respect to morphological changes in the posterior vitreous and in pre-retinal structures. Brightness levels of the captured SD-OCT images were adjusted. Delineation of the posterior vitreous was possible in an area of 30°x 30° with a depth up to 1.5mm.
Results: :
A vertical and horizontal SD-OCT scan through the foveal centre was available in all eyes studied. In 851 eyes the posterior vitreous could be distinguished. The majority of patients (73%) without posterior vitreous detachment showed a bowl-shaped, clearly delineated, hyporeflective area in the premacular region which could correspond to the bursa premacularis described by Worst (J.G.F. Worst, Documenta Ophthalmologica Proceeding Series, pp.275-279, 1976). The extent of this structure showed a high variability and could not always be registered in the anterior and lateral direction. It could not be visualized in the cSLO image. In most patients with - at least partial - posterior vitreous detachment or vitreoretinal traction, the posterior hyaloid membrane could be delineated as a hyperreflective band anterior to the retinal layers.
Conclusions: :
Combined cSLO and SD-OCT imaging provides unprecedented in vivo details of the morphology of the vitreous. SD-OCT imaging not only enables for in-vivo-visualization of the vitreoretinal interface and the posterior hyaloid membrane, but also allows for in-vivo-visualization of structural changes of the posterior vitreous for the first time. It might prove a useful tool to further elucidate the pathophysiology and natural history of vitreoretinal diseases.
Keywords: imaging/image analysis: clinical • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • vitreous