Optic coherence tomography features of subretinal vitreous substitutes

Abstract

Background: To draw comparisons between spectral domain optic coherence tomography (SD-OCT) features of subretinal silicon oil (SO), perfluoro-n-octane (PFO) or C3F8 gas.

Methods: Cases diagnosed with retained subretinal vitreous substitutes (VS) were retrospectively selected. Demographic data were collected and OCT features were analyzed.

Results: In the 13 cases with subretinal PFO, hyper-reflectivity under the bubble was noted in 8 eyes (61.5%); choroidal shadow at the borders of the bubble in 11 eyes (84.6%); hyper-reflective halo around the bubble in 5 eyes (38.4%) and a hyper-reflective apical dot in 8 eyes (61.5%).The two cases with multiple PFO bubbles had complete septum dividing the bubbles. The one case with subretinal SO had hyper reflectivity under the bubble; no choroidal shadow at the edge of the bubble; hyper-reflective halo was noted around the bubble and the apical hyper-reflective dot was present; there was no complete septum dividing multiple bubbles. The single case with subretinal C₃F₈ had some bubbles with totally round base, incomplete septum, hyper reflectivity under the bubble, choroidal shadow at the edge of the bubble, a hyper-reflective halo and an apical dot.

Conclusion: Different subretinal VS share similar SD-OCT characteristics. Round base bubbles are only observed with subretinal C3F8 gas, while incomplete septum are related to retained subretinal SO or gas.

Keywords: Gas tamponade; Ophthalmologic surgical procedures/methods; Perfluorocarbon liquid; Retinal detachment/surgery; Silicone oils/therapeutic use; Vitrectomy.

Fig. 1

SD-OCT demonstrates subretinal silicone oil. There is no complete septum dividing the multiple bubbles—we named this finding as the “caterpillar sign” (star). Note the choroidal shadow at the borders of the bubbles (white arrow)

Fig. 2

SD-OCT demonstrates subretinal C₃F₈ in a case of retinal detachment and optic nerve coloboma. Note hyper-reflective elevated band at the VS/RPE interface and a round base of the bubble above it (arrowhead). Hyper-reflective halo around the retained subretinal gas is also present (arrow)

Fig. 3

Subretinal PFO under the fovea. a Features before surgical removal. Gray asterisk: hyper-reflective apical dot; white asterisk: hyper-reflective halo; white arrow: elevation of PFO/RPE interface. b Post op day 1. The RPE elevation is not noted; image resembles full thickness macular hole, but the roof of the cyst connects the borders. c Seven days post op. Closure of internal retinal layers; absence of subfoveal external layers (white arrow)

Fig. 4

Giant subfoveal PFO bubble. Note the hyper-reflective halo around the flat base bubble, as well as the elevation of the PFO/RPE interface

Fig. 5

SD-OCT demonstrates multiple retained subretinal PFO bubbles. Note the choroidal hyper-reflectivity under the bubble area and hyper-reflective elevated band at the VS/RPE interface under a flat bubble shape (arrowhead). A hyper-reflective apical dot (arrow) and a septum between the bubbles (star) are also present