OPTIC COHERENCE TOMOGRAPHY FEATURES OF SUBRETINAL VITREOUS SUBSTITUTES

Abstract

Purpose : Vitreous substitutes (VS) such as perfluoro-n-octane (PFO), silicone oil (SO) or octafluoropropane (C₃F₈) may uneventfully be retained in the subretinal (SR) space after vitreoretinal surgery. Each VS requires different maneuvers to be removed from the SR space, so it would be interesting to differentiate each VS based on optic coherence tomography (OCT) findings. We compare OCT images of cases of retained SR PFO with cases of retained SR SO or C₃F₈.

Methods : Retrospective analysis of patients with retained VS operated on between 2006 and 2016. All patients were submitted to OCT examination (Heidelberg Tracking Laser System). Demographic data were collected. The following features were analyzed: hyperreflective elevated band at the VS/RPE interface, hyperreflectivity under the bubble; shadow in the choroid at the borders of the bubble; hyperreflective halo around the bubble; bubble shape (totally round vs flat base); hyperreflective apical dot. In cases of multiple bubbles, the presence of septa dividing the bubbles was analyzed.

Results : Data were collected from 9 male and 5 female patients. Median age was 48.7 years old (range 13-76). All patients were submitted to 23-gauge vitrectomy for rhegmatogenous retinal detachment (RD). One patient with SR C₃F₈ had optic disk coloboma. One patient with retained SR SO had recurrent RD.
Elevation of the VS/RPE interface and flat shape of the bubble was noted in all cases; in the12 cases with SR PFO: hyperreflectivity under the bubble noted in 58.3%; shadow 83.3%; Hyperreflective halo 41.6%; hyperreflective apical dot 58.3%. All two cases with multiple bubbles had septa dividing the bubbles. The case with SR SO had no hyperreflectivity under the bubble; no choroidal shadow at the edge of the bubble; + hyperreflective halo; + apical dot; no septum dividing the bubbles. The case with SR C₃F₈ had hyperreflectivity under the bubble; choroidal shadow at the edge of the bubble; + hyperreflective halo; some totally round shape bubble; + apical dot; no septum dividing the bubbles.

Conclusions : Our observations provide hints on the nature of SR VS. Gas may lead to totally round bubbles on OCT; no septa dividing bubbles may rise suspicious on the nature of the SR VS, as both cases that were not PFO presented this sign. Due to its OCT shape, we propose the term “caterpillar” for this sign. Not all SR PFO cases presented with apical dots, as previously suggested in literature.

This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.