Clinical and spectral-domain optical coherence tomography findings and changes in new-onset macular edema after silicone oil tamponade

Abstract

Backgroud: Few investigations have been conducted on the detailed clinical features of CME associated with SiO, from emergence to restoration, especially using OCT images. This study aimed to analyze the clinical and spectral-domain optical coherence tomography (SD-OCT) characteristics and changes in cystoid macular edema (CME) associated with silicone oil (SiO).

Methods: Retrospective case series. Six cases of newly on-set CME after SiO tamponade were examined. SD-OCT was performed before pars plana vitrectomy, after SiO tamponade, and after SiO removal. Clinical and SD-OCT data was collected.

Results: CME was first noted at 28.83 ± 9.22 days after SiO tamponade. The average foveal thickness was 411 ± 41 μm before oil removal and decreased to 267 ± 69 μm three days after oil removal (P = 0.028). The average visual acuity before and after oil removal were 0.82 ± 0.40 logarithm of the minimum angle of resolution (logMAR) and 0.75 ± 0.45 logMAR, respectively, and the difference was not statistically significant (P = 0.285). SD-OCT revealed that three patients had edema first in the inner nuclear layer (INL), and three had cysts in both INL and outer nuclear layers (ONL) at discovery. Of the six patients, three exhibited cystic changes in the fovea firstly. CME showed rapid recovery following SiO removal, with cysts completely disappearing in four patients (66.7%) within 3 days. However, in two patients (33.3%), the cysts persisted in INL after three days, whereas the cysts in ONL had resolved completely. The ellipsoid zone integrity of the macular region was smoother in patient with better vision.

Conclusion: New-onset CME after SiO tamponade may initially affects INL and then ONL. CME shows significant improvement after oil removal, probably initially resolving in ONL, and then followed by INL. SD-OCT enabless monitoring of macular microstructure changes in SiO-treated eyes, and macular cysts' occurrence can indicate the oil removal need.

Keywords: Cystoid macular edema; Silicone oil eyes; Silicone oil removal; Spectral domain optical coherence tomography.

Fig. 1

OCT images of different periods before and after SiO removal in case 1. A. The OCT 3 days after SiO tamponade did not show CME. B. Cysts appeared in the INL, Henle’s fiber layer and ONL on the 24th day. C. The CME still existed in the INL, Henle’s fiber layer and ONL after 3 months of SiO filling. D. CME completely disappeared 3 days after SiO removal, but the EZ/ELM were disrupted. E. EZ/ELM were gradually recovering 1.5 months after SiO removal (white arrow). F. The continuity of EZ/ELM improved further 6.5 months after SiO removal (white arrow)

Fig. 2

OCT images of different periods before and after SiO removal in case 2. (A) The macular was on without edema before PPV surgery. (B) The OCT 7 days after SiO tamponade showed smooth reflection of macular microstructure. (C) The cysts (white arrow) first formed in INL 42 days after SiO tamponade, and EZ/ELM were continuous. (D) The cysts fused 48 days after SiO tamponade, and no obvious defect was found in EZ/ELM. (E) CME disappeared completely 3 days after SiO removal. (F) EZ/ELM reflection was smooth 6 months after SiO removal

Fig. 3

OCT images of different periods before and after SiO removal in case 3. (A) The OCT 7 days after SiO tamponade did not show CME. (B) Cysts appeared in the INL nasal to the fovea on the 19th day, as shown by white arrow. (C) INL cysts nasal to the fovea became enlarged and obvious 22 days after SiO tamponade. (D) The cysts involved INL around the fovea (white arrow) and extended to the ONL (red arrow). (E) CME spread to Henle’s fiber layer in the fovea (yellow arrow). (F) CME disappeared in ONL 4 days after SiO removal, but not totally in INL (white arrow)

Fig. 4

OCT images of different periods before and after SiO removal in case 4. (A) The OCT 2 days after SiO tamponade did not show CME. (B) The cysts appeared in the INL and Henle’s fiber layer 20 days after SiO tamponade. (C) There was no significant change in CME 4.5 months after SiO tamponade. (D) The CME recovered significantly 3 days after SiO removal, cysts in the Henle’s fiber layer almost completely subsided, but a few remained in the INL (white arrow)