Long-term visual prognosis and characteristics of recurrent retinal detachment after silicone oil removal

Silicone oil (SO) is commonly used for tamponade purposes in retinal detachment (RD) surgery, but the long-term visual prognosis after removal of the oil, and in particular, what is known about the recurrence of RD after SO removal, remains unclear. The purpose of this study is to evaluate the long-term vision prognosis after SO removal, and to understand the frequency and characteristics of RD recurrence.

We retrospectively reviewed the medical charts of 1017 eyes of patients with a diagnosis of RD who had a pars plana vitrectomy with SO tamponade between January 2009 and December 2018. Best-corrected visual acuity (BCVA) was obatained before and after vitrectomy and also at the last visit. After SO removal, the group who showed improvement in visual acuity and the group who did not were compared. The anatomical results were compared between the group in which the retina was detached again after SO removal and the group in which the retina was not detached. To determine whether the duration of SO tamponade affects RD recurrence, further analysis was performed by dividing subgroups according to SO tamponade duration. RD recurrence, visual acuity, SO tamponade period were investigated.

Mean follow-up period was 56.65 ± 72.02 months. An average SO tamponade period was 6.68 ± 11.39 months. The average logMAR BCVA was 1.75 ± 0.91 before SO injection, 1.60 ± 0.75 before SO removal and 1.29 ± 0.96 after the removal. After SO removal, 926 of the 1017 (91.1%) patients had well attached retina without recurrence. There was no significant difference in visual acuity before SO removal in re-detachment group compared to no re-detachment group, but visual acuity of re-detachment group was worse than no re-detachment group after SO removal (p<0.001). The SO tamponade period in the group with improved vision after SO removal was 5.09 ± 9.87 months, and the period was significantly shorter than the 9.09 ± 13.05 months in the group not showing vision recovery (p = 0.005). The occurrence of corneal opacity was significantly higher in the group with SO over 6 months, than those of the two groups with SO tamponade duration of less than 3 months and between 3 and 6 months (p = 0.038). The longest tamponade group showed the worst final vision after SO removal (p<0.001).

The prognosis for final vision is generally good when performing surgery using SO in RD, but considering the complications that arise after surgery, long-term retention of SO is not recommended and the timing of SO removal should be considered.