Prefoveal adherent heavy silicone oil following vitrectomy: Incidence, clinical features and risk factors

To study the optical coherence tomography (OCT) and clinical features of all patients presenting with prefoveal 'sticky' heavy silicone oil (HSO) following vitreoretinal surgery and subsequent oil removal.

A retrospective review of all consecutive patients who underwent vitreoretinal surgery with HSO tamponade over 12 years. All OCT scans were reviewed following HSO removal to determine features consistent with residual prefoveal oil deposits. A detailed analysis was performed to investigate potential clinical features and possible associations.Results: Seven cases of prefoveal HSO (pfHSO) were identified from a total of 51 consecutive cases (13.7%). All cases of pfHSO had a tamponade duration exceeding 3 months. The mean tamponade duration in the pfHSO group was 7.8 (3.5-21) months compared to 4.6 (1-9) months in the unaffected group. The use of mixed HSO compared to HSO increases the risk of pfHSO changes (p = 0.024).

In summary, 7 novel cases of sticky prefoveal HSO remnants with variable OCT dimensions were identified which could have an impact on the visual prognosis. Removal of pfHSO is extremely challenging and may not always be possible. There were no pfHSO patients identified below 3 months of tamponade duration.