Beyond-the-edge proliferation after relaxing retinectomy.

Purpose: To report beyond-the-edge proliferation (BTEP) after relaxing retinectomies (RR) i.e. fibrous sheets stretched between the RR edge and the far periphery; to evaluate the tractional potential and report the long-term course of BTEP.

Methods: Retrospective review of the medical records of 83 patients having undergone a RR between January 2009 and December 2014 to identify patients with BTEP.

Results: Six patients aged 31 to 76 were identified. Retinectomy had been performed for traumatic retinal incarceration in one case and anterior PVR in 5 cases. BTEP occurred within weeks of the RR (earliest: 5 weeks). It was discovered intraoperatively in two patients with silicone oil tamponade, at 7 weeks and 6 months respectively after RR. It recurred over a few months after excision in 5 patients, causing inferior tractional retinoschisis in 4 patients and inferior tractional retinal detachment in two patients.

Conclusions: BTEP is an unusual form of proliferative vitreoretinopathy developing despite the absence of the usual vitreo-retinal support (excised during RR), probably through compartmentalization and cell migration along the inferior interface between silicone oil or gas and the aqueous humour. BTEP can cause serious retinal traction, develops over weeks after the RR and recurs frequently a few months after excision.