The correlation of pars plana incision and transient hypotony after silicone oil removal

BACKGROUND AND OBJECTIVE: To evaluate the correlation between pars plana incision and transient hypotony after silicone oil removal in aphakic eyes PATIENTS AND METHODS: Twenty-two patients with apha-kia and a high degree of myopia with silicone oil tamponade were recruited for this prospective study and randomly scheduled to two groups for silicone oil removal: 3.5-mm corneal incision with suture corneal or 20-gauge pars plana incision with suture. Intraocular pressure (IOP) was measured and fundus and anterior structure were examined preoperatively on the first, third, and seventh postoperative day and at 1 month after surgery. RESULTS: IOPs in the pars plana group were significantly lower than the corneal group on the first and third day after surgery (P < .001). Nine of the 11 patients in the pars plana group suffered ciliary detachment accompanied by hypotony (IOP < 8 mm Hg), among whom three patients exhibited excessive hypotony (IOP < 5 mm Hg), whereas the ciliary bodies remained tightly attached and IOP was normal in the corneal group. Among these nine patients, six eyes were observed to have multiple silicone oil granules in the supraciliary cavity, three exhibited gaps of pars plana below the scleral incision site, and two had vitreous hemorrhage. Hypotony spontaneously relieved at the seventh postoperative day for all patients. CONCLUSION: Pars plana incision is the crucial cause of ciliary detachment and consequent transient hypotony after silicone oil removal. Using corneal limbus incision in patients with aphakic eyes to avoid the par plana incision is expected to reduce the incidence of hypotony with minimal complications.