Risk Factors For The Development Of Transient Hypotony After Sinlicone Oil Removal In Aphakia Eyes

Purpose: The study analyzed the risk factors for postoperative transient hypotony after pars plana - clear corneal incision silicone oil removal (PPV) in aphakia eyes to provide a basis for future surgeries and postoperative management of patients.Methods: The records of 76 aphakia eyes of 76 patients who underwent pars plana- clear corneal incision silicone oil removal from March 2007 to December 2010 with at least 4 months of follow-up were divided into 2 groups according to the occurrence of transient hypotony: GroupⅠ: with hypotony occurred (29 eyes) and GroupⅡ: with no hypotony occurred (47 eyes). Risk factors for postoperative transient hypotony after pars plana - clear corneal incision silicone oil removal in aphakia eyes, including age, sex, lateraliy, axial length, the degree of proliferative vitreoretinopathy removal, whether joint intraoperative endolaser applications and scleral cryotherapy ,number of previous pars plana vitrectomies, number of preoperative antiglaucoma ophthalmic solutions, duration of oil tamponade, preoperative intraocular pressure, and duration of postoperative anterior chamber inflammation were observed and analyzed statistically.Results: Transient hypotony occurred in 29 of 76 eyes (38.2%), 27 eyes recovered within 1 week after surgery and the other 2 eyes acquired an IOP of >7 mmHg within 4 weeks after surgery which shows that axial length ( OR=1.586 ) , duration of postoperative anterior chamber inflammation(OR=95.495), number of previous pars plana vitrectomies(OR=1.68) and preoperative intraocular pressure(OR=0.972) are the risk factors, while only axial length( GroupⅠ:25.95±1.56mm,GroupⅡ:22.95±1.10mm) is significantly associated with the development of postoperative transient hypotony (odds ratio =1.586, P = 0.023).Conclusion: The incidence rate of transient hypotony frequently developed after silicone oil removal is 38.2% and most cases recovered within 1 week postoperatively. Axial length, number of previous pars plana vitrectomies, preoperative intraocular pressure, and duration of postoperative anterior chamber inflammation are the risk factors but only axial length has significantly difference. Patients with a long axial length are more likely to develop transient hypotony after silicone oil removal. The reason for the significant difference will be further researched in future studies.