AIM: To evaluate the related risk factors and treatment method of secondary glaucoma after pars plana vitrectomy and silicone oil tamponade.

METHODS: The retrospective study analyzed 114 patients(118 eyes)who were treated with pars plana vitrectomy combined with silicone oil tamponade. Lenses were reserved in 78 eyes and were taken away in 40 eyes among which intraocular lens were implanted in 17 eyes. There were 39 eyes in which the filling time of silicone was no more than 6 months while 79 eyes in which the filling time was more than 6 months. The follow-up time was(16.2±4.9)months. Primary and secondary glaucoma were excluded before the vitrectomy. Silicone oil glaucoma(SOG)was diagnosed when intraocular pressure(IOP)was measured higher than 21mmHg(1mmHg=0.133kPa)three times in succession at least 1 month after silicone oil tamponade and inflammation and neovascular glaucoma should be excluded. Anti-glaucoma drugs were administrated once SOG was diagnosed. If the IOP was not controlled after 2 weeks, the silicone oil was taken away. If the IOP was still high, the anti-glaucoma surgery was operated. The data was analyzed by the SPSS 16.0 software using a binary logistic regression analysis.

RESULTS: Among the 32 eyes of SOG, lenses were removed in 16 eyes(50%). The filling time of silicone oil was more than 6 months in 27 eyes(84.4%)and silicone oil emulsion happened in 20 eyes(62.5%). IOP returned normal in 17 eyes after administrating anti-glaucoma medication within 2 weeks. Silicone oils were taken away in 15 eyes. However, 4 eyes still had high IOP after surgery; one of them was given anti-glaucoma drugs once more; two of them underwent trabeculectomy and one of them underwent cyclophotocoagulation. The lens conditions(whether it was taken away or not, P=0.024), the silicone oil filling time(whether the time was more than 6 months, P=0.014), and the status of the silicone oil(whether emulsification occurred or not, P=0.000)were all found to be significantly related to the incidence of the secondary glaucoma.

CONCLUSION: Removal of lens, more than 6 months of silicone oil filling time and silicone oil emulsion are the risk factors of SOG and anti-glaucoma drugs are the first choice for conservative treatment. If IOP can't be controlled, the silicone oil should be removed in time.