Intraocular Pressure Change and Sustained Intraocular Pressure Elevation After Pars Plana Vitrectomy

OBJECTIVES: The aim of this study was to investigate the incidence and influential factors of changes in intraocular pressure (IOP) and sustained IOP elevation (SIOPE) after an uncomplicated pars plana vitrectomy (PPV). METHODS: In all, 41 eyes of 41 patients who underwent PPV due to the presence of epiretinal membrane, macular hole, or vitreomacular traction syndrome were included in the study. In the vitrectomized eye, an elevated IOP of ≥21 mmHg or an increase of ≥6 mmHg from the preoperative IOP on 2 or more postprocedure visits or the addition of a new IOP-lowering medication during follow-up was defined as sustained IOP elevation. The results of procedures performed with a 20-G instrument and a 23-G instrument were compared. RESULTS: The mean postoperative IOP was significantly higher than the preoperative IOP in vitrectomized eyes (preoperative IOP: 15.2±3.1 mmHg; postoperative 1st month: 17.4±5.8 mmHg, p=0.018; 6th month: 17.3±2.6 mmHg, p=0.02; 12th month: 16.7±2.6 mmHg, p=0.020). While no significant difference in IOP was detected between the vitrectomized and fellow eyes preoperatively, the IOP was significantly higher in the vitrectomized eyes in the 1st, 6th, and 12th months (p=0.040, p <0.001, p <0.001, respectively). SIOPE was detected in 15 vitrectomized eyes (37%) and 1 fellow eye (2%). The postoperative first day IOP was significantly lower in the vitrectomized eyes (11.1±6.1 vs 15.4±2mmHg; p<0.001) and significantly lower in the 23-G group than the 20-G group (9.3±5.2 vs 15.7±5.8; p=0.001). CONCLUSION: IOP may rise significantly in comparison with the fellow eye or the preoperative IOP, even after an uncomplicated PPV. SIOPE and preoperative IOP values should be taken into consideration in addition to cross-sectional IOP findings in the evaluation of PPV.