Risk factors for secondary ocular hypertension in silicone oil-filled eyes following transconjunctival sutureless vitrectomy – A prospective cohort study

PURPOSE: Our aim was to determine the various risk factors for secondary ocular hypertension (OHT) following pars plana vitrectomy (PPV) with silicone oil (SO) injection. METHODS: A prospective cohort study was performed on 46 eyes of 42 patients who underwent PPV with SO injection under a single surgeon between January 2020 and July 2021. Complete ophthalmological examination including gonioscopy and Goldmann applanation tonometry was performed preoperatively and on three postoperative visits, that is, day 7, day 30, and day 90. Axial length and lens thickness were measured at baseline using immersion A-scan. Anterior segment optical coherence tomography (OCT) was used for measuring anterior chamber depth (ACD) at baseline and at 3 months. RESULTS: There was a statistically significant increase in intraocular pressure (IOP) (>21 mmHg) on day 7 (4.70 ± 7.754 mmHg), day 30 (5.24 ± 7.481 mmHg), and day 90 (2.39 ± 5.659 mmHg) (P<0.01 for all). Age <50 years, rhegmatogenous retinal detachment (RRD), and pseudophakia had a strong association with short-term OHT on day 7. Preexisting glaucoma was the only independent risk factor for long-term OHT (day 90). Higher baseline IOP and SO emulsification also contributed to long-term OHT. CONCLUSION: There was a statistically significant elevation in IOP at all postoperative visits. Short-term OHT was associated with younger age (<50 years), RRD, and pseudophakia. Patients with emulsified SO in the anterior chamber, higher baseline IOP, and preexisting glaucoma were at higher risk for long-term OHT.