Clinical profile of silicon oil-induced ocular hypertension: A prospective study

Abstract

Background: Silicone oil (SO) is an important adjunct for internal tamponade, especially in eyes with proliferative vitreoretinopathy, diabetic tractional retinal detachments, and traumatic retinal detachments. SO has been associated with complications, such as cataract, keratopathy, and glaucoma. Secondary glaucoma has been reported to occur at any time in the postoperative period with a wide range of intraocular pressures (IOPs) and vision loss. Aim: The aim of this study is to assess the incidence and clinical profile of SO-induced ocular hypertension (SOIOH) at our institution, after pars plana vitrectomy (PPV) and silicone oil tamponade (SOT) in patient requiring the procedure. Materials and Methods: This is a prospective study of patients who attended Minto Ophthalmic Hospital, Regional Institute of Ophthalmology, Bengaluru from November 2017 to October 2020 who were requiring SOT for various vitreoretinal pathology. Preoperative complete ophthalmic evaluation was done, starting from visual acuity recording using Snellen's chart, slit-lamp examination, IOP measurement using Goldmann's applanation tonometry, gonioscopy, and dilated fundus examination. A standard three-port PPV with SO injection was performed. SOIOH was defined as IOP >21 mmHg after a period of 3 weeks postoperative, which required either medical or surgical therapy. Patients who developed SOIOH were compared to those who did not develop SOIOH (SOIOH free group), in terms of age, length of SOT, presence of retained SO in anterior chamber and angle, and IOP outcomes. Results: Among 26 patients who met our inclusion criteria were evaluated. Among them, 19 (73%) were male and 7 (27%) were female. The mean average age of all the patients was 36.88 (standard deviation [SD] 17.53) ranging from 10 years to 63 years. The mean average IOP of all patients preoperatively was 13.77 mm of hg (SD 3.45 mm of hg). It increased postoperatively showing a mean average postoperative IOP of all patients as 26.08 mm of hg (SD 11.2 mm of hg). The mean overall increase in IOP postoperatively was 12.31 mm of hg (P = 0.001). The mean average preoperative IOP was 12.2 mm of hg and mean postoperative IOP was 15.4 mm of hg in the SOIOH free group, with a mean average IOP spike postoperatively was 3.2 mm of hg (P = 0.061). In the SIOH group, the postoperatively average IOP spike was 15.75 mm Hg with values ranging from 14.75 mm hg preoperative to 30.5 mm hg postoperative (P = 0.001). Interpretation and Conclusions: Patients who underwent PPV with SOT should be followed up for longer period and those who have retained SO in anterior chamber or angles should be followed up more frequently as chances of development of SOIOH is more in them as proved by this study.

Keywords

• intraocular pressure
• silicone oil-induced ocular hypertension
• silicone oil tamponade