Postoperative intraocular pressure abnormalities in the Silicone Study. Silicone Study Report 4

Area of Science:

• Ophthalmology
• Vitreoretinal Surgery
• Intraocular Pressure Management

Background:

• Abnormal intraocular pressure (IOP) is a potential complication following surgery for proliferative vitreoretinopathy (PVR).
• The prevalence and clinical significance of chronic IOP abnormalities after PVR surgery using gas or silicone oil tamponade remain unclear.

Purpose of the Study:

• To investigate the prevalence and clinical significance of chronic intraocular pressure (IOP) abnormalities after vitrectomy for severe proliferative vitreoretinopathy (PVR).
• To compare the incidence of IOP abnormalities between perfluoropropane gas (C3F8) and silicone oil tamponades.
• To identify factors associated with chronic hypotony post-PVR surgery.

Main Methods:

• A randomized trial (Silicone Study) involving 241 eyes with severe PVR (>= C-3) undergoing vitrectomy.
• Eyes were randomized to receive either perfluoropropane gas (C3F8) or silicone oil tamponade.
• Chronic IOP abnormalities (hypotony <= 5 mmHg or elevated IOP > 25 mmHg) were assessed over a minimum of 6 months postoperatively.

Main Results:

• Chronic hypotony occurred in 24% of eyes, while chronically elevated IOP occurred in 5% of eyes.
• Elevated IOP was more frequent with silicone oil (8%) than C3F8 gas (2%).
• Hypotony was more frequent with C3F8 gas (31%) than silicone oil (18%), associated with anatomic failure, poor vision, corneal opacity, and retinal detachment.
• Diffuse retinal contraction anterior to the equator was an independent predictor of chronic hypotony (OR=4.2).

Conclusions:

• Intraocular pressure abnormalities are common postoperative complications in eyes with PVR, regardless of tamponade type (C3F8 gas or silicone oil).
• The presence of diffuse retinal contraction anterior to the equator is a significant indicator for surgeons to anticipate postoperative hypotony.