Slick manoeuvres for silicone oil complications

Although silicone oil has been successfully used by retina surgeons as a tamponading agent for decades, its use can result in a range of complications including keratopathy, glaucoma, hypotony and iritis, among others.

Surgical pearls and various strategies to deal with some of these tricky scenarios were outlined in a EURETINA session devoted to silicone oil complications chaired by Prof José Carlos Pastor MD.

“This symposium will address four of the most frequent complications associated with silicone oil use: increase in IOP, re-proliferations, emulsification and unexplained vision loss,” said Prof José Carlos Pastor MD in his introduction.

He added that two expert groups have been created within EURETINA specifically to address issues relating to emulsification and unexpected visual loss.

“They will issue the results of their work in the near future which we hope will be extremely useful for clinicians,” he said.

Opening the session, the problem of IOP spikes after silicone oil were discussed by Martin Spitzer MD, FEBO.

Dr Spitzer said that while the complication was relatively common, it could be efficiently controlled in up to 80% of cases using topical and systemic anti-glaucomatous medication.

“I would advise using topical aqueous suppressants as first-line treatment given that prostaglandin analogs might promote intraocular inflammation and cystoid macular oedema. Topical cycloplegics and corticosteroids are also recommended to decrease local inflammation in selected cases,” he said.

Jonathan Smith MD then discussed the issue of unexplained visual loss after intraocular tamponades drawing on study data from the British Ophthalmological Surveillance Unit (BOSU).

Owing to the COVID-19 pandemic, only 12 month data could be collected, said Dr Smith. In that period. 26 cases of unexplained visual loss associated with silicone oil were reported, 14 of which were confirmed cases.

The data overall suggests an incidence of 2.7% within the UK, with macular on status considered a key risk factor. Other possible risk factors include duration of oil tamponade and sex, with males having a possibly higher risk.

“Future research needs to be directed towards looking at the most likely low molecular weight components of silicone oil that could cause retinal toxicity,” he said.

Salvador Pastor-Idoate MD, PhD, focused on the role of silicone oil in epiretinal membrane (ERM) diagnosis, management and prevention.

He noted that ERM has a prevalence of around 12.3% in eyes treated with silicone oil and that re-proliferation is the main cause of re-detachment and is strongly related to previous PVR and retinectomies.

“The complications usually appear between 5 weeks and 4 months after surgery. The main risk factors are multiple surgeries, previous PVR, bleeding and above all retinectomies. Unfortunately, there are no pharmacologic treatments for the moment,” he said.

Rosa M. Coco Martin MD, PhD, discussed silicone oil emulsification, how to establish the diagnosis and related clinical factors.

Clinical factors related to issues of emulsification include inflammatory, exudative and vascular diseases, associated techniques and/or medical devices, incomplete filling, eye movements, axial length and younger age.

She explained that the diagnosis can be established using a variety of tools, including fundus examination and ultrawide field imaging, OCT, slim lamp examination, gonioscopy and surgical microscope, anterior segment OCT, ultrasound biomicroscopy and B-scan ultrasound.

Kai Januschowski MD delved deeper into chemical factors related to emulsification and Mario R. Romano MD, PhD, rounded off the session with a talk on the value of viscosity and chemical purity to prevent further complications.

All registered attendees will be able to view this session via playback on the virtual platform.