Effect of Silicon Oil on Retinal Electrical Functions Using Multifocal Electroretinogram

Retinal detachment is one of the leading causes for permanent vision loss.Incidence of Rheugmatogenous Retinal Detachment (RRD) about 10.5 people per 100,000 population pars plana vitrectomy is the most popular and effective surgical options.

Today, implanting silicone oil as a long-term tamponade is widespread and accepted. However, the oil can emulsify at the interface with its hydrophilic intraocular environment. Eyes treated with silicone oil that emulsifies can show up to 72% long-term complications, including corneal decompensation, band keratopathy, chronic elevations of intraocular pressure, opacification of the crystalline lens, retinopathies, and optic neuropathy.

Silicone oil floats in the vitreous cavity because the specific gravity is 0.97; its bubbles' surface tension may change after injection into the eye. Higher viscosity silicone oils have less emulsification.

In the vitreous cavity, buoyancy and gravity operate on an intraocular tamponade agent that presses against the retina as a downward force. Moreover, interfacial tension is the interaction between two immiscible chemicals, such silicone oil and aqueous humor.silicone oils have viscosities ranging from one thousand (MW 37 kDa) to five thousand (MW 65 kDa).

Multifocal electroretinography (mfERG) is an investigation that can simultaneously measure multiple electroretinographic responses at different retinal locations. mfERG allows topographic mapping of retinal function in the central 40-50° of the retina. The strength of mfERG lies in its ability to provide objective assessment of the central retinal function at different retinal areas within a short duration of time.The mfERG is taken under conditions of light adaptation in order to obtain an electrophysiological response from the cones.

Inclusion criteria

• Patients with primary rhegmatogenous retinal detachment

Exclusion criteria

• Patients with history of previous intraocular surgery.
• Patients with combined traction-rhegmatogenous retinal detachment
• Patients with ocular disease as glaucoma ,degenerative myopia,age related macular degeneration
• Patients with poor fixation.
• Uncooperative patients.
• Patients with retinopathy.
• emulsified SO or complicated SO removal were excluded from this study