Visual Loss Following Removal of Intraocular Silicone Oil.

Abstract

Abstract: : Purpose:To report and investigate the cause of visual loss following removal of intraocular silicone oil for retinal detachment. Methods:Analyses of the outcome of two cases following removal of intraocular silicone oil. Both patients previously underwent pars plana vitrectomies and silicone oil injection for macula on rhegmatogenous retinal detachments. Snellen visual acuities were recorded before and after surgery. Visual field tests, fundal fluorescein angiograms, optical coherence tomography and Electrodiagnostic evaluations were carried out after surgery. Results:Both patients were high myopes with rhegmatogenous retinal detachments. Visual acuity was 6/9 in both patients following vitrectomy, but was reduced to 5/60 in one and 6/60 in the other following silicone oil removal. Clinical examination did not reveal any explanations. Fundal fluorescein angiograms were normal but visual fields test with red target suggest reduce macula function. Optical coherence tomography revealed an area of intraretinal hyper–reflectivity in the macula region in one case. Normal ERG’s were obtained in both cases but all responses were smaller and later in the affected eye as compared to the unaffected eye. The pattern ERG showed a reduced amplitude of P50 wave in one case. Multifocal ERG’s showed a reduction in macula function when compared to the uninvolved eye. Conclusion:Our results indicate that the reduction in visual acuities in these two cases is as a result of a dysfunction in the outer layer of the retina especially at the macula. We speculate that a sudden change to the aqueous milieu may be excitotoxic to the retina.

Keywords: electrophysiology: clinical • excitatory amino acid receptors • retinal detachment