Efficacy of intravitreal dexamethasone injection in chronic, atypical, and recurrent central serous chorioretinopathy. A prospective pilot study.

Background: Central serous chorioretinopathy (CSC), characterized by an idiopathic serous neurosensory retinal detachment, has unclear pathogenesis. Choroidal hyperpermeability and retinal pigment epithelial (RPE) dysfunction have been suggested as possible mechanisms. While the benign nature of acute CSC is known, treatment challenges remain for chronic, atypical, and recurrent central serous chorioretinopathy because persistent fluid at macula results in permanent RPE damage and consequent vision loss. Treatment aims to preserve the outer neurosensory retinal layers and achieve complete resolution of the subretinal fluid (SRF) and intraretinal fluid (IRF), as even a tiny amount of remaining SRF can lead to irreversible damage to photoreceptors.

Both thermal and photochemical lasers like photodynamic therapy (PDT) have been advocated for treating these eyes. Chronic CSC (cCSC) with broad and indistinct leakage where thermal lasers are believed to be more damaging, PDT proves to be safer and efficacious in reducing SRF and improving visual acuity. But the non-availability of Verteporfin has forced retina surgeons to damaging thermal lasers in recent times. While both the interventions may result in RPE atrophy, PDT, in addition, may cause choroidal hypoperfusion and neovascular complications. Subthreshold lasers have also been tried in cCSC, but the need for confluent treatment spots in the absence of visible burns is a challenge.

Rationale: Dexamethasone has the highest relative clinical efficacy of any corticosteroid applied to ophthalmology practice and exerts its’ multiple effects via its’ influence on numerous signal transduction pathways. It has been approved for treating macular edema in retinal venous occlusions and non-infectious uveitis. Studies of diabetic macular edema treatment have demonstrated that dexamethasone implant may be an alternative treatment in recalcitrant edema owing to its’ anti-inflammatory, anti-permeability, and angiostatic effects. In age-related macular degeneration, anti-VEFG resistant choroidal neovascular complications responded well to a combination treatment of dexamethasone and anti-VEGF by improving retinal fluid resorption. CSC, a disease in which patients are advised to avoid corticosteroids in all forms anecdotal reports of Intravitreal triamcinolone injection have reported equivocal results. Intravitreal triamcinolone in chronic CSC, in a single case report, Jonas et al. did not find marked benefit, but Patron et al. showed complete resolution of cystoid changes secondary to cCSC.As dexamethasone implant as a rescue treatment in cCSC has never been tried in a prospective clinical study, we intend to determine its’ efficacy in chronic, atypical and recurrent central serous chorioretinopathy.