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Spontaneous separation of idiopathic epiretinal membrane after retinoid acid use

Dear Editor, Retinoic acid treatment for proliferative vitreoretinopathy to inhibit membrane contraction and proliferation has been mentioned before. However, how retinoic acid works for idiopathic epiretinal membrane has rarely been mentioned in the past. This 44-year-old female patient suffered from progressive blurred vision with mild metamorphopsia over her left eye. She denied any history of systemic disease or trauma. The optical coherence tomography scan revealed epiretinal membrane and macular edema. During follow up from September 2009 to December 2011, the epiretinal membrane and macular edema remained static but vision gradually decreased. After discussion with the patient, she commenced 10 mg retinoic acid oral twice a day from December 2011. During our clinic follow up, adhesion of epiretinal membrane gradually decreased, macular edema decreased and vision gradually recovered. Treatment with retinoic acid ceased in April 2013. The epiretinal membrane underwent spontaneous separation and macular edema subsided. Finally, visual acuity returned to 1.5 with correction (Figure 1). Regarding adverse effects of retinoid acid, there were dry mouth, dryness and peeling of skin, skin itching, muscle pain, headache, and hypercholesterolemia. Our patient only felt mild dry mouth and skin itchy. Those symptoms were tolerable and resolved after finishing the treatment course of retinoid acid. Retinoic acid is a derivative of vitamin A, which can regulate cell growth, differentiation, and extracellular matrix formation in various types of cells. According to a pathobiology study, idiopathic epiretinal membrane contains two major portions, the first is a cellular compartment and the second is an extracellular compartment. Retinoic acid may reduce the secretion of transforming growth factor β (TGF-β) and platelet-derived growth factor (PDGF) to block transdifferentiation of glial cell to myofibroblast, which can control and regulate the contraction of epiretinal membrane. Retinoic acid can also control the extracellular component of the epiretinal membrane. As the cell density increase, the epiretinal membrane contractility may increase. Retinoic acid can not only directly suppress retinal pigment epithelial cell contraction, but also indirectly cause down regulation of laminin concentration to reduce the epiretinal membrane contractility. Retinoic acid can also decrease the epiretinal membrane adhesion and migration with down regulation of the related extracellular matrix. Epiretinal membrane undergoes spontaneous separation and is most commonly seen in younger subjects, females, and myopics. It occurs in approximately 1% of cases overall. Surgical intervention with pars plana vitrectomy combined with membrane peeling is the standard procedure for symptomatic idiopathic epiretinal membrane. Retinoic acid may be effective to modulate the extracellular matrix to increase the spontaneous separation rate of idiopathic epiretinal membrane.