Vitrectomy for a secondary epiretinal membrane following treatment of adult-onset Coats' disease.

Purpose: To report a case of adult-onset Coats' disease that had worsening of macular edema and progressive macular traction following cryotherapy and repeated intravitreal bevacizumab injections due to formation of a secondary epiretinal membrane which only improved following pars plana vitrectomy and membrane peeling.

Observations: A 35-year-old male presented with diminution of vision in his left eye and was found to have localized telangiectatic retinal vessels and aneurysmal dilatations with massive exudation and cystoid macular edema. He was diagnosed as adult-onset Coats' disease and treated with cryotherapy and a concomitant intravitreal injection of 2.5 mg bevacizumab followed by 3 monthly intravitreal injections of 2.5 mg bevacizumab and a single injection of 4 mg triamcinolone acetonide. Partial obliteration of the telangiectatic vessels and aneurysmal dilatations with improvement in surrounding lipid and fluid exudate was achieved, however, this was associated with progressive worsening of macular edema and macular traction due to formation of an epiretinal membrane which only improved following vitrectomy and membrane peeling. Effect of therapy at each stage was evaluated using visual acuity testing, fundus examination, fundus fluorescein angiography, and optical coherence tomography.

Conclusion And Importance: A secondary epiretinal membrane can develop following treatment of adult-onset Coats' disease and cause traction especially when combining cryotherapy with bevacizumab injections. Vitrectomy in such cases with membrane peeling may result in improvement of anatomical and functional outcomes.