a 59-year - old asymptomatic diabetic male was referred to our retinal service with presumed diagnosis of asteroid hyalosis . the patient had undergone laser treatment and intravitreal preserved triamcinolone acetonide injection for clinically significant diabetic macular edema in the right eye 4 years previously . the right eye showed focal laser scars in the macula and several shiny refractile crystalline deposits [ fig . 1 ] . optical coherence tomography localized these deposits to the posterior hyaloid [ fig . 2 ] . these deposits were isofluorescent and not associated with specific angiographic abnormalities [ fig . 3 ] . the patient has been followed for two additional years without any change in the visual acuity or status of the macula . although a posterior vitreous separation has not developed , the crystals have been observed to migrate slowly in distribution . a fundus photograph of the right eye demonstrating small pre - retinal crystals concentrated in the macula , although peripheral crystals are noted ( arrow ) para - foveal optical coherence tomography scan of the right eye demonstrating triamcinolone crystal deposits on the posterior hyaloid surface ( arrow ) fluorescein angiogram of the right eye revealing several micro - aneurysms and focal laser scars , but no crystals , which are isofluorescent triamcinolone has been shown to aggregate into crystalline structures that may resist the washout process and accumulate over the macula . a recent study has identified intra - vitreal triamcinolone acetonide injections , both preserved and preservative - free , as a cause of crystalline retinal deposits . our case report also identifies triamcinolone crystal deposition , all on the posterior hyaloidal surface . with follow - up now extending greater than 6 years , no functional toxic effects have been noted in our patient . whether the crystals retain any biological activity is unclear . in our case and the previous series no adverse visual effect or we suggest the term  drug - induced benign hyaloidopathy and recommend this to be included as a differential diagnosis of crystalline maculopathy and asteroid hyalosis .