In 1963 and 1964, three cases were reported of acute uniocular amaurosis concurrent with injections into the scalp of hydrocortisone or methylprednisolone acetate suspensions for regrowth of hair in areas of alopecia areata. Since then, the extreme rarity of visual side effects following local injections of corticosteroids is accounted for by smaller particulate sizes in suspensions (micronized triamcinolone suspensions being used most often for cutaneous injections in the United States) and the injection of diluted corticosteroid suspensions in lesser volume per site. The multiple puncture technique of cutaneous infiltration, whereby pressure of injection and amount introduced per injection can be minimized, further safeguards against embolic consequences.
Selmanowitz VJ, Orentreich N. Cutaneous Corticosteroid Injection and AmaurosisAnalysis for Cause and Prevention. Arch Dermatol. 1974;110(5):729-734. doi:10.1001/archderm.1974.01630110027005