Ocular penetration of hydrocortisone and dexamethasone into the aqueous humour after subconjunctival injection.

The concentration of steroids in the aqueous humour was measured at various intervals after subconjunctival injection in a series of 130 patients of both sexes who came to cataract extraction. Both hydrocortisone acetate (0.5 ml of 2.5 per cent solution) and dexamethasone sodium phosphate (0.5 ml of 0.4 per cent solution) attained a peak concentration in the aqueous of 214.4 and 268.0 micrograms/ml respectively within 10 minutes. Dexamethasone was from 30 to 47 times more effective than hydrocortisone for up to 24 hrs, but the latter provided a reasonably high concentration for up to 7 days.