Aqueous humor lactic dehydrogenase activity in normal and diseased eyes.

Aqueous humor lactic dehydrogenase (LDH) activity has been determined in 13 normal persons and 116 patients with various ophthalmic diseases. Ten postmortem measurements gave abnormally high values and were not used as a control. Aqueous humor LDH activity in 13 normal eyes ranged from 0 to 22.03 mU/ml, the highest activity being seen in retinoblastoma. This result emphasizes the importance of aqueous humor LDH activity determination in differential diagnosis of retinoblastoma from other ophthalmic disorders.