In order to clarify the mechanisms of the ocular hypotensive action of the osmotic agents, rabbits were given glycerol (3cc per kg of body weight, given orally), mannitol (10 cc of 20%, solution per kg of body weight, given intravenously) and acetazolamide (75mg per kg of body weight, given orally).
Before and after administrations of these agents, intraocular pressure, blood osmolality and water contents of vitreous and lens were examined.
All experiments were carried out in paired samples, the right eye as a control and the left eye as, a treated eye.
The fall of intraocular pressure and the rise of blood osmolality following administrations of glycerol and mannitol showed a significant correlation, but not after acetazolamide.
The mean water content of vitreous following administrations of glycerol and mannitol showed a significant decrease. The water content of the vitreous decreased after administrations of glycerol and mannitol, but no change was found after administration of acetazolamide.
The fluorometric studies were performed on the same animals after administrations of glycerol, mannitol and acetazolamide.
The fluorometric values showed a definite rise with glycerol, slight rise with mannitol and profound fall with acetazolamide.
It is clear that the decrease of vitreous volume, due to dehydration, plays an important role in the lowering of the intraocular pressure.
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