Retinal detachment from hyperosmotic intravitreal injection.

Hyperosmotic solutions were injected into the rabbit vitreous to study their effects upon the retina. Injection of 0.05 ml of a 1000 mOsm solution caused rapid whitening of the posterior retina followed by the development of a large detachment and permanent retinal degeneration. The weakest solutions which produced ophthalmoscopically visible changes in the retina (after an injection of 0.05 ml) were near 500 mOsm. Sodium chloride, sodium aspartate, EDTA, mannitol, sucrose, and penicillin were effective at similar osmolarities. An osmotic load in the vitreous caused immediate loss of the c-wave of the electroretinogram (ERG), and a slower decline of the a- and b-waves. The reported intravitreal toxicity of some drugs may relate to osmotic rather than pharmacologic effects. Osmolarity should be accounted for in planning the amount and location of any vitreous injection.