Purpose: Eye irrigation is a widely accepted therapeutic must in first aid treatment. The burning agent is removed, diluted, and if possible neutralized. Usually water, NaCl 0.9%, Ringer's lactate or phosphate buffer are the most accepted rinsing solutions. We present a relatively new substance called Previn (Diphoterine in countries other than Germany). It is a hypertonic, polyvalent, and amphoteric substance. Its binding energy for acids, bases, reducers, and oxidation is stronger than the binding energy of biological compounds for these burning agents. Concerning its compatibility with the eye and its efficacy, we compare Previn to the rinsing solutions in general use.
Material and methods: The first experiment (I) shows the effects of ocular rinsing with 500 ml Previn in ten healthy human subjects compared with phosphate buffer rinsing. Evaluation is done by slit lamp examination and confocal microscopy. An experimental study (II) compares in vitro buffering capacity (a) of Previn to other rinsing solutions and shows (b) in vivo efficacy of rinsing with Previn versus other rinsing solutions by pH measurements on the corneal surface and anterior chamber of rabbits after a 30-s burn with 1 N sodium hydroxide.
Results: (I) No harmful effect of irrigation with Previn could be found. Its compatibility with the eye is comparable to phosphate buffer rinsing. (II a) Buffering capacity was found to be stronger for Previn in acids and bases compared to phosphate buffer or Ringer's lactate. (II b) The in vivo study on rabbits proved Previn effect onaqueous pH comparable to phosphate buffer in buffering 1 N NaOH, whereas NaCl showed no buffering effect at all.
Conclusion: The above studies have shown that Previn (Diphoterine) is comparable to other rinsing solutions concerning its compatibility with the human eye. Its buffering capacity is comparable to phosphate buffer. Previn and phosphate buffer should only be used in first aid treatment and not for continued rinsing therapy.