A hypothesis is proposed attributing a number of biotoxic effects to aqueous humor (ABC equals Aqueous Biotoxic Complex). Under normal anatomical and physiological conditions aqueous humour is contained in the anterior and posterior chamber reservoir and the ABC effects remain silent because the boundaries of the aqueous humour reservoir are resistant to these biotoxic factors. These factors are biochemically undefined but fall in the category of collagenolysins and anti-vascular enzymes (Prostaglandins?). Outside the normal reservoir these biotoxic effects result in a specific pathology such as corneal edema, subconjunctival edema, lens fiber edema, macular edema, papilledema and chorioidal edema.