This consists in a thinning and protrusion of the cornea in the form of
a blunt cone, without loss of transparency. It has accordingly been
called _staphyloma pellucida_. There is a gradual attenuation and
distension of the corneal tissue from some unknown cause. It has been
seen mainly in the young and is manifestly due to a trophic defect.
Stockfleth records a case in a foal and Bayer in a cow. No satisfactory
treatment has been proposed, but as the trouble usually comes to a
standstill without perforation, it can be left to take its course. With
rapid increase and manifest tension antiseptic puncture of the cornea or
even iridectomy might be tried.