摘要: Publisher Summary The cornea and sclera together form the tough outer tunic of eye, which withstands intra-ocular pressure from within protects contents mechanical injury without. is major component in optical system eye; total dioptric power human eyeball, nearly three-quarters contributed by interface between air. To this end, it curved transparent, its surfaces, particularly external one, are smooth to good standards. Generally, globe mammalian eye approximates a sphere, sometimes rather flattened antero-posterior direction, so that curvature similar. Its radius ranges 1.75 mm mouse 25 horse, among more common animals. In man, lesser extent many other species, than eyeball as whole.