Letter from Strassburg

1876 Boston Medical and Surgical Journal  
The change in shape of the eye is brought about by a gradual pushing out of its posterior wall. Neither muscular action (on tho part of the ciliary muscle or oblique muscles) brings this about, nor is it caused by forcible expansion of the scierai layers, or of the optic nerve sheath ; it is duo solely to the repeated temporary increase of pressure in the posterior segment of the eye. This repeated temporary increase of pressure in the posterior portion of the eye is chiefly due to congestion
more » ... due to congestion of the uveal tract, und secondarily to exudation of serum in the posterior part of the vitreous. The congestion is caused by the impeded flow of blood from the. vasa* vorticosa.. It is hardly likely that the simple exercise of the accommodation brings this about, but it is almost indubitable that, when the convergence of the visual axes increases, the rectus extornus and tho obliquas inferior muscles severally exert a pressure on the venoi vorticosa; that impedes their circula-
doi:10.1056/nejm187610190951611 fatcat:q35jo5r55nfgrkgjjas5fkaoyy