Light microscopy of uveoscleral drainage routes after gelatine injections into the suprachoroidal space

Abstract

ABSTRACT.Purpose: To visualize the suprachoroidal space and to study the morphology of possible uveoscleral drainage routes in the human eye. Methods: Indian ink stained gelatine was injected directly into the suprachoroidal space of 7 human donor eyes. Those quadrants where gelatine appeared in the episcleral venous network were cut in their entirety in consecutive sections and examined by light microscopy. Results: Gelatine was observed in the connective tissue surrounding scleral vessels and nerves. Gelatine was also traceable in fine, endothelium-lined channels at the inner aspect of the anterior sclera. These channels seemed to originate at the inner surface of the sclera, close behind the scleral spur, and communicate with the intrascleral venous plexus. Conclusion: Fluid is drained from the suprachoroidal space through the perivascular and perineural spaces of scleral blood vessels and nerves. In addition, this study indicates that there are preformed channels at the inner aspect of the anterior sclera, capable of draining fluid directly into scleral veins.

Expression of factor VIII‐related antigen in human aqueous drainage channels

“…The eyes and the histological sections used in this study were identical to those earlier described by Krohn & Bertelsen (1998). Briefly, 7 eyes from 4 human cadavers were injected with Indian ink stained gelatine into the suprachoroidal space.…”

“…These quadrants were cut in their entirety in consecutive meridional sections, stained with hematoxylin-eosin (HE) and examined by light microscopy. Six preformed channels, originating at the inner surface of the anterior sclera, were found (Krohn & Bertelsen 1998). These structures are here referred to as ''scleral channels''.…”

“…However, recent experiments have demonstrated an additional pathway for the fluid transport out of the suprachoroidal space. Both corrosion casting and serial section microscopy have indicated that there are preformed channels at the inner aspect of the anterior sclera, capable of draining fluid from the suprachoroidal space directly into the scleral veins (Krohn & Bertelsen 1997;1998). By light microscopy the scleral channels showed a fine cellular lining, and the main purpose of the present study was to characterize these cells in comparison with the endothelium of Schlemm's canal, the collector channels and the scleral blood vessels.…”

Characterization of Uveoscleral Outflow in Enucleated Porcine Eyes Perfused under Constant Pressure

“…Although, in tracer studies in the rhesus monkey, evidence of outflow through vortex veins has been found, 1-3 no significant amount of tracer was detected in the posterior choroid in human and mouse eyes. 4,5 It is possible that drainage through the choroid occurs in some species but not in others.…”

Transport Barriers in Transscleral Drug Delivery for Retinal Diseases

“…It is then drained either through the trabecular meshwork into Schlemm's canal and aqueous veins (conventional pathway) or directly through the ciliary body and into the suprachoroidal space (unconventional pathway). From the suprachoroidal space, the aqueous humor flows through scleral channels [80][81][82] and is cleared by conjunctival lymphatics ( fig. 3 , uveoscleral flow inset).…”