Corpus: Lamina episcleralis
Synonym: episclera
1. Definition
The lamina episcleralis is the outermost layer of the sclera.
2. Histology
The lamina episcleralis contains numerous small blood vessels that send their capillaries into a fine network of collagen fibrils and elastic fibers. Scattered immune cells (lymphocytes, macrophages) are also found in this tissue layer.
The blood vessels of the episclera can be divided into two layers:
- Superficial episcleral plexus: These are radially arranged vessels that become visible in episcleritis.
- Deep episcleral plexus: Deeper vessels that become visible in scleritis.
The episclera is separated from the surrounding Tenon's capsule towards the orbit by the episcleral spatium.