Читать книгу Essentials of Veterinary Ophthalmology - Kirk N. Gelatt - Страница 23

The primary vitreous forms posteriorly, between the primitive lens and the inner layer of the optic cup. In addition to the vessels of the hyaloid system, the primary vitreous also contains mesenchymal cells, collagenous fibrillar material, and macrophages. Primitive hyalocytes produce collagen fibrils that expand the volume of the secondary vitreous.

The tertiary vitreous forms as a thick accumulation of collagen fibers between the lens equator and the optic cup. These fibers are called the marginal bundle of Drualt, or Drualt's bundle. Drualt's bundle has a strong attachment to the inner layer of the optic cup, and it is the precursor to the vitreous base and lens zonules. The early lens zonular fibers appear to be continuous with the inner, limiting membrane of the nonpigmented epithelial layer covering the ciliary muscle. Atrophy of the primary vitreous and hyaloid leaves a clear, narrow central zone, which is called Cloquet's canal.