Purpose
To analyze the elastic component of the posterior corneal stromal using electron transmission microscopy and inmunohistochemical techniques.
Methods
Four pieces of cornea and sclero‐corneal angle were included in the study which were obtained from three deceased donors. The mean age was 57,67 years. From each piece a sample of tissue was processed for transmission electron microscopy examination and another sample was paraffin‐embedded for their study using optic microscopy. The optical sections were immunostained with anti‐fibrillin1 antibody.
Results
The ultrastructural study showed that the posterior corneal stroma was comprised of fibrillary collagen lamellae.The number of lamellae vary from 3 to 10 in a random distribution from the line formed by the last queratocytes to the Descemet′s membrane. Mainly, the lamellae were separated by type IV collagen and elastic tissue. There were no differences between fibrillary collagen lamellas of the stroma anterior and posterior to the last line of queratocytes.In all cases, an electrodense band was observed alongside being closely related to the Descemet's membrane. This band was interrupted with gaps between the interruptions that vary in size and shape, like stitching. This band was continued towards the trabecular meshwork, where this material was located principally inside the trabecular sheets. This material appeared to be elastic tissue, this was confirmed by inmunostaining with anti‐ Fibrillin 1 antibody.
Conclusions
Posterior stroma does not constitute a special layer of the cornea. However, a band of elastic tissue is observed close to the Descemet membrane that is continued into the trabecular meshwork. This elastic band could contribute notably to corneal biomechanical properties.