The most common cause of eyelid defect is excision
of lid margin tumour. Trauma is the second most comon cause. Congenital
defect is an uncommon cause.
Reconstruction of the eyelid defect requires three elements:
an outer layer of skin
inner layer of mucosa
semi rigid supporting structure (acting as the tarsal plete)
interposed between them
Compared with the upper lid, the lower lid is not as critical
in maintaining the intergrity of the cornea. Therefore, most of the techniques
used (except Hughes flap) seldom utilize the upper lid component
to reconstruct the lower lid as this may affect the upper lid function.
The following pictures summarize the most useful techniques
for the reconstruction of the lower lid according to the extent of the defect: