Morphologic findings in the rabbit retina following irradiation with the free-running neodymium-YAG laser. Disruption of Bruch's membrane and its effect on the scarring process in the retina and choroid
E. van der Zypen, F. Fankhauser, K. Raess and C. England
The scarring process induced within the retina and choroid of pigmented
rabbits' eyes following irradiation with the neodymium-YAG laser (working
in the free-running mode) was examined at the ultrastructural level.
Scarring of the sensory retina proceeded rapidly and was well advanced two
weeks after irradiation, whereas in the choroid, signs of repair were
apparent only after six weeks. This difference in the rate of repair
between the two tissues has a bearing on the scarring pattern in the
retinochoroid as a whole. The severity of damage to the elastic component
of Bruch's membrane also has important consequences in relation to the
repair processes in the retina and choroid. Microfractures within this
layer, while enabling migrating cells of various kinds to penetrate into
the inner collagenous zone, did not prevent complete regeneration of the
retinal pigment epithelium (RPE). In instances of greater rupture, however,
RPE regeneration was found to stop at the border of the break, and the
discontinuity produced within Bruch's membrane and the RPE allowed the
glial scar to expand into the choroid. In this region, new formation of
vessels was not found.
