104. Jahrestagung der Deutschen Ophthalmologischen Gesellschaft 2006
Abstract
Abstract
FR.02.05 Changes of perfusion and biomechanics of the optic nerve head with age Spörl E., Böhm A. G., Pillunat L. E.
Universitäts-Augenklinik Dresden The knowledge of changes in perfusion and in biomechanics of the optic nerve head (ONH) with age is important for a better understanding of changes in glaucoma. Investigations of ONH blood flow in 103 healthy persons (age between 20-80 years) showed an increase of flow velocity, a reduction of blood volume and of blood flow with age. The resistance increases with age indicating a reduction of the vessel diameter or a lower density of capillaries. The ONH blood flow is autoregulated. With increasing age the perfusion of the ONH is reduced and causes a reduction of the blood supply of the ONH. Also the biomechanics of the ONH changes with age. The rigidity of the whole eye increases with age. Biomechanical investigations show an increase of the stiffness of the LC with age, where crosslinking of collagen by advanced glycation endproducts (AGEs) plays an important role. The tissue stiffening effect of the AGEs in the LC and peripapillary sclera was proved by stress-strain investigation. This biochemical process does not only occur with age but is also accelerated in diabetes. Crosslinking increases the resistance of the collagen against proteolytic enzymes and results in accumulation of collagen in ONH with increasing age. If the LC is stressed by increased IOP or fluctuations of IOP the stress may be reduced by changing the shape. With age this change of shape is reduced due to reduced flexibility of the tissue. The increased stress affects cells of the ONH and causes pathologic reactions. In glaucoma an elevated level of AGEs in the ONH was observed which leads to changed biomechanics. Diabetes is also a risk factor in glaucoma. These results lead to the conclusion that in glaucoma the biomechanical age-dependant changes start earlier and glaucomatous eye ages faster. However, only in combination with an increased IOP the biomechanical changes lead to glaucomatous changes in ONH.
Zurück | Back
|
