CONICET | Buscador de Institutos y Recursos Humanos

Glaucoma is a leading cause of blindness, characterized by specific visual field defects due to the loss of retinal ganglion cells and optic nerve head damage. Recently, we have developed a new experimental model of glaucoma in rats through chronic injections of hyaluronic acid (HA) in the anterior chamber of the eye. HA injections induce an increase of the intraocular pressure (IOP), a progressive retinal dysfunction and a significant loss of ganglion cells and fibers of the optic nerve. The radial optic neurotomy (RON), a surgical strategy originally used for the treatment of the retinal central vein thrombosis, consists in the section in depth of the head of the optic nerve, decompressing the scleral channel and improving the arterial and venous blood flow. The aim of this work was to analyze the therapeutic benefits of RON in the model of experimental glaucoma in rats induced by HA. HA (25 µl, 10 mg/ml) was weekly injected in both eyes of Wistar rat anterior chamber. After 3 weeks of ocular hypertension, the surgical procedure (RON) was performed in one eye from each animal and the contralateral eye was submitted to a sham operation. Retinal function (electroretinogram (ERG) and visual evoked potential (VEP)) was assessed after 10 weeks of ocular hypertension. Moreover, the cell number in the ganglion cells layer (GCL) was quantified. RON significantly reduced the decrease in the scotopic ERG a -wave (sham: 42,20±6,11µV, RON: 50,26±6,03µV, p < 0,05) and b-wave amplitude (sham: 177,75±23,02µV, RON: 195,54±24,67µV p < 0,05), in VEP wave 4 (sham: 50,31±15,08µV, RON: 84,04±15,08µV p < 0,01) and in the number of cells in the GCL (sham: 6,65±0,86 cell/100µm, RON: 11,27±0.35 cell/100µm p < 0,05). These results indicate that RON abrogated histological and functional alterations induced by ocular hypertension, and support the potential use of RON as a new surgical strategy in the treatment of the glaucoma.