Evaluation of the glutamate and other aminoacids amounts in vitreous body and corpus geniculatum laterale in patient with glaucoma by mr-spectroscopy

PURPOSE: To evaluate glutamate and other aminoacids levels both vitreous and corpus geniculatum laterale by MR spectroscopy (MRS) in glaucoma patients.MATERIAL AND METHODS: 29 eyes of 29 patients with glaucoma, no existing ocular pathology and systemic disease (group 1) and 13 eyes of 13 healthy individuals whose routine ophthalmologic examinations were normal (group 2) were included in the study. Glutamate-glutamin (Glx)/Creatin/(Cr) ratios and lactate peaks in the vitreous body, and the Glx/Cr, N-acetil aspartate (NAA)/Cr, Cholin (Cho)/Cr ratios, and lactate peaks in the ipsilateral area of corpus geniculatum laterale were evaluated by using MRS in each group.RESULTS: The mean Glx/Cr ratio was 2.24±1.51 in the vitreous body and the mean Glx/Cr, NAA/Cr, and Cho/Cr ratios were 0.38±0.35, 1.44±0.57, 0.79±0.32, respectively in the corpus geniculatum laterale area of healthy individuals. The mean Glx/Cr ratio was 10.87±8.58 in the vitreous body and the mean Glx/Cr, NAA/Cr, and Cho/Cr ratios were 1.29±1.21, 1.15±0.56, 1.36±1.30, respectively in the corpus geniculatum laterale area of glaucoma patients. Moreover, while a lactate peak was established in the vitreous body of 11 glaucoma patients, there was no any lactate peak in the vitreous body of healthy individuals. A statistically significant difference was determined between two groups for Glx/Cr ratio in both vitreous body and corpus geniculatum laterale (p<0.01). There was no statistically significant difference between two groups for NAA/Cr, and Cho/Cr ratios in the corpus geniculatum laterale (p>0.05).CONCLUSION: Determining high amount of glutamate in the both vitreous body and corpus geniculatum laterale of glaucoma patient supports the theory of apoptosis in etiopathogenesis of glaucoma. MRS method, which can measure biochemical structure and metabolites of tissues as well as show on a single spectrum, may be a new and noninvasive method in early diagnosis of glaucoma.