Subclinical visual field alterations are commonly present in patients with Graves' Orbitopathy and are mainly related to the clinical activity of the disease

The present study was aimed to investigate optic nerve involvement by computerized perimetry in 40 (29 women, 11 men) consecutive GO patients not showing definite dysthyroid optic neuropathy (DON). All patients presenting visual acuity defects, pallor or swelling of the optic nerve, concomitant eye disease, evidence of apical crowding or optic nerve stretching at either MRI or CT imaging were excluded. Normal perimetry occurred in 7 patients (17.5%), 5 patients (12.5%) had "indeterminate" results and 28 patients (70%) presented abnormal perimetry. Particularly, 7 isolated paracentral, 5 pericentral and 16 combined peri and paracentral scotomas were found. On the contrary, 15/20 patients in the group without GO had normal perimetry, isolated scotomas were found in 5 cases (1 pericentral and 4 paracentral) and no case of combined scotoma occurred. The difference between the 2 groups was statistically significant (x2 = 9.17; p = 0.025). Overall, the sensitivity resulted 70%, the specificity 75% and the positive predictive value 84.8%. In patients with GO, the proportion of visual field alterations was significantly increased for Clinical Activity Score > or = 3 (p = 0.0005), while no relationship occurred with proptosis degree (p = 0.115). In conclusion, a great proportion of GO patients without clinically evident DON presents visual field defects, mainly related to GO activity.

Curcumin treatment protects rat retinal neurons against excitotoxicity: effect on N-methyl-D: -aspartate-induced intracellular Ca(2+) increase

Curcumin, an extract from the plant Curcuma longa with well-known antioxidant and anti-inflammatory activities, was tested as protective agent against excitotoxicity in rat retinal cultures. A 24 h-treatment with curcumin reduced N-methyl-D: -aspartate (NMDA)-mediated excitotoxic cell damage, estimated as decrease of cell viability and increase in apoptosis. The protection was associated with decrease of NMDA receptor-mediated Ca(2+) rise and reduction in the level of phosphorylated NR1 subunit of the NMDA receptor. These results enlighten a new pharmacological action of the plant extract, possibly mediated by a modulation of NMDA receptor activity.

Perfluorohexyloctane (F6H8) induces structural modifications and increases apoptosis in rat primary retinal cultures

The effects of perfluorohexyloctane (F6H8), recently investigated as a long-term artificial vitreous substitute, were studied in vitro, with the use of rat retinal cultures seeded on microporous inserts that allow the cell layer to be in contact with the material to be tested, on the apical side, and with the nutrient medium, on the basal side. After 72 h of treatment with F6H8, retinal cultures lost the characteristic two-layered organization with glial cells at the bottom and neuronal cells on top of them. They appeared to be composed of only one layer of polyhedrical, flattened, and disconnected cells. TUNEL assay revealed an evident increase in the percentage of apoptotic cells in F6H8-treated cultures (30.1 +/- 4.5), compared to control (10.3 +/- 2.6) and perfluoroctane-treated cultures (10.1 +/- 1.7). Immunolabeling of MAP-2, a protein of neuronal cytoskeleton, evidenced a marked loss of neurites. The results suggest that F6H8 is harmful to retinal cells in vitro and can therefore be potentially noxious to the retina as an artificial vitreous substitute.