Analysis of the electroretinogram in toxoplasma retinochorioiditis

Abstract

The decision to use therapy in toxoplasma retinochorioiditis depends on the location of the active lesion and the presence of vitreous activity. In eyes with dense vitreous clouding it can be difficult to see whether the macular region is involved or not. In theory the localisation of a lesion can be estimated on the basis of the flash ERG. The standard flash electroretinogram was recorded in 23 patients with inactive toxoplasma retinochorioiditis lesions in the retina. In 17 cases a lesion was present within the central 12 degrees of the visual field, 8 of these had a reduced photopic ERG. In 15 patients lesions were found outside the central 12 degrees, in 8 of whom the scotopic ERG was reduced. We conclude that the ERG can be of use in indicating the scar location in patients with dense vitreous clouding.

Ophthalmic and cone derived electrodiagnostic findings in outbred Miniature Long‐haired Dachshunds homozygous for a RPGRIP1 mutation

“…Noise and variation in retinal light adaptation and background illumination are likely to contribute to the different results between single flashes and flicker recordings. Chorioretinitis scars, as seen in three affected dogs with ERG recordings, reduce photopic ERG recordings in people if the lesion was present within the central 12 degrees of the visual field 14 . However, the chorioretinitis scars in the dogs examined were not affecting the area centralis, the area of maximal density of cones, 15 but were found in the peripheral fundus.…”

Electrophysiological examination in uveitis: a review of the literature

“…ERG is a useful tool in order to locate the lesions (either active or inactive) in eyes with dense vitreous clouding. Riemslag et al89 proved this hypothesis by performing standard flash ERG in patients with inactive Toxoplasma retinochoroiditis lesions, and photopic ERG or scotopic ERG were found to decrease with regard to location (macular region or extramacular region involved, respectively). In active Toxoplasma retinochoroiditis in experimental animals, ERG is abnormal and there is a close relationship between the degree of inflammation and the depression of ERGs 90.…”

“…In active Toxoplasma retinochoroiditis in experimental animals, ERG is abnormal and there is a close relationship between the degree of inflammation and the depression of ERGs 90. In addition, Riemslag et al89 observed some cases with remarkable visual field defects more severe than those expected with regard to lesion size and location; VEP abnormalities (P100 latency delayed) reflected optic nerve affection.…”

The SAG1Toxoplasma gondiiSurface Protein Is Not Required for Acute Ocular Toxoplasmosis in Mice

“…Electroretinography (ERG) measures retinal responses to light and was previously used to assess retinal function in Toxoplasma-infected humans and mice (24,30). To perform ERGs, mice were dark adapted for 18 h and then anesthetized and both pupils were dilated.…”