To compare localized retinal function with corresponding histopathologic findings in advanced retinoblastoma.
The medical records and specimens of 7 children with Reese-Ellsworth stage V retinoblastoma (8 eyes) were retrospectively reviewed from January 1, 2005, through March 1, 2008. The patients underwent multifocal electroretinogram (mfERG) testing while imaging of the fundus was being performed. After enucleation of these eyes, retinal layers in a 10-mm-long section centered on the optic nerve were scored for histopathology.
Visual acuity at presentation was 20/3000 to light perception in 6 of 6 eyes. Histopathologic analysis of the central retina revealed atrophy of all retinal layers in 4 eyes, moderate atrophy in 2 eyes, and mild atrophy with intact photoreceptors in 2 eyes. The mfERG amplitude was extinguished, moderately reduced, or mildly reduced when there was severe, moderate, or minimal atrophy of the outer retinal layers, respectively.
In advanced retinoblastoma, the mfERG amplitude provides a functional index of histopathologic retinal damage. When the retina is attached at presentation, the presence of a recordable mfERG indicates the potential for vision. When the retina is detached at presentation and reattaches after chemotherapy, the presence of a recordable mfERG also indicates the potential for limited vision. When the retina is detached or reattached, extinction of the mfERG is associated with severe retinal damage that may preclude visual recovery.