Abstract
Purpose: :
To measure retinal function of eyes with retinal reattachment following treatment for retinoblastoma using multi–focal ERG (mfERG).
Methods: :
Multi–focal ERG of three eyes in two patients was performed under general anesthesia. A fundus camera/stimulator projected a 103–hexagon pattern centered on the fovea. Hexagons were flashed according to a pseudorandom binary m–sequence for a duration of 214 flashes. Tumor location was documented with a 60° fundus camera.
Results: :
A 9–month–old with bilateral retinoblastoma (stage V OD, stage IV OS) was initially treated with chemotherapy, external beam irradiation, and multiple applications of laser retinopexy and/or cryoretinopexy. Both eyes showed regression of tumor with retinal reattachment. Visual acuity was 20/400 OD, 20/100 OS. Multi–focal ERG showed global reduction in amplitudes more in the region of regressed tumor compared to the uninvolved peripheral retina. Histopathology revealed tumor regression and atrophy of the overlying retina. Regions of retina without tumor showed cellular loss, reactive gliosis, and vacuolization of the inner and outer retina, findings consistent with chronic retinal detachment. An 11–month–old with bilateral stage V retinoblastoma was treated with three courses of chemoreduction and external beam irradiation. The left eye was enucleated due to tumor progression. In the right eye the retina reattached, the two large tumors regressed but there was subretinal tumor along the inferotemporal arcade. Visual acuity was 20/100. Retinal function in the region of the regressed tumor and macula were severely reduced whereas the nasal retina unaffected by tumor showed higher mfERG amplitudes.
Conclusions: :
The mfERG showed severe reduction in areas of treated tumor indicating irreversible retinal damage in advanced retinoblastoma due to tumor replacement, treatment, and superimposed retinal detachment. The mfERG also demonstrated reduced amplitudes in areas of reattached retina without tumor suggesting that there may be extensive loss of retinal function due to chronic retinal detachment.
Keywords: retinoblastoma • electroretinography: clinical • retinal detachment