Effects of ionizing radiation on retinoblastoma and on the normal ocular fundus in infants

This study is based on the experiences gained over a 20 year period (1963-83), where all cases of retinoblastoma in Denmark were treated by the authors. Fifty-seven children with 92 eyes affected by retinoblastoma were seen. Thirty-five children had bilateral retinoblastoma, while 22 had unilateral retinoblastoma. Among the unilateral cases, 20 eyes were primarily enucleated, 2 were irridiated but later excised. Among 35 children with bilateral retinoblastoma, 26 first eyes were primarily enucleated, while altogether 46 eyes were treated by ionizing radiation. The radiation treated cases were followed regularly by ophtalmoscopy, photography and flourescein angiography. The clinical appearance of the retinoblastoma and its response to radiation is described. Secondary tumours are localized more peripherally in the retina than the primary tumour. Early postradiation regression pattern are described and demonstrated to relate to tumour size, but not to retinal localization. A timetable is presented for the occurrence of radiation is presented for the occurrence of radiation induced changes, which in order of appearance comprise: calcification, tumour regression, snow-ball collaps, oedema around tumour, haemorrhage, ectatic vessels or neovascularization, vitreous haemorrhage and, eventually, recurrence of tumour. The post-radiation changes in the surrounding retina, choroid and optic nerve are reviewed and a timetable for the appearance of these changes presented. Radiation retinopathy comprises choriocapillary and pigment epithelium atrophy, retinal haemorrhage, exudates, papilloedema, peripapillar haemorrhage, subretinal exudates, narrow arteries, retinal eschemia, optic nerve atrophy, vascular ectasiae or proliferations and retinal detachment. (EG)