Purpose: To determine the risk factors that influence the visual outco
mes of patients with macular retinoblastoma who are treated with radia
tion therapy. Methods: The medical records of all patients with macula
r retinoblastoma treated with radiation therapy between 1980 and 1990
were reviewed. Ten patients were entered into the study. Features anal
yzed included patient age, laterality of eye involvement, location and
size of macular tumor(s) at the time of diagnosis, treatment course,
and most recent visual acuity. Findings: Ten of 11 eyes (10 patients)
were successfully treated with external beam radiation. Eight patients
obtained Visual acuities ranging from 20/25 to 20/100; two patients h
ad visual acuities of 20/200 or less. The best visual acuities were no
ted in patients whose tumor(s) did not involve the fovea and were rela
tively small. The worse visual acuities were noted in patients with bi
nocular vision whose tumors invaded the fovea and were larger in size.
In two of three patients in whom both eyes were retained, superimpose
d amblyopia developed in the eye with macular retinoblastoma. Conclusi
on: The authors' findings indicate that most patients with macular ret
inoblastoma who are treated with external beam radiation have favorabl
e visual outcomes, but final visual acuity depends on the size of the
tumor and involvement of the fovea. Patients in whom both eyes are ret
ained are predisposed to further visual loss from amblyopia.