VISUAL OUTCOMES OF MACULAR RETINOBLASTOMA AFTER EXTERNAL-BEAM RADIATION-THERAPY

Purpose: To determine the risk factors that influence the visual outcomes of patients with macular retinoblastoma who are treated with radiation therapy. Methods: The medical records of all patients with macular retinoblastoma treated with radiation therapy between 1980 and 1990 were reviewed. Ten patients were entered into the study. Features analyzed 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 had visual acuities of 20/200 or less. The best visual acuities were noted in patients whose tumor(s) did not involve the fovea and were relatively small. The worse visual acuities were noted in patients with binocular vision whose tumors invaded the fovea and were larger in size. In two of three patients in whom both eyes were retained, superimposed amblyopia developed in the eye with macular retinoblastoma. Conclusion: The authors' findings indicate that most patients with macular retinoblastoma who are treated with external beam radiation have favorable visual outcomes, but final visual acuity depends on the size of the tumor and involvement of the fovea. Patients in whom both eyes are retained are predisposed to further visual loss from amblyopia.