The literature review was done, using Medline between 1966 and June 2002 and Embase between 1989 and 2002. Key words searched for were RON, acromegaly and radiotherapy as well as pituitary adenoma and radiotherapy. All papers that included acromegalic patients were checked for vision loss due to radiation therapy. The references retrieved by Medline and Embase were screened for other references, not found by using the abovementioned key words.
To estimate the incidence of RON in acromegaly we only included cohort series of patients, in which RON was taken into consideration. In case of a cohort of all kind of pituitary adenomas, it was only included in Table 1 in case of a known number of acromegalic patients, in which it was clear how many patients suffered RON. To evaluate risk factors for RON development we included RON-patients from series in which radiation treatment data were available, as well as individual case reports. This present survey includes our own series of 63 patients of whom two developed RON11.