With reference to the article on scleral complications following beta irradiation by Moriarty et al1 in the July 1993 issue of the Archives, I was surprised to note that there was no mention of the surface areas exposed to beta radiation in the affected patients. Both area and dosage are important measurements in radiotherapy. This is paricularly so when treating scleral tissue that, because of its relative avascularity, is particularly vulnerable to radiation-induced ischemia.
As I stated in the letter2 cited by the authors, I have been using beta radiation in pterygium surgery for more than 20 years and have not had any scleral complications. My dosages are similar to those reported by Moriarty et al1 and I use a kidney-shaped applicator measuring 3.0×8.5 mm (approximately 26 mm2 in area), placed at the limbus.
The recent retrospective series by MacKenzie et al3 referred to by
Levine DJ. Scleral Complications Following Beta Irradiation. Arch Ophthalmol. 1994;112(8):1016. doi:10.1001/archopht.1994.01090200018003