Spontaneous polar anterior subcapsular lenticular opacity in Sprague-Dawley rats

A spontaneous focal polar anterior subcapsular lenticular opacity character ized by focal epithelial proliferation was found in Charles River Sprague-D awley rats from various breeding facilities around the world (France, Japan , and the United States). The incidence of this change slightly increased w ith age up to a maximal incidence of 9.8% in 28- to 35-week-old male rats ( French source). Over that period, there was little change in the size of th e opacity; however some rats that were examined over longer periods (more t han 2 years of age) developed secondary anterior cortical changes, and rare ly histologic findings of pigmentation and/or mineralization. The lenticula r change was present throughout the life of the animals and had no sex pred ilection; mode of inheritance was not investigated, Due to its small size, this lens opacity is more easily identified by use of slit lamp biomicrosco py than by use of indirect ophthalmoscopy, and serial sections of the eye a id in locating it for histologic evaluation.