Posterior staphyloma, as the diagnosis itslef explains, involves the posterior segment of the eye, typically diagnosed at the region of the macula. Relative pathology provokes deformation of the eye in a way that the eye-length is extended with associated myopia.. It is diagnosed by ophthalmoscopy, which shows an area of retinal excavation in the region of the staphyloma. Concerning visual field defects, you can find some good references in:
Kyoko Ohno-Matsui, Noriaki Shimada, Kenjiro Yasuzumi, Kengo Hayashi, Takeshi Yoshida, Ariko Kojima, Muka Moriyama, Takashi Tokoro Long-term Development of Significant Visual Field Defects in Highly Myopic Eyes American Journal of Ophthalmology,Volume 152, Issue 2, August 2011, Pages 256–265.e1
Young Hoon Hwang, Chungkwon Yoo, Yong Yeon Kim Long-term Development of Significant Visual Field Defects in Highly Myopic Eyes American Journal of Ophthalmology, Volume 152, Issue 5, November 2011, Pages 878-879