. Retinal pigment epithelial transplantation in exudative age-related macular degeneration: what do invivo and in vitro studies teach us?

摘要

Subfoveal choroidal neovascularization remains a leading cause of severe visual loss in patients with age-related macular degeneration (AMD). Unfortunately, most patients who develop choroidal neovascularization in AMD have subfoveal choroidal neovascularization at the time of presentation, or ill-defined choroidal neovascularization which is not readily amenable to laser treatment. Studies of the natural history of subfoveal choroidal neovascularization in AMD indicate that 70% of eyes achieve a visual acuity of 20/200 (6/60) or worse within 2 years of presentation. In 1991, the Macular Photocoagulation Study group demonstrated a treatment benefit of laser photocoagulation compared with no treatment for a select subgroup of eyes with subfoveal choroidal neovascularization associated with AMD, but there is a significant postoperative reduction in visual acuity which is an unavoidable consequence of subfoveal laser photocoagulation. In addition, 51% of eyes with subfoveal membranes in AMD demonstrate persistent or recurrent choroidal neovascularization by 24 months after treatment.Because of these limitations, several workers have developed and refined the techniques necessary for surgical excision of subfoveal choroidal neovascular membranes in AMD, presumed ocular histoplasmosis syndrome (POHS), and other miscellaneous disorders5"11. In 1991, Thomas and Kaplan reported two patients with subfoveal neovascular membranes and POHS who improved dramatically to 20/20 and 20/40 vision after surgical excision of subfoveal choroidal neovascularization5. Extension of these techniques to patients with choroidal neovascularization secondary to AMD has met with more limited success.