From what I have heard it is harder as a DO to get an allopathic ophthalmology residency. Furthermore, there are only a few DO residencies out there for this specialty. However, never lose faith and go after what moves you. DO students do get ophthalmology residencies. A student from NYCOM matched into an allopathic residency and I know 1 or 2 matched from KCOM (my school), and I am sure a couple more matched from the other DO schools such as PCOM, MSUCOM, OUCOM, OSUCOM..etc. In fact, the DO that interviewed me at KCOM was an ophthalmologist. Therefore, it seems possible although a bit harder. The general consensus is that a student definitely has to take the USMLE and do very well on it, research is always a big plus, do great during rotations, get good letters of rec., do audition rotations at an institution that you are interested in and impress them, and keep those fingers crossed. Remember, ophthalmology is hard to get even for MD students. There are many well qualified MD students that do not get a position. Keep the faith!