You're still in the middle of the process, and there is still time to get more interviews. SDN is a great resource to know when programs are sending out invitations, but don't get bogged down by the success of others. My last interview invitation came the second week of November a couple cycles back. What are your goals? Just to match? If you want to just match, then go through the process, take as many interviews as you can, make your rank list, and see if you match. If you are deadset on a certain region or list of programs that don't offer you an interview, then perhaps taking a year off to improve your application would be beneficial. I would imagine you would have to do a lot to go from not being offered an interview to being ranked high enough to match, so be cautious about that decision. For ophthalmology, you do have to have realistic expectations for matching due to its competitive nature, so it can be difficult to guarantee a particular region or program. I haven't known anyone who has started the process, but withdrawn halfway through. If you're set on ophthalmology and are willing to try again if you don't match, then I would say don't apply for a back-up specialty yet. You can withdraw your ERAS application if you don't match ophthalmology. Hang in there! It's worth it.
