Welcome to the forum!
Ophthalmology and Neurosurgery are very different fields imho. In Neurosurgery, you are dealing with often life-threatening issues. While in Ophthalmology, it is generally about improving a person's quality of life. Because of the differences in responsibility, there is a huge difference in stress levels between the two fields. Some people feed off of this stress/adrenaline especially when it is brand-new to them (e.g. during medical school). But what you really need to ask yourself is this: "what type of daily/weekly life will make me truly happy in the long-run?" For some individuals, they cannot imagine doing anything besides neurosurgery or cardiothoracic surgery. For me personally, I couldn't imagine doing 6 hour long cases and then rounding on patients in the hospital afterwards. I would much rather operate or see patients in clinic for 35-40 hours a week and then spend my ample free time with my family or pursuing my other passions in life. Trust me: all jobs will become routine after awhile. You want to make sure that the worst part of your job is bearable.
There are many Ophthalmologists out there that operate several days a week, but this is probably not the "average" Ophthalmologist. You have to remember that most mid-career Ophthalmologists can feasibly do 20-30 cases a day. Thus, it is not efficient to spread those 20-30 cases over multiple OR days, since OR time is very expensive (especially if you own the OR!). It is more cost-effective to stack all of your cases in one day if possible because you can perform those 20-30 cases much more efficiently. Hint: efficiency == more $$ that you take home (instead of spending those $$ in staff wages). Since an average Neurosurgery case can last several hours, you can only do a few cases a day at most. That is the reason they may be in the OR several days a week. I don't think Neurosurgeons are doing 30 craniotomies or whatever per day!
If you are worried about $, please don't be. Those Medscape surveys are very skewed to people who actually fill them out. Most of my colleagues in private practice make in the high 6-digit area while a significant number of them make 7-digits. We even have friends in the ~3MM/year stratosphere working 4 days/week, but they are in a very fortuitous situation. After a certain point, saving another million dollars is not going to bring you significantly more happiness. But having quality time to spend with your friends & family will make a huge difference with your happiness as you get older.
I think the biggest service you could do for yourself is to spend some time shadowing several private practice physicians in both Ophthalmology and Neurosurgery, and really see who is happier. Don't forget to ask about their work-life balance. Best of luck!