I did a prelim surgery intern year prior to starting ophthalmology - it's not for everyone, but here's some more thoughts for conversation.
It really depends on what you're looking to gain from your intern year. Just keep in mind this is really the last time you'll be taking full medical care of inpatients and doing more than just primarily outpatient and day surgery the rest of your life. Keep an open mind about your intern year in that it is an opportunity instead of just "a wasted year" prior to doing what we all really love doing - operating on eyes! Use it as an opportunity for doing things outside of medicine if you opt to go the cush route.
Full disclosure - I applied to a limited number of cush TY and community IM programs seeking a laid back year in a specific geographic region because like many others that post on SDN, I figured my QOL will be much better if I'm working 55-65 hrs/week instead of 75-85 hrs/week. Your QOL and attitude probably would be much better at the cush programs if you never considered having a busy residency/career. I almost applied to neurosurgery because I actually enjoy being in the operating room, waking up early and taking care of sick surgical patients much more than medical patients.
I didn't match into a cush TY program because I only ranked two competitive programs with great benefits that I thought I had a great chance of matching at and actually thought the residents enjoyed taking care of patients at these programs vs. the other places where everyone was just trying to do as little work as possible. I ended up at a prelim surgery program that I had looked into a fair amount prior to deciding on applying to just TY and IM programs. I never in a 100 years would have done an academic prelim IM program - you work 70-80 hours on average except clinic months at most of these programs and spend the vast majority of time writing notes, working on dispo issues and rarely get to do procedures. Surgery notes are brief, to the point and not a waste of time. Brief notes never killed anyone.
I totally agree that you will probably have more time to be a normal human and pass through the year like a 5th year of medical school doing a TY program in terms of pressure and amount of work. That was my thought too. As I interviewed and spoke with most residents at these programs, the sentiment was just that, try to get through the year doing as little as possible. That's OK IMO if this is your goal. It was my intention at first, but given certain location restrictions, plan B for me was prelim surgery at a place where I get to operate some if I didn't land a spot at the cush programs I actually liked. I was OK with doing a surgery year from the get go.
My year:
I definitely got to operate at my program, logged 135 cases, 30+ central lines, 25+ a-lines and about two dozen chest tubes. Also fixed numerous lacs in the ED and on trauma patients. Surgery residents were well respected at my program and I never felt any angst from my fellow residents or prelim residents. I became more at ease doing procedures with my hands, suturing, etc.
My fellow residents respected me for doing a surgery year, albeit out of necessity when I didn't formally apply for prelim surgery in the original match. I had my fair share of intern level cases (lap appys, lipoma excisions, vascular cath cases), but did some other great procedures like ORIF of ZMC fracture with plastics, several cranis with NSG on trauma patients, and multiple AV fistulas with transplant where you get you use vascular instruments commonly used in ophtho. I feel much more comfortable in the OR compared to my co-PGY2s who did medicine and TY programs. My PD has mentioned it several times.
Pros:
--There is an advantage of doing prelim surgery if you're doing ophtho - maybe not so much for derm or radiology (unless you want to do VIR).
--You will get to the OR at many of the programs for intern level cases. Seek out those programs - if you end up at a program with only scut work (e.g. Harvard/JHU gen surg), you will hate it. I have surgery friends at top programs who never get to operate (they do have fancy wet labs/training facilities, though) and were surprised how much I got to operate. Ask programs if they fill their prelim surg spots through the match or through a scramble?
--You will work hard - makes your transition to ophtho much more pleasant because you all the sudden have this extra time you didn't have last year.
--You see the difference between medicine and surgery. Enough said.
--Mild improvement in using non-dominant hand when operating. Really only noticed it in laparoscopic cases where I had to use both hands equally. Don't think that this is the main goal of the year.
--You learn to manage electrolytes, change antibiotic coverage as needed, hone physical exam skills, manage SICU patients just like medicine residents do for MICU patients. A lot of these intern learning objectives spread across all the specialties. I would rather learn how to make my skin closure more symmetric than the different classes of heart failure.
Cons:
--You work very hard and start before everyone else. The first few months were not fun in that regard. Then you get used to it and it was fine. I have a family and we adjusted. Again, makes you appreciate not having to get up at 4am anymore during your ophtho time even though I probably still get up very early because I got used to it last year.
--I averaged about 75 hours/week the entire year - I'm willing to bet my 75 hours were much busier than IM 75 hours. We didn't and couldn't cap our census, and often felt very exhausted. You'll have good days and bad days. you'll have good and bad weeks (several 55 hour weeks and several 90 hour weeks)
--You need to have a surgeon attitude if you want to consider prelim surgery. If you never got along with surgery residents in medical school, then it's not for you. You need to enjoy getting up early and taking care of surgical patients.
--The hierarchy in surgery is evident at every program. It's there because we operate and we do stuff in addition to taking care of floor patients. It can be a little upsetting when your chief or senior leaves you to manage the service at 2pm - don't know how often this happens in medicine but I will admit this happens often and will likely never change.
--Some programs differentiate prelims from categoricals - avoid these. Always ask if prelim residents get treated the same 100% or not.
In the end, most will not choose surgery because of inertia and because of lifestyl/QOL choices. I think it's an individual decision - don't think academic IM programs are laid back compared to surgery. They often put in as many hours, though they may be not as busy/stressful as the reputation surgery has. I valued my surgery year and think it has made me a better ophthalmology resident (may have little effect on the end outcome once practicing) at the very least than if I had done a TY. Decide if you would rather take care of a medical patient every morning or a surgical patient, and then find the program that will fit you and your educational needs. What you don't want is to end up at a program where you ONLY do floor work and see consults - because then it's basically like doing medicine but just busier.