The last question is an interesting one. What would an ACO-owned eye service look like, if such a thing were to be created? My guess is that it would resemble something much more like a Kaiser Permanante closed-panel HMO than a traditional academic or multispecialty ophthalmology practice. The bulk of routine medical eyecare would be delegated to optometrists with referral to a handful of general ophthalmologists and outside referral would be limited to a handful of contracted subspecialists not on the ACO payroll (but who may be competitively bid out.) The ACO wants to handle as much as possible within the organization and do so in the lowest-cost way. The ophthalmologists would be doing mostly surgery, but as little followup as possible, delegating most of that care to the optometric staff if possible. Efficiency and "optimization" of resources would probably require "bending" the traditional notion of the surgeon overseeing the entire pre-intra-post-operative care cycle.
The ACO idea is nothing more than capitated managed care for Medicare, with the risk (and supposed "rewards" ) being assigned to the ACO. The hard truth is that the future will mean progressive lowering of the payments, and the basis for doing so will be data mining-driven analysis of patient cohorts defined by elaborated ICD-10 codes and CPT codes for treatments and services. You can bet that the payment for a cohort of beneficiaries will be lowered to whatever the lowest decile of costs/services that don't result in a statistically-significant increase in new ICD-10 descriptors of complications, and that analysis will be run over and over seeking ever more minimal patterns of expenditures that don't lead to more problems, and that will be the payment benchmark. This is how the CMS will be getting around the regional variations in utilization of services; they will stop paying for anything more than whatever care results in no signigicant ICD-defined increase in occurrence of disease-associated diagnoses. The costs of exceeding that minimum standard will be borne by the ACO, which will be under significant pressure to conform.