To encourage people to assign their Medicare benefits to an HMO, many HMO's offer additional ancillary benefits like vision and prescription benefits. Medicare and HMO's are designed to pay for acute medical care needs. They pay for short term, rehabilitative care. This type of care is provided by licensed professionals. It is also called skilled care.
Skilled care is determined by the types of services a person receives.
An example would be physical therapy after a stroke, or IV therapy. Medicare pays for care in skilled nursing facilities, and for home health care. Medicare does not pay for long-term care. Long-term care is when people need assistance with activities of daily living or supervisions due to a cognitive impairment. Medicare was not designed to cover chronic conditions.