A health service corporation writing optometric service contracts may:
1. Enter into contracts with subscribers whereby each subscriber, subscriber member, officer, or employee is entitled to certain specified health services as provided in the subscriber's contract.
2. Enter into contracts with similar corporations within or without the state for the interchange of services to those included in subscription or other similar contracts, and may provide subscription contracts for the substitution of such services in lieu of those therein recited.
3. Enter into contracts with practitioners for the rendering of optometric service to subscribers in accordance with the terms of the subscriber contract.
4. Enter into contracts with optical laboratories to provide material pursuant to contracts with subscribers.