Here is a web site that might be able to help with a free eye exam. I'm not sure what the income guidelines are.

http://www.aoa.org/visionusa.xml

If you do not qualify for government aid or private health care assistance that covers the cost of routine eye or vision care, Vision USA™ can help. Vision USA™ provides basic eye health and vision care services free of charge to uninsured, low-income people and their families. Vision USA™ was established in 1991 by AOA doctors of optometry who donate their services.
Eligibility Requirements


Vision USA™ is open to children and adults. General eligibility requirements vary by state. To receive free services, you must:
  1. Have a job or live in a household where there is one working member
  2. Have no vision insurance (this may include Medicare/Medicaid)
  3. Have income below an established level based on household size
  4. Not have had an eye exam within two years
If you or your family are eligible to receive services, you will be matched with a volunteer doctor of optometry who will provide a comprehensive eye exam at no charge. Eyewear also may be provided at no cost or for a small fee/donation in some states. (Note: Doctors donate their services and may be limited in some areas.)