According to the US Department of Labor:
Audiologist:
Median annual earnings of audiologists were $48,400 in 2002. The middle 50 percent earned between $39,510 and $58,430. The lowest 10 percent earned less than $32,500, and the highest 10 percent earned more than $73,130.
According to a 2003 survey by the American Speech-Language-Hearing Association, the median annual salary for full-time certified audiologists who worked on a calendar-year basis, generally 11 or 12 months annually, was $52,000. For those who worked on an academic-year basis, usually 9 or 10 months annually, the median annual salary was $47,500. The median starting salary for certified audiologists with one to three years experience was $43,000 on a calendar-year basis. Certified audiologists who worked 25 or fewer hours per week had a median hourly salary of $28.00.
Optometrist:
Median annual earnings of salaried optometrists were $86,090 in 2002. The middle 50 percent earned between $62,030 and $115,550. Median annual earnings of salaried optometrists in 2002 were $87,070 in offices of other health practitioners. Salaried optometrists tend to earn more initially than do optometrists who set up their own independent practice. In the long run, however, those in private practice usually earn more.
According to the American Optometric Association, median net annual income for all optometrists, including the self-employed, was $110,000 in 2002. The middle 50 percent earned between $82,500 and $156,500.
Also, this web site stated that in 2 states, you are not required to have license to practice audiology and of those 48, 12 do not require CE.