Now that the ADAAA has been enacted, can former employee apply it retroactively?

Q. One of our security employees uses a hearing aid. He could not pass the unaided hearing requirements of his job. As a result, we let him go. His layoff occurred in 2007, when he first brought a claim for an alleged violation of the ADA. He claims that with the subsequent adoption of the ADA Amendments Act of 2008 (ADAAA), an employer is not allowed to consider mitigating measures in determining whether an employee has a disability. Can the ADAAA be retroactively applied so he is deemed to have a disability under the ADA?