((a)) ** .—** Each of the following officers is entitled to special pay at the rate of $100 a month for each month of active duty:
((1)) A commissioned officer—
((A)) of the Regular Army, Regular Navy, or Regular Air Force who is designated as an optometry officer; or
((B)) who is an optometry officer of the Regular Corps of the Public Health Service.
((2)) A commissioned officer—
((A)) of a Reserve component of the Army, Navy, or Air Force who is designated as an optometry officer; or
((B)) who is an optometry officer of the Reserve Corps of the Public Health Service,
((3)) A general officer of the Army or the Air Force appointed, from any of the categories named in clause (1) or (2), in the Army, Air Force, or the National Guard, as the case may be.
((b)) ** .—**
((1)) Under regulations prescribed under , the Secretary concerned may pay an officer described in paragraph (2) a retention special pay of not more than $15,000 for any twelve-month period during which the officer is not undergoing an internship or initial residency training.
((2)) An officer referred to in paragraph (1) is an officer of a uniformed service who—
((A)) is entitled to special pay under subsection (a);
((B)) has completed any initial active-duty service commitment incurred for education and training; and
((C)) is determined by the Secretary concerned to be qualified as an optometrist.
((3)) An officer may not be paid retention special pay under paragraph (1) for any twelve-month period unless the officer first executes a written agreement under which the officer agrees to remain on active duty for a period of not less than one year beginning on the date the officer accepts the award of such special pay.
((4)) The Secretary concerned may terminate at any time the eligibility of an officer to receive retention special pay under paragraph (1). An officer who does not complete the period for which the payment was made under paragraph (1) shall be subject to the repayment provisions of .