Here is a portion of a BVA decision which deals with the question:
The veteran argues that an earlier effective date is
warranted for his left ear tinnitus because he did not have
this condition prior to service and was service-connected for
hearing loss of the left ear with the effective date of
September 10, 1993. The veteran also contends the notation
of unilateral tinnitus of the left ear in the October 1993 VA
examination supports his contentions, implying that VA should
have interpreted the examination as a claim for service
connection. As such, he maintains that the effective date of
service connection for the tinnitus should be retroactive to
the hearing loss effective date of September 10, 1993.
The basic facts are not in dispute. As the RO noted, the
veteran's initial formal or informal application for service
connection for left ear tinnitus was filed with VA on
September 30, 2005, and indeed, the veteran does not contend
otherwise.
Unless specifically provided otherwise in the statute, the
effective date of an award based on an original claim for
compensation benefits shall be the date of receipt of the
claim or the date entitlement arose, whichever is later.
38 U.S.C.A. § 5110(a); 38 C.F.R. § 3.400. The effective date
of an award of disability compensation shall be the day
following separation from service or the date entitlement
arose if the claim is received within one year of separation,
otherwise the date of claim or the date entitlement arose,
whichever is later. 38 U.S.C.A. § 5110(:D; 38 C.F.R.
§ 3.400(B)(2).
A specific claim in the form prescribed by the Secretary must
be filed in order for benefits to be paid or furnished to any
individual under the laws administered by VA. 38 U.S.C.A.
§ 5101(a); 38 C.F.R. § 3.151(a). The term "claim" or
"application" means a formal or informal communication in
writing requesting a determination of entitlement or
evidencing a belief in entitlement to a benefit. 38 C.F.R.
§ 3.1(p).
Any communication or action indicating an intent to apply for
one or more benefits under the laws administered by VA, from
a veteran or his representative, may be considered an
informal claim. Such informal claim must identify the
benefit sought. Upon receipt of an informal claim, if a
formal claim has not been filed, an application form will be
forwarded to the claimant for execution. If received within
one year from the date it was sent to the veteran, it will be
considered filed as of the date of receipt of the informal
claim. 38 C.F.R. § 3.155.
Here, the RO granted service connection for the left ear and
assigned a 10 percent evaluation, effective September 30,
2005, the date the veteran's original claim of service
connection for tinnitus was filed with VA. An effective date
of an award of service connection is not based on the
earliest medical evidence showing a causal connection as the
veteran contended through his representative, but on the date
that the application upon which service connection was
eventually awarded was filed with VA. Lalonde v. West, 12
Vet. App. 377, 382 (1999).