James B. Criswell appeals the judgment of the United States Court of Appeals for Veterans Claims, which affirmed the Board of Veterans’ Appeals decision denying his claim for an effective date prior to August 21, 1997, for a 50% combined disability rating for his service-connected cold-injury residuals of the hands and feet. Criswell v. Nicholson, 20 Vet.App. 501 (2006). Because we lack authority to review either “a challenge to a factual determination” or “a challenge to a law or regulation as applied to the facts of a particular case” absent a constitutional issue, 38 U.S.C. § 7292(d)(2), we dismiss his appeal.