  Recently, Gaiotto, Moore and Neitzke \cite{GMN08} proposed a new construction
of hyperk\"{a}hler metrics. In particular, they gave a new construction of the
Ooguri-Vafa metric, in which they came across certain formulas. We interpret
those formulas as wall-crossing formulas that appear in the SYZ construction of
instanton-corrected mirror manifolds. This reveals the close relation between
the Ooguri-Vafa metric and nontrivial holomorphic discs with boundary in
special Lagrangian torus fibers.
