This paper presents a robustness-enhanced adaptive control scheme and application to an experiment for the focusing of an optical read-write head for optical data storage drives. Minimum-variance adaptive controllers have applied recursive least-squares algorithms to predict output disturbance and dynamically compute control commands to minimize the output error. This existing adaptive control could become unstable when significant modeling errors and uncertainties exist. An extension is made to the existent adaptive control scheme to achieve robust stability while minimally sacrificing the control performance. Simulation and experiment conducted on the optical focusing of a digital video recording drive's read-write head demonstrate that the proposed robustness enhancement adaptive control scheme is effective in achieving stability and performance while the existing adaptive control fails.