Influence of Biometric Data on Planning Strabismus Surgery.

Purpose: To evaluate the influence of optical biometry data (axial eye length, anterior chamber depth) on planning strabismus surgery using a simulation software and partial least squares regression. Methods: This retrospective study included patients who had undergone strabismus surgery in one eye involving only the horizontal eye muscles. Furthermore, optical biometry had been performed and the extent of strabismus had been measured pre- and postoperatively. In the next step the strabismus surgery was simulated (See++, RISC, Austria) with and without axial eye length data. In the last step, anatomical data of the eye were used and their influence on the postoperative extent of strabismus was evaluated using partial least squares regression and boot strapping. Results: Of 97 patients, 92 were included in the analysis. In all cases the extent of strabismus was reduced by at least 25% and in 60% of the cases the reduction was at least 75%. Taking the axial eye length into account improved the simulation slightly (change of surgical planning: 0.30 mm, standard deviation 1.65 mm). Discussion: The simulation model used showed that including the axial eye length is useful for strabismus surgery planning. However, the anterior chamber depth/axial eye length was found to have a significantly greater impact.