Application of 3D biomechanical eye model for concomitant strabismus diagnostics and treatment

Abstract

Abstract Purpose Due to inaccuracy of diagnostic tests, prevalence of orthotropy after the first strabismus surgery varies in the range of 40 to 90%, and frequency of repeated surgeries comprises 10–50%. The purpose of the study was to investigate the efficacy of using of 3D biomechanical eye model (TBEM) in diagnostics and treatment of patients with concomitant strabismus (CS). Methods 30 CS patients were examined and underwent standard strabometric tests (Hirschberg test, Krymskiy test, Maddox scale, synoptophore with fusion reserves). Hyperfunction and hypofunction of one muscle or another was measured by coordimetry according to Hess‐Lancaster; modeling of eye positions was performed using SEE‐KID 3D biomechanical model (RISC Software GmbH, Hagenberg, Austria). Standard surgeries were performed on the basis of their pre‐surgical modeling in SEE‐KID TBEM. Exclusion criteria: patients with high and moderate amblyopia were excluded from the study. Follow‐up period comprised 1 – 3 months. Results Virtual pathological models created using SEE‐KID TBEM for all examined patients conformed to their actual strabismologic status. Surgeries conducted on the basis of preliminary TBEM modeling have resulted in achievement of orthotropy in 20 patients (66.7%) and its preservation at last visit in follow‐up period. Residual strabismus angle (5‐8°) was detected in 10 patients, including hypocorrection (9 patients), and hypercorrection (1 patient). Conclusion The use of existing strabometric methods in complex with TBEM is a promising diagnostic algorithm for assessment of the state of concomitant strabismus patients, which requires further studies.