Corneal and astigmatic changes after medial rectus recession surgery of 6mm
Reviewed by Fiona Rowe

This study prospectively compared changes in astigmatism before and two months after unilateral recession of medial rectus muscles using Pentacam. The fellow unoperated eye was used as the control eye. The study included 66 eyes and 33 patients; 21 males, 12 females with mean age at surgery of 7.9 years (SD2.49). Patients were divided to three groups based on central corneal thickness (CCT): group a (n=9) with CCT ≤540um, b (n=10) with CCT of 541–570um and c (n=14) with CCT ≥571um. Patients were also divided to three groups based on age: group 1 (n=9) ≤6 years, 2 (n=13) aged 6–9 years, and 3 (n=11) aged ≥9 years. There was no association for CCT values in groups a to c or for age groups 1–3. Surgical groups and changes in anterior corneal surface astigmatism were significant as were changes in posterior corneal surface astigmatism. However, these were not clinically significant. There were significantly lower values postoperatively for radius of axial curvature of vertical meridian at 3 and 3.5mm inferiorly from the optical corneal apex, and in the radius of the axial curvature of the vertical meridian at 3mm superior from the optical corneal apex. There were no significant changes for any variable in the control eyes. The authors conclude medial rectus recession surgery appears to be associated with changes in astigmatism which specifically include horizontal flattening on axial / sagittal front curvature Pentacam maps and vertical steepening consistent with increase in with-the-rule astigmatism. They recommend avoidance of large medial rectus recession single muscle surgery with choice, instead, of smaller recession / resection surgery. However, in eyes with against-the-rule astigmatism, they recommend large medial rectus recessions to decrease the pre-existent astigmatism. They acknowledge their study limitations of two-month follow-up and note further study is required with longer-term follow-up to evaluate whether these corneal / astigmatic changes persist.

Corneal tomography changes following major (6mm) medial rectus muscle recessions: a prospective cohort study using Pentacam.
Paraskevopoulos K, Karakosta C, Feretzakis G, et al.
STRABISMUS
2024;32(1):39–47.