Surgical management in the treatment of heavy eye syndrome: Success of myopexia alone without surgery for the medial rectus

Abstract Body:

Purpose: Esotropia and Hypotropia associated with high myopia is called Heavy eye syndrome (HES), also known as myopic strabismus fixus. In recent years, myopexy and its variations (loop myopexia, lateral rectus repositioning) have become excellent of choice in the surgical management of Heavy eye syndrome. Given the increasing use of these techniques in the treatment of HES, our study aims to evaluate the efficacy of myopexy alone with no intervention with regards to extraocular muscle insertion in the treatment of HES.

Study Design: This study is a retrospective cohort series following patients diagnosed and treated for Heavy eye syndrome at a major tertiary pediatric ophthalmology practice in Edmonton, Alberta, Canada, between 2009 and 2017. REB Approval was obtained prior to evaluation of charts.

Methods: Patient charts with clinical features of high myopia associated with esotropia and hypotropia, as well as MRI or CT findings characteristic of Heavy eye syndrome were identified and extracted. This process yielded nine patients and 15 eyes that met inclusion criteria. Data collected in this study includes age, sex, pre-operative and post-operative eye alignment, pre-operative refraction, limitation of abduction and elevation pre and post-operatively. Means and 95% confidence intervals were calculated for each variable. Statistical analyses of patient data were conducted using paired T-test analysis for comparison of groups.

Results: The majority of HES eyes which underwent surgical correction were treated with myopexy (64%), followed by loop myopexy (21%), and repositioning of the lateral rectus (14%). These procedures corrected a mean of 27.6 prism diopters in the horizontal plane (2.62 SD, 20.29 -30.90 CI) and 5.6 prism diopters of hypotropia in the vertical plane (6.11 SD, -7.98 -1.21 CI). Of these cases, post-operative surgical correction in the vertical (p-value 0.0113) and horizontal (p-value <0.0001) plane were found to be statistically significant comparing pre and post-operative measurements. There is also improvement in the limitation of elevation (p-value 0.0263). A minority of patients (26%) were found to be over-corrected following surgery. Post-operative complications associated with overcorrection occurred primarily in the vertical direction.

Conclusions: Myopexy was found to be the most commonly used surgical method for correction of strabismus associated with HES. Myopexia is shown to be effective in decreasing the degree of deviation in both the horizontal and vertical directions. Post-surgical overcorrection was the primary complication of surgical management and occurred mostly in the vertical direction with limitation in depression following the procedure.