Background A dreaded complication of strabismus surgery is anterior segment ischaemia (ASI), caused by damage to the anterior ciliary arteries. To avoid ASI, a maximum of two rectus muscles are operated on at a time. However, these surgical protocols are based on empirical observations of clinical outcome, rather than objective perfusion measurements. There is no method available for perioperative, real-time perfusion measurements during ocular muscle surgery. The aims of this study were to investigate whether laser speckle contrast imaging (LSCI) could be used for such measurements, and to monitor perfusion during strabismus surgery on one or two horizontal rectus muscles.
Methods Forty-four eyes in 44 patients with horizontal strabismus underwent corrective surgery involving medial and/or lateral rectus muscle detachment. Perfusion in the adjacent paralimbal and iris tissue was monitored with LSCI.
Results When the first horizontal rectus muscle was detached perfusion in the adjacent paralimbal tissue decreased by 23% (p<0.0001), and by 12% (p<0.0001) when the second muscle was detached. The iris perfusion decreased by 5% (p<0.05) when the first muscle was detached but showed no significant decrease as the second muscle was cut.
Conclusion This is the first study showing that perfusion of the anterior segment can be monitored non-invasively with LSCI during strabismus surgery. In this cohort, two horizontal rectus muscles were detached with only a small decrease in the anterior segment circulation. Future studies are required for complete mapping of the effect of surgery on multiple ocular muscles on the anterior segment circulation.
Data availability statement
Data are available upon request.
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Contributors LE: data acquisition and analysis, preparation of manuscript. RS and SL: conception of the study, data analysis. JA: data acquisition and analysis. JB: data acquisition, interpretation of data. UD: conception of the study, manuscript revision, responsible for the overall content as guarantor.
Funding This study was supported by the Swedish Government Grant for Clinical Research (ALF, 2021-UD), Skåne University Hospital Research Grants (2020-RS), Skåne County Council Research Grants (2020-0299), Crown Princess Margaret’s Foundation (KMA, 2021-022), the Foundation for the Visually Impaired in the County of Malmöhus (2021-UD), the Swedish Eye Foundation (2021-RS) and Carmen & Bertil Regnér’s Foundation (2020-00058).
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.