Session: Free papers Session IV - Eye muscle surgery

Perfusion Monitoring in Real-Time During Strabismus Surgery with Laser Speckle Contrast Imaging

Anterior segment ischemia is a dreaded complication to strabismus surgery caused by damage to the anterior ciliary arteries. To reduce the risk, surgical protocols generally advocate that a maximum of two rectus muscles are detached at a time. However, these recommendations are not based on objective perfusion measurements but rather empirical observations of clinical outcome. We have used the non-invasive imaging tool Laser Speckle Contrast Imaging (LSCI) to capture perfusion in real-time during strabismus surgery, as wel as in enucleations to enable perfusion monitoring as all four rectus muscles are detached.



Data have been collected during 85 strabismus surgeries and 24 enucleations. Measurements on the iris- and paralimbal tissue was performed before- and after rectus muscle detachment and compared. 

 

The images vividly capture the perfusion of the anterior segment. Measurements following both horizontal- and vertical rectus muscle surgery revealed a decrease in perfusion, however the decrease was greater for the vertical muscle detachments. In the enucleations, perfusion remained relatively stable until the fourth rectus muscle was detached. Then, a pronounced and significant decrease was observed.  

 

This is the first time perfusion has been visualized in real-time during strabismus surgery. The larger decrease in perfusion in vertical rectus muscle detachment strengthen the clinical belief that vertical anterior ciliary arteries have a greater contribution to the perfusion of the anterior segment. The results from the enucleation study indicate that detachment of three rectus muscles in a surgical session may be feasible with little effect on anterior segment perfusion. Perioperative perfusion monitoring with LSCI has the potential to identify patients with a higher risk of anterior segment ischemia, which would enable tailored surgery. While future studies are needed, LSCI may be a valuable tool in reducing the risk of ASI following strabismus surgery.