Inferior rectus muscle detachment during strabismus surgery has a major effect on anterior segment perfusion, as shown by LSCI perfusion monitoring.

Background: Anterior segment ischaemia (ASI) is a rare but feared complication associated with strabismus surgery, arising from damage of the anterior ciliary arteries that run along the extraocular rectus muscles. It has been reported that the risk of ASI following strabismus surgery increases when the vertical rectus muscles are involved. The aim of the present study was to monitor anterior segment perfusion in real time during inferior rectus muscle surgery.

Methods: 17 eyes in 16 patients undergoing surgery on the inferior rectus muscle were included. Perfusion was measured in the adjacent paralimbal and iris tissue, before and after inferior rectus muscle detachment, using laser speckle contrast imaging.

Results: The paralimbal vascular network was clearly visualised in the perfusion images, whereas the signals from the iris were lower. Detachment of the inferior rectus muscle resulted in a reduction in paralimbal and iris perfusion by a median of 33% (p<0.0001) and 11% (p=0.0174), respectively.

Conclusion: Strabismus surgery involving the inferior rectus muscle significantly affects perfusion to the anterior segment, and to a greater extent than previously observed following surgery on horizontal rectus muscles (where the decrease was only 23% and 5%).