The authors used wide field swept-source OCT angiography (SSOCTA) to evaluate changes in retinal and choroidal blood flow before and after horizontal rectus muscle surgery. They aimed to characterise the haemodynamic impact of extraocular muscle surgery on the posterior pole and explore the spatial and temporal patterns of vascular response. The study involved 124 patients split into two groups: (1) 59 with unilateral single muscle recession; mean age 15.10 ±10.01 years, 28 male, 31 female, and (2) 65 with unilateral recession/resection surgery; mean age 11.88 ±6.55 years, 32 male, 33 female. Overall, transient and region-specific changes occurred in retinal and choroidal circulation. Most parameters were stable across timepoints but some significant changes were seen at 1 week postoperatively which largely resolved by 1 month, i.e. temporary vascular responses. Main variations were in the deep capillary plexus, choroidal thickness, choroidal vascular volume, and choriocapillaris perfusion and primarily in the peripheral retina. Group 2 showed greater and widespread changes than group 1. Overall, there were greater responses in choroidal parameters than retinal, with relative sparing of central fovea and main changes in peripheral retina. Greater changes were after lateral rectus surgery than the medial rectus. This is possibly explained by the proximity to the posterior pole and the course of short posterior ciliary arteries and vortex veins. Therefore posterior circulation may be more susceptible to surgical manipulation. In addition, disruption of the single ciliary artery supply to the lateral rectus may cause greater local perfusion imbalance. The authors suggest these findings may be used to inform surgical planning by highlighting vulnerable vascular regions, especially for patients with presenting ocular vascular compromise.
Choroidal and retinal vascular changes after horizontal rectus surgery
Reviewed by Fiona Rowe
Influence of strabismus surgery on fundus hemodynamics based on swept-source OCT angiography blood flow parameters.
CONTRIBUTOR
Fiona Rowe (Prof)
Institute of Population Health, University of Liverpool, UK.
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