Purpose

To evaluate the effect of operating microscope use with coaxial illumination and magnification on field stability and vessel-sparing behavior in orbital fat decompression.

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Methods

This was a single-center retrospective study of consecutive patients undergoing bilateral microscope-assisted orbital fat decompression. Procedures were analyzed by predefined steps: anterior, extraconal, and intraconal fat dissection. Objective metrics included bipolar coagulation use, suction events, and field obstruction events, defined as interruption of the surgical view due to bleeding, shadowing, or instrument interference. Outcomes included operative time, proptosis reduction, retrobulbar hemorrhage, new-onset diplopia, and visual acuity change.

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Results

A total of 34 patients (68 orbits) were included. Bipolar coagulation was used 3.0 ± 0.70 times per orbit during anterior fat dissection without clamping and 0.30 ± 0.50 times per orbit in the extraconal space. No hemostatic intervention was required within the intraconal space. Minor extraconal bleeding was controlled with epinephrine-soaked gauze. Suction was required 2.1 ± 0.80 times per orbit, and field obstruction events were 1.4 ± 0.60 per orbit. No bleeding requiring intervention or retrobulbar hemorrhage occurred. Mean operative time was 23.8 ± 3.4 minutes per orbit, and mean proptosis reduction was 3.1 ± 0.40 mm. No new-onset diplopia or visual acuity deterioration was observed.

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Conclusion

The operating microscope provides coaxial illumination and magnification, enabling a stable, shadow-reduced field. This allows gradual loosening and selective fat removal without clamping, facilitating avoidance of critical vascular structures. The absence of intraconal hemostatic intervention and limited need for suction and coagulation suggest a vessel-sparing strategy based on bleeding avoidance rather than reactive hemostasis. These findings indicate that microscope-assisted orbital fat decompression improves field stability and surgical safety while achieving outcomes comparable to previous reports.

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Additional Authors

First name	Last name	Base Hospital / Institution
Tomoyuki	Kashima	Oculo Facial Clinic Group

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