Purpose

To evaluate the incidence, characteristics, and resolution of diplopia after orbital decompression in patients with thyroid eye disease and to assess the effect of surgical approach and disease-related factors.

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Methods

This single-center study included 49 eyes, of 27 patients (18 female, 9 male), with a mean age of 51,50 ± 12,70 years. Preoperative CT imaging, pre- and post-operative orthoptic assessment including Hess chart, and clinical data were reviewed. Patients underwent external (70,37%), endonasal (18,52%), or combined (11,11%) orbital decompression. Multi-wall decompression was performed in 66,67%, and single-wall in 33,33%. Mean follow-up was 18,96 ± 14,96 months.

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Results

Persistent diplopia occurred in 18,52%, while 7,41% developed a new-onset diplopia after the surgery. Among the patients with preoperative diplopia, 71.43% had persistent symptoms in the early postoperative period, whereas 28.57% experienced resolution within the first postoperative months. Persistent diplopia occurred only after multi-wall decompression, most often three-wall surgery (33,33%), whereas new-onset double vision occurred only after a single lateral wall decompression. Double vision rates were 26,32% in external, 20,00% in endonasal, and 33,33% in combined procedures. Persistent diplopia was associated with higher apical crowding scores (p = 0,021) and vertical muscle index (p = 0,041). Superior rectus thickness was higher in these patients but not statistically significant (p = 0.067). Persistent and new-onset diplopia were not associated with surgical approach or decompression type (all p > 0.05).

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Conclusion

New-onset diplopia was uncommon post-operatively. Pre-existing diplopia resolved in all patients during follow-up without the need for strabismus surgery. Persistent postoperative diplopia was associated with apical crowding and vertical muscle involvement, whereas surgical approach and decompression type were not. Risk stratification therefore relies on careful preoperative CT evaluation and detailed orthoptic assessment, rather than surgery type.

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Additional Authors

First name	Last name	Base Hospital / Institution
Priyancaa	Jeyabaladevan	Royal Free NHS Foundation Trust
Michelle	Ting	Royal Free NHS Foundation Trust
Nikolas	Koutroumanos	Royal Free NHS Foundation Trust
Hugo	Henderson	Royal Free NHS Foundation Trust

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