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Published on: March 1, 2015
Surgical Management of Masquerading Superior Oblique Palsy
Qingyu Meng1, Veronika Yehezkeli2, Joseph L Demer3
1Stein Eye Institute and Department of Ophthalmology, University of California, Los Angeles (Q.M., V.Y., J.L.D.), Los Angeles, California, USA; Department of Ophthalmology, Peking University People's Hospital (Q.M.), Beijing, China.
Purpose:
To compare the surgical outcomes between superior oblique (SO) palsy (SOP) and masquerading SO palsy (mSOP).
Design:
Comparative interventional case series.
Methods:
Medical records of patients with SOP and mSOP were reviewed from 1991 to 2024. Palsy cases had maximum SO cross section in the hypertropic eye no more than 80% of that in the fellow eye, whereas mSOP cases had bilaterally symmetric SO muscles on magnetic resonance imaging. Types of surgery and effect on hypertropia were compared between groups.
Result:
A total of 39 patients aged 38±20 (standard deviation) years had SOP and 18 aged 36±17 years had mSOP. Maximum palsied SO cross section was 10.6±3.8 mm2, significantly smaller than 18.9±4.0 mm2 of the contralateral fellow (P < .0001), but was bilaterally symmetric in mSOP. Mean preoperative central gaze hypertropia was similar at 14.7±9.8Δ in SOP and 11.0±6.9Δ in mSOP (P = .2). The commonest surgery was ipsilateral inferior oblique (IO) weakening combined with contralateral inferior rectus (IR) recession, followed by ipsilateral IO weakening alone and contralateral IR recession alone. After 41±65 months' follow-up in SOP and 22±41 months in mSOP, central gaze hypertropia decreased from 14.7±9.8Δ to 1.7±4.1Δ in SOP, and from 11.0±6.9Δ to -2.9±5.4Δ in mSOP (both P < .0001). Surgical effect was similar at 13.2±10.3Δ in SOP and 14.1±10.0Δ in mSOP. Reoperation rate was low and similar in both groups.
Conclusion:
Clinical characteristics and surgical effect are similar in mSOP and SOP. Conventional surgeries are comparably effective in both. This suggests that mechanism beyond SO muscle function drive head tilt-dependent cylcovertical strabismus.
