Torsional Diplopia

A simple marking system for accurate intraoperative monitoring and adjustment of cyclotorsion strabismus surgery

Ocular cyclotorsion is treatable only with surgery. The surgical procedure must be tailored individually to the specific etiologies causing the horizontal and vertical strabismus and its torsional components. An adjustable surgical approach is often used for postoperative or intraoperative adjustments. However, the methods currently used have some limitations. In this study, we propose a simple intraoperative marking system for all cyclotorsion correction surgery. The proposed marking system used three sets of surface markers: external horizontal markings, ocular horizontal markings, and surgical torsion markings, drawn in sequence. We retrospectively analyzed the surgical results using this novel marking system in this single-center, single-surgeon study. Fifteen patients with cyclotorsion who underwent treatment using the proposed marking system as an intraoperative aid between August 2019 and August 2021 were included. The medical charts were thoroughly reviewed, and the pre-and postoperative subjective and objective cyclotorsion were analyzed. Among the study subjects (10 males, 5 females; age range: 6-89 years), 13 had excyclotorsion and 2 incyclotorsion. Preoperative mean net subjective cyclotorsion measured by the double Maddox rod (DMR) test was 6.0° (standard deviation: 10.8°) and mean net disc-to-fovea angle (DFA) was 20.23° (13.21°). The postoperative net DMR and DFA were 0.2° (2.1°) and 14.09° (5.97°), respectively. The mean absolute net DMR and DFA being treated were 9.8° (4.8°) and 9.76° (4.61°). Overall, the proposed intraoperative marking system is a simple and quantitative method to assess, monitor, and adjust the torsional aspect for all strabismus surgeries.

Surgical outcome of graded Harada-Ito procedure in the treatment of torsional diplopia ‒ a retrospective case study with long-term results

To review and evaluate the surgical outcomes of the Fells-modified Harada-Ito procedure using a dosage scale approach with long-term follow up in patients with torsional diplopia. The records of patients who underwent the modified Harada-Ito procedure by the same surgeon during 2012-2019 were retrospectively reviewed regarding pre- and post-operative data and individual dose-scale used for the surgery. The modified Harada-Ito procedure involved advancing the anterior half of the superior oblique tendon toward the inferior edge of the lateral rectus muscle by a distance determined using a five-graded scale. A total of 27 patients (mean age 57.6 years, range, 22-81 years; 10 female) were included. Evaluating surgical outcome showed a significant difference in pre- to post-operative cyclodeviation (p = <0.001). Pre-operative mean extorsion was -10.4° and mean torsional correction achieved was 7.7°. The dose-effect relationship showed a wide spread effect, yet yielded a high success rate. All but two patients were symptom free from their torsional diplopia at the last post-operative evaluation, on average 24 months after surgery. Post-operative results and the dose-effect of the modified Harada-Ito corresponded with the aimed-for correction of torsional diplopia.. Fusion evaluation and individually based pre-operative assessments proved essential in determining individual doses for successful surgical outcomes.

Clinical measurements of normative subjective cyclotorsion and cyclofusion in a healthy adult population

PURPOSE

To investigate normative subjective cyclotorsion values and cyclofusion ranges in a healthy adult population.

METHODS

A cross-sectional investigation was performed in 120 healthy, non-strabismic adults, 60 men and 60 women in the age range of 18-69 years. All subjects were assessed for cyclotorsion using the synoptophore and the single Maddox rod (SMR) methods. Cyclofusion was investigated with the synoptophore in 60 of the subjects.

RESULTS

All age groups showed low values of subjective torsion, mainly excyclotorsion with mean values of -1 degree for both methods. Reference ranges of cyclotorsion were between -0.7 and -1.5 degrees for the SMR method and between -0.7 and -1.4 degrees using the synoptophore method. There were no significant differences between gender (p = 0.48), but the effect of age was significant for both methods (p = 0.026) demonstrating a slight increase in excyclotorsion with age. Cyclofusion showed a total mean amplitude of 16 degrees, the fusion range was +7 degrees of incyclotorsion to -9 degrees of excyclotorsion.

CONCLUSIONS

Subjective reference ranges for cyclotorsion and cyclofusion reveal that low values of torsion are to be expected upon clinical investigation in non-strabismic adult individuals. Values outside of the reference range may be indicators of possible binocular abnormalities or physiological variations. The cyclotorsional measurements and prevalence in this adult population group can be regarded as normative data in clinical settings.

A novel test for predicting fusional potential in patients with torsional diplopia

We introduce the novel "white disk" test to evaluate fusional potential in patients with torsional diplopia. In this test, a white disk is presented on a black background in a darkened room to eliminate perception of torsion. Horizontal and vertical misalignment is neutralized with prisms when necessary. The absence of diplopia on the white disk test is used to establish fusional ability. Nine patients with torsional diplopia were assessed using this test. All had excyclotorsion (mean, 9.9° ± 4.2°; range, 5°-15°) and could achieve single binocular vision on testing. Postoperatively, 9 patients reported no torsional diplopia in the preferred gaze position, with a mean excyclotorsion of 0.4° ± 2.8° (range, -5° to 4°). The test appeared to predict fusional potential in all patients.

Inadvertent inferior oblique extirpation during orbital decompression

PURPOSE

To report a case of inadvertent inferior oblique extirpation during orbital decompression, its management, and postoperative result.

METHODS

A 38-year-old female with thyroid eye disease underwent cosmetic right orbital decompression during whichinferior oblique extirpation was noticed.

RESULT

The muscle was repaired on the same session (illustrated in the article) with no postoperative diplopia at 3-month follow-up.

CONCLUSION

Inferior oblique injury should be considered among the uncommon yet important complications of orbital decompression. It can be easily found and repaired in the same session as demonstrated in this case report.