Clinical Pearls and Management Recommendations for Strabismus due to Thyroid Orbitopathy

The role of lateral rectus muscle resection for severe esotropia after medial rectus muscle myectomy in Graves' ophthalmopathy

PURPOSE

Persistent diplopia after rectus muscle myectomy is not uncommon but challenging in patients with Graves' ophthalmopathy. We investigated the role of lateral rectus muscle resection for patients after medial rectus muscle myectomy in Graves' ophthalmopathy.

METHODS

We retrospectively reviewed and collected data from patients with persistent diplopia after medial rectus muscle myectomy for Graves' ophthalmopathy who underwent unilateral or bilateral lateral rectus muscle resection. The eyeball deviations in the primary and reading positions before and after the operation were measured. A successful surgical outcome was defined as having less than five prism diopters (PD) in the primary gaze and functional binocular vision in the central 30° field postoperatively.

RESULTS

A total of fifteen patients were included (mean post-myectomy deviation: 35.9 PD, range: 14 to -75 PD). The lateral rectus muscle resection after medial rectus muscle myectomy achieved an 80.0% success rate, with one patient over-corrected and two patients under-corrected.

CONCLUSIONS

The lateral rectus muscle resection is an effective and predictable procedure for managing residual esotropia in Graves' ophthalmopathy patients who have previously undergone medial rectus muscle myectomy.

Treatment of Graves' ophthalmopathy

Graves' ophthalmopathy is an inflammatory disease with primary involvement of the extraocular muscles and the orbit. It encompasses the most common extra-thyroid manifestation in patients with Graves-Basedow disease. The underlying cause is molecular mimicry with the TSH receptor in ocular fibroblasts, leading to an immuno-mediated pathogenesis. Glucocorticoids at high doses are the cornerstone in moderate-severe cases. However, some patients are corticorresistant or intolerant. In recent years, therapeutic novelties have been described in terms of the dosage of the immunosuppressive treatments used, as well as the emergence of biological therapy in this field. The objective of this review is to update the treatment of Graves' ophthalmopathy, as well as to present alternative options in patients resistant or intolerant to glucocorticoids.

Management of Thyroid Eye Disease-Related Strabismus

Purpose:

To review various treatment methods in thyroid eye disease (TED) related strabismus.

Methods:

We searched in PubMed and Google Scholar and Ovid MEDLINE for keywords including TED-related strabismus, strabismus in thyroid-associated ophthalmopathy, Graves^' ophthalmopathy related strabismus or squint, and restrictive strabismus. Two expert strabismus specialists selected and evaluated the English articles that were related to our paper and had been published since 2000. Some articles were added based upon the references of the initial articles.

Results:

One hundred fifteen articles were found, 98 of which were mostly related to the topic of this review. Management of TED-related strabismus was reviewed and categorized in non-surgical and surgical. Botulinum toxin A (BTA) is a useful non-surgical management of strabismus in an active TED and residual deviation after strabismus surgery. Postoperative under-correction is relatively more common in TED-related esotropia. Lateral rectus resection and BTA are the options to manage the problem. Muscle rectus muscle resection should be performed after maximum recession of restricted muscles. It should be avoided on a restricted or enlarged muscle. Management of TED-related vertical deviation is challenging. In these cases, the surgical treatment selected depends on forced duction test (FDT) (pre and intraoperative), orbital imaging (which muscle is enlarged), and the amount of vertical deviation (in both down-gaze and primary position).

Conclusions:

TED-related strabismus needs careful evaluation and management to achieve optimal outcome. Different surgical and non-surgical options are available for intervention in TED-related strabismus.

Prioritising downgaze alignment in the management of vertical strabismus for thyroid eye disease: principles and outcomes

OBJECTIVE

To evaluate outcomes of surgery for vertical strabismus in thyroid eye disease (TED) employing a set of surgical principles aimed at avoiding reversal of downgaze deviation while restoring binocular single vision (BSV).

METHODS

A retrospective review of consecutive patients undergoing vertical strabismus surgery for TED using a set of surgical principles between 2008 and 2017. Principle outcome measure was the presence of BSV in primary position and downgaze 3 months postoperatively and at latest follow-up.

RESULTS

Thirty five patients (29% male) with a mean age of 58 years (range 31-83 years) were included. Median follow-up was 16 months. At presentation, 17 (49%) used monocular occlusion to avoid diplopia; the remainder used a prism and/or abnormal head posture. In 12 (34%), combined horizontal and vertical muscle surgery was required. Median (inter-quartile range) preoperative vertical deviations in primary position and downgaze respectively were 20 prism dioptres (Δ) (15, 30) and 18Δ (8, 22), which improved to 1Δ (0, 3) and 1Δ (0, 3) after the first operation. BSV in primary position and downgaze, without prism, after a single surgery was achieved in 29 (83%). Second surgery was required in 5 (14%) and one patient who had reactivation of her TED required a third surgery. At final follow-up (median 16 months), 32 (91%) were diplopia free without prisms; 3 (9%) used a small prism correction (range 2-12Δ); no patients were left with intractable diplopia.

CONCLUSIONS

Our management principles are characterised by prioritising downgaze alignment to avoid downgaze diplopia reversal, whilst limiting adjustable sutures and employing standard surgical dosing. They give favourable outcomes in TED associated vertical strabismus.

Effectiveness of Bilateral Lateral Rectus Resection for Residual Esotropia in Dysthyroid Ophthalmopathy

PURPOSE

To report one surgeon's experiences with bilateral lateral rectus resections in dysthyroid ophthalmopathy patients with residual esotropia after initial bilateral medial rectus recession.

DESIGN

Retrospective interventional case series evaluating outcomes.

METHODS

Medical records for patients with dysthyroid ophthalmopathy who underwent bilateral lateral rectus resections for persistent esotropia by a single surgeon from June 2012 to June 2015 were retrospectively reviewed. All patients had residual esodeviations following initial bilateral medial rectus recession. The goal of surgery was to obtain fusion in primary gaze and the reading position without prism, with a postoperative deviation equal to or less than 8^Δ at distance and a phoria at near without diplopia.

RESULTS

Seven of the 9 patients were successful in achieving this goal. Preoperative esotropia before resection ranged from 12^Δ to 30^Δ (23.1^Δ ± 10.3^Δ) at distance and -2^Δ to 40^Δ (14.9^Δ ± 12.3^Δ) at near. No exodeviation was created at near by the resections, but 1 patient had an asymptomatic exophoria both pre- and postoperatively.

CONCLUSION

Patients with large horizontal misalignment may have residual esodeviations that are too large for correction with recession alone. Given our findings, we believe resection may be an effective tool in resolving esotropia in certain patients with restrictive strabismus.