Transient internal ophthalmoplegia with anisocoria and loss of accommodation after inferior oblique recession in a 5-year-old

Inferior oblique recession is a widely used operation for the treatment of strabismus. This surgical procedure has been practiced for many years and generally has not had serious complications. Here, we describe a case of transient internal ophthalmoplegia causing pupillary dilatation and loss of accommodation after inferior oblique recession. Internal ophthalmoplegia has been previously reported as a complication of procedures in which significant manipulation of the inferior oblique occurred, such as denervation and extirpation, myectomy, recession, repair of orbital floor fractures, and sinus surgery.1Bajart A.M. Robb R.M. Internal ophthalmoplegia following inferior oblique myectomy: a report of three cases.Ophthalmology. 1979; 86: 1401-1404Abstract Full Text PDF PubMed Scopus (7) Google Scholar, 2Bladen J.C. Moosajee M. Angunawela R. Roberts C. Transient internal ophthalmoplegia after inferior oblique myectomy.J AAPOS. 2009; 13: 596-597Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar, 3Kim W.J. Kim M.M. Permanent tonic pupil following inferior oblique myectomy.J AAPOS. 2015; 19: 193-194Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar, 4Bayramlar H. Miman M. Demirel S. Inferior oblique paresis, mydriasis, and accommodative palsy as temporary complications of sinus surgery.J Neuroophthalmol. 2004; 24: 225-227Crossref PubMed Scopus (19) Google Scholar, 5Biedner B. Ebner R. Yassur Y. Internal ophthalmoplegia following inferior oblique muscle recession.J Neuroophthalmol. 1987; 7: 249-250Crossref Scopus (1) Google Scholar A proposed mechanism is traction on the inferior oblique and neurofibrovascular bundle, with subsequent trauma to the ciliary ganglion.1Bajart A.M. Robb R.M. Internal ophthalmoplegia following inferior oblique myectomy: a report of three cases.Ophthalmology. 1979; 86: 1401-1404Abstract Full Text PDF PubMed Scopus (7) Google Scholar We propose that the same mechanism of injury occurred in our patient, despite the use of a less aggressive inferior oblique weakening procedure. We report a rare surgical complication in a 5.5-year-old girl with a history of intermittent exotropia, which was first noticed by her parents at the age of 6 months. She had been followed by pediatric ophthalmology since 1.5 years of age. During that time, she was treated for strabismic amblyopia in her left eye intermittently between 1.5 and 3.5 years of age. The size of her intermittent exotropia on cover testing increased over the years. At the age of 5.5 years, she revealed a primary deviation while fixating with her right eye, of a left intermittent exotropia with poor control, measuring 16 prism diopters at distance. Interestingly, she demonstrated a secondary deviation when fixating with her amblyopic left eye of a right esotropia of 8 prism diopters. Versions demonstrated asymmetric elevation in adduction, 1+ in the right eye and 3+ in the left eye. Visual acuity measured 20/20 in her fixating right eye, and 20/30 in her nonfixating left eye. A cycloplegic refraction 4 months ago showed right eye +1.50 +0.50 × 130, left eye +2.50 +0.50 × 70. Her parents noted significant psychosocial concerns from her strabismus and chose to proceed with strabismus surgery. At 5.5 years of age, she underwent left lateral rectus recession of 6.5 mm and bilateral asymmetric recession of the inferior obliques, left more than right. In relation to the lateral border of the insertion of the inferior rectus muscle, the right inferior oblique was placed 4 mm posterior and 2 mm lateral, whereas the left inferior oblique was placed 3 mm posterior and 1 mm lateral. The techniques for recession of the inferior obliques were otherwise unchanged. A Gass hook was used to tie a 4-0 silk traction suture around the lateral rectus. The inferior oblique muscle was isolated using small and medium hooks. Once dissected from its fascial attachments, a small straight hemostat was used to clamp the muscle near its insertion. Wescott scissors were used to disinsert the muscle. A 6-0 double-arm Vicryl suture was used to imbricate the muscle with 1 central pass and 2 full-thickness locking bites on either end. The hemostat was then released, and scleral passes were made at the previously described locations. In all, the surgery was uneventful and no intraocular complications were noted. On postoperative day 2, the patient's right pupil was fixed and dilated. She fixated with her amblyopic left eye, demonstrating a right esotropia of 20 prism diopters. By postoperative day 10, her right pupil remained nonreactive to light and measured 7 mm. Without correction, her vision in the right eye was 20/60 at distance and 20/400 at near, which improved to 20/30 at distance with +1.50 +0.50 × 110 and 20/20 at near with +4.50 sphere. She continued to fixate with her amblyopic left eye, demonstrating a right esotropia of 20 prism diopters. We had a strong suspicion for damage to her right ciliary ganglion from intraoperative traction on her right inferior oblique. She was treated with a 3-week course of tapering oral prednisolone, and pilocarpine 1% right eye as needed for dilation and blurriness. On postoperative day 30, her accommodation improved. Her measured acuity was 20/30+ at distance and 20/25 at near without correction in her affected right eye. She also resumed her preoperative fixation preference for her right eye. Cover test revealed a left intermittent exotropia of 8 prism diopters. Her right pupil remained 7 mm and nonreactive. By 4 months postoperatively, she began to regain some pupillary function, and by 9 months postoperatively, there was no residual anisocoria. Her alignment at that visit was orthophoric at distance with mild bilateral elevation in adduction. Her parents did not note any ocular misalignment or pupillary asymmetry. Internal ophthalmoplegia is a rare complication that has been described with a variety of inferior oblique weakening procedures. Most reported instances of internal ophthalmoplegia were temporary, with a near-complete recovery of the pupillary function within 3–6 months after surgery.2Bladen J.C. Moosajee M. Angunawela R. Roberts C. Transient internal ophthalmoplegia after inferior oblique myectomy.J AAPOS. 2009; 13: 596-597Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar In severe cases though, permanent tonic pupil after inferior oblique weakening has been described, including after recession.1Bajart A.M. Robb R.M. Internal ophthalmoplegia following inferior oblique myectomy: a report of three cases.Ophthalmology. 1979; 86: 1401-1404Abstract Full Text PDF PubMed Scopus (7) Google Scholar,3Kim W.J. Kim M.M. Permanent tonic pupil following inferior oblique myectomy.J AAPOS. 2015; 19: 193-194Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar,5Biedner B. Ebner R. Yassur Y. Internal ophthalmoplegia following inferior oblique muscle recession.J Neuroophthalmol. 1987; 7: 249-250Crossref Scopus (1) Google Scholar The proposed mechanism is traction on the neurovascular bundle of the inferior oblique and subsequent stretching of the ciliary ganglion, which provides parasympathetic innervation for pupillary constriction and accommodation. It is plausible that procedures that place greater traction to the neurovascular bundle, such as myectomy or denervation and extirpation, may be at higher risks of this complication. There is no clear treatment to improve the long-term recovery of the condition. Some authors have advocated for the use of 1% pilocarpine to reduce anisocoria and blurred vision while awaiting resolution.2Bladen J.C. Moosajee M. Angunawela R. Roberts C. Transient internal ophthalmoplegia after inferior oblique myectomy.J AAPOS. 2009; 13: 596-597Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar Treatment with oral steroids had been described in one previous case of internal ophthalmoplegia after sinus surgery.4Bayramlar H. Miman M. Demirel S. Inferior oblique paresis, mydriasis, and accommodative palsy as temporary complications of sinus surgery.J Neuroophthalmol. 2004; 24: 225-227Crossref PubMed Scopus (19) Google Scholar Although our patient received a 3-week tapering course of oral prednisolone, we lack sufficient data to determine if steroids contributed to her recovery. Our patient's accommodation recovered sooner than her pupillary function. In summary, our case demonstrates that internal ophthalmoplegia is a possible complication of inferior oblique recession. We recommend minimizing traction on the inferior oblique as much as possible during surgery. If a muscle clamp or hemostat is used on the inferior oblique, care should be given to reduce traction and release the clamp as soon as feasible. The authors have no proprietary or commercial interest in any materials discussed in this article.