Dissociated vertical deviation is the tendency for an eye to elevate, abduct, and extort when binocularity is disrupted. Most consider superior rectus recession as the treatment of choice for pure dissociated vertical deviation without inferior oblique overaction.1 If dissociated vertical deviation and inferior oblique overaction coexist, J deformity anteriorization of the inferior oblique muscle is chosen because this will address both issues.2–4 Previous authors have successfully treated dissociated vertical deviation with inferior oblique anteriorization, even in the absence of inferior oblique overaction.5
A 5-year-old boy presented to the Pediatric Ophthalmology Department of the Children's Hospital of Cairo University in 2015. The patient's mother complained of the boy's ocular deviation since birth. Additionally, the mother mentioned complaints suggestive of a visual field defect. Juvenile glaucoma was diagnosed due to an intraocular pressure (IOP) of 24 and 28 mm Hg (Perkins hand-held applanation tonometer; Haag-Streit UK, Essex, United Kingdom) and cup–disc ratios of 0.2 and 0.4 in the right and left eyes, respectively, as well as advanced field defects on perimetry, despite bilateral clear corneas with diameters of 11.5 mm. Central corneal thickness was 611 and 602 microns in the right and left eyes, respectively.
Corrected visual acuity was 0.2 and 0.4 in the right and left eyes, respectively. Cycloplegic refraction was +2.00 +2.00 × 100 and +2.5 +1.5 × 60 in the right and left eyes, respectively. Extraocular muscle examination revealed bilateral dissociated vertical deviation that measured 20 and 30 prism diopters (PD) in the right and left eyes, respectively, and an intermittent exotropia of 60 PD with equal fixation preference, A-pattern deviation, and bilateral +2 superior oblique overaction. Additionally, there was bilateral mild ptosis and compensatory chin depression (Figure 1).
Preoperative composite showing exotropia, dissociated vertical deviation with normally acting inferior oblique muscles, A-pattern deviation, and bilateral superior oblique overaction.
Dorzolamide hydrochloride–timolol maleate was initially prescribed, which lowered the IOP to 20 and 16 mm Hg in the right and left eyes, respectively. However, surgical treatment was recommended due to the patient already having symptomatic field defects and the impracticability of continuing medical antiglaucoma treatment in a child.
Subscleral trabeculectomies were performed bilaterally to treat glaucoma, with an Ologen implant (Aeon Astron Europe B.V., Leiden, The Netherlands) in the left eye 2 weeks after presentation and mitomycin C in the right eye 2 months later. Five months after normalization of IOP (18 and 16 mm Hg in the right and left eyes, respectively), strabismus surgery was performed. This was in the form of bilateral 10-mm recessions of the lateral rectus muscles and “J” deformity anteriorization of the inferior oblique muscles,4 where the anterior and posterior poles of the inferior oblique muscles were sutured 1 mm apart and level with the inferior rectus insertion. No complications resulted from any of the surgeries except for a small pigmented cyst at the trabeculectomy site in the left eye. Follow-up of the patient was performed 1 day, 1 week, and monthly after each operation. At each visit, the IOP, optic discs, blebs, anterior segments, and extraocular muscles were evaluated.
Ten months following strabismus corrective surgery, the dissociated vertical deviation reduced to 16 and 5 PD in the right and left eyes, respectively. There was horizontal orthotropia at distance but an exotropia of 16 PD at near in the primary position and down gaze and an exotropia of 30 PD in up gaze (Y-pattern), with persistence of superior oblique overaction and ptosis (Figure 2). Refraction remained essentially the same.
Postoperative composite showing intermittent exotropia, Y-pattern deviation, and bilateral superior oblique overaction. Dissociated vertical deviation is not seen due to its intermittence.
Strabismus reoperation was performed immediately after the 10-month postoperative follow-up visit. A missed segment of the right inferior oblique muscle was found not anteriorized. This segment was myectomized. Additionally, the right lateral rectus muscle was found 14 mm posterior to the limbus and was recessed 3 mm further. Muscle scleral plication of both inferior rectus muscles was performed (5 and 3 mm in the right and left eyes, respectively).
Six weeks following reoperation, the patient had orthotropia at distance and near, in both primary position and down gaze, and a 14-PD exotropia in up gaze. There was persistence of +1 superior oblique overaction bilaterally. There was no remarkable change in the palpebral fissure width. IOP was 14 and 18 mm Hg in the right and left eyes, respectively. Optical coherence tomographic analysis of the optic nerve, ganglion cell layer, and retinal nerve fiber layer revealed below normal values of the retinal nerve fiber and ganglion cell layer thicknesses in all quadrants.
The classic treatment option for dissociated vertical deviation without an inferior oblique over-action is recession of the superior rectus muscle.1 This treatment option would have had two advantages with this patient: improvement of ptosis by producing upper eyelid retraction6 and reduction of A-pattern deviation. However, the treatment carried a risk of compromising the child's functioning blebs and producing fibrosis in the superior subconjunctival space, thus compromising a second subscleral trabeculectomy if subsequently needed. Even superior rectus muscle bridle sutures were reported to compromise success rates of filtering blebs.7 Therefore, the author decided against superior rectus or oblique surgery, giving priority to the success of a surgical treatment for glaucoma, which is a potentially blinding disease.
A second reported treatment option for the correction of dissociated vertical deviation is a bilateral inferior rectus tuck.8 This would reduce the associated A-pattern deviation without compromising the superior subconjunctival space, but carries a risk of further narrowing of the palpebral fissure. Therefore, this option was initially avoided.
The third treatment option for dissociated vertical deviation is J deformity anteriorization of the inferior oblique muscles.3–5,9 This would conserve the superior subconjunctival space without producing eyelid fissure changes. This treatment option was previously proven effective to correct dissociated vertical deviation with and without inferior oblique overaction.5 Accordingly, this treatment option was chosen in this case.
Worsening of A-pattern deviation was feared after J deformity anteriorization of the inferior oblique muscle; on the contrary, it was reversed into a Y-pattern. Kushner2 reported a Y- or V-pattern deviation following bilateral inferior oblique anteriorization and considered it to be part of an “anti-elevation syndrome.” A substantial persistent extorsion was the proposed mechanism for this pattern. The patient described here developed a Y-pattern deviation, but there was no macular torsion or any other manifestations of anti-elevation syndrome. A different proposed explanation for the development of Y-pattern deviation in this case is the reversal of both the abducting and elevating actions of inferior oblique muscles after their placement in front of the equator, thus becoming a depressor and adductor and producing a Y-pattern deviation.
Regarding strabismus reoperation, the author opted for inferior rectus plication and against superior rectus recession to spare the superior fornix. This gave priority to the success of filtering blebs over the risks of palpebral fissure narrowing.
The decision-making process in this complex case of surgically treated glaucoma and complex vertical strabismus was mainly driven by the desire to avoid compromising the functioning blebs, spare the superior fornix in the event that further glaucoma surgeries were needed, and avoid further narrowing an already small fissure of a ptotic eyelid. Superior rectus recession was absolutely avoided for the sake of the functioning blebs and inferior rectus surgery was avoided to circumvent eyelid fissure changes. J deformity anteriorization of the inferior oblique muscle was the best treatment option in this case of dissociated vertical deviation, even in the absence of inferior oblique overaction. Inferior rectus surgery was initially avoided, but was necessary on a subsequent reoperation; however, it did not cause eyelid fissure changes.
Two messages are conveyed through this case report. First is the importance of history-taking, where symptoms of visual field defects drew the attention of the author to the presence of glaucoma, which was initially missed by other ophthalmologists despite being given the same history. Second is that J deformity anteriorization of the inferior oblique muscle corrects both dissociated vertical deviation and A-pattern deviation because anteriorization reverses both its vertical and horizontal actions, turning the muscle into a depressor and adductor.
- Wright KW, Strube YNJ. Complex strabismus: dissociated strabismus complex (DVD and DHD). In: Wright KW, Strube YNJ, eds. Color Atlas of Strabismus Surgery: Strategies and Techniques. 4th ed. New York: Springer; 2015:44–45.
- Kushner BJ. Restriction of elevation in abduction after inferior oblique anteriorization. J AAPOS. 1997;1:55–62. doi:10.1016/S1091-8531(97)90024-0 [CrossRef]
- Black BC. Results of anterior transposition of the inferior oblique muscle in incomitant dissociated vertical deviation. JAAPOS. 1997;1:83–87.
- Wright KW, Strube YNJ. Inferior oblique muscle weakening procedures. In: Wright KW, Strube YNJ, eds. Color Atlas of Strabismus Surgery: Strategies and Techniques. 4th ed. New York: Springer; 2015:135–146. doi:10.1007/978-1-4939-1480-7_17 [CrossRef]
- Nabie R, Anvari F, Azadeh M, Ameri A, Jafari AK. Evaluation of the effectiveness of anterior transposition of the inferior oblique muscle in dissociated vertical deviation with or without inferior oblique overaction. J Pediatr Ophthalmol Strabismus. 2007;44:158–162.
- Wright KW, Strube YNJ. Rectus muscle recession: vertical rectus muscle recession. In: Wright KW, Strube YNJ, eds. Color Atlas of Strabismus Surgery: Strategies and Techniques. 4th ed. NY: Springer; 2015:90–102.
- Li B, Zhang M, Liu W, Wang J. Comparison of superior rectus and peripheral lamellar corneal traction suture during trabeculectomy. Curr Eye Res. 2016;41:215–221. doi:10.3109/02713683.2015.1009635 [CrossRef]
- Diab MMK. Inferior rectus tucking versus combined superior rectus recession with posterior fixation suture (faden) for the treatment of dissociated vertical deviation without inferior oblique overaction. Journal of the Egyptian Ophthalmological Society. 2013;106:239–244. doi:10.4103/2090-0686.131573 [CrossRef]
- Engman JH, Egbert JE, Summers CG, Young TL. Efficacy of inferior oblique anterior transposition placement grading for dissociated vertical deviation. Ophthalmology. 2001;108:2045–2050. doi:10.1016/S0161-6420(01)00801-6 [CrossRef]