20 However, results for pattern XT and with Duane syndrome-related upshoot were variable. : Slipped muscle; following tenotomy or tenectomy procedures), Trauma (The IV cranial nerves exit the midbrain very closely so that strong head traumas, or sometimes even small ones, frequently origin bilateral rather than unilateral palsies), Iatrogenic (ex. The terminology regarding Brown syndrome has varied and was often confusing. Duane1 introduced the concept of pattern in strabismus in 1897 when he described V pattern in bilateral superior oblique palsy. This page was last edited on April 19, 2023, at 13:28. American Academy of Ophthalmology. Careers. The diagnosis of Brown Syndrome is based on the clinical findings and history. [43], In inferior oblique overaction there is an increase of ipsilateral hypertropia in adduction to the contralateral side with a contralateral hypotropia, whereas in DVD, there is a hypertropia in adduction as well as in and abduction without a true contralateral hypotropia, when binocular fusion is interrupted. Furthermore, careful history including associated symptoms and other past medical history can help distinguish a CN 4 palsy from other items on the differential. Brown HW. It frequently coexists with an underaction of the contralateral IR and intermittent exotropia. A and V patterns seen in exodeviation and esodeviation. a #240 retinal silicone band), a non-absorbable "Chicken suture", or a superior oblique split tendon lengthening procedure, Iatrogenic Brown syndrome secondary to muscle plication may require reversal of the plication, In case the primary cause is a tendon cyst, removal of the cyst may be indicated. Most frequently idiopathic or iatrogenic (following inferior oblique surgery or retrobulbar block). Boyd TA, Leitch GT, Budd GE. 2013. doi:10.1212/WNL.0b013e3182a031ea, Wong AMF, Colpa L, Chandrakumar M. Ability of an upright-supine test to differentiate skew deviation from other vertical strabismus causes. Piotr Loba Monocular Elevation Deficit Syndrome (MEDS), Other complex forms of strabismus or involving multiple muscles, Differentiating between a Paresis and a Restriction of the Antagonist, Three Step Test for Cyclovertical Muscle Palsy, Differentiating between Browns Syndrome, Superior Oblique Overaction and Inferior Oblique Paresis, Differential Diagnosis between DVD and Inferior Oblique Overaction, Vertical Strabismus Exam Findings by Etiology, Pseudo - Inferior Rectus Underaction (as in orbital floor fracture and muscle entrapment). Is not perceived by the patient, but rather by the observer. If congenital: There is an indication for surgery if there is a vertical deviation in primary position with an important face turn. Vertically incomitant pattern strabismus is used to describe the type of strabismus wherein the amount of horizontal deviation changes during the excursion of the eye from upgaze to downgaze. Vertical misalignments of the eyes typically results from dysfunction of the vertical recti muscles (inferior and superior rectus) or of the oblique muscles (the inferior oblique and superior oblique). In the presence of a significant Y pattern in upgaze, even if there is no significant deviation in primary position or sidegaze: Bilateral IO weakening procedures. 2008;126(7):899-905. doi:10.1001/archopht.126.7.899, Lee J, Flynn JT. However, oblique muscles have the greatest effect on vertical alignment when the eye is adducted and so are tested in adduction. Note convergence in straight upgaze, an important point of differentiation from Brown syndrome. Tip: You can draw the cardinal positions of gaze as above and circle: 1) the bottom muscles on the higher eye and top muscles on the lower eye, 2) the muscles to the patient's right in both eyes if worse in right gaze or to the patient's left in both eyes if worse in left gaze, 3) the muscles in line with whichever direction the head tilt is worse. A spontaneous resolution of congenital Browns syndrome has been reported. Cooper C,Kirwan JR,McGill NW,Dieppe PA. Brown's syndrome: an unusual ocular complication of rheumatoid arthritis. Amblyopia is generally absent. Other less commonly performed procedures are: Occurrence of a pattern in horizontal comitant strabismus is an interesting phenomenon. 2010;30(1):59-63. doi:10.1097/WNO.0b013e3181ce1b1d, Prasad S, Volpe NJ. (Courtesy of Vinay Gupta, BSc Optometry), Figure 6. Abnormalities of the fascial anatomy is considered to be a rare cause. Surv Ophthalmol. Other features: Intorsion and abduction in downgaze. adalimumab) have been used in refractory cases. Thyroid eye disease leads to enlargement of the extraocular muscles and restrictive strabismus. Passing through the trochlea it changes direction, passes deep to the superior rectus muscle, and inserts into the superior . The nucleus gives rise to the IV nerve fascicle which decussates at the level of the anterior medullary velum (the roof of the aqueduct) just caudal to the inferior colliculus. Duane A. Brown H. Isolated Inferior Oblique Paralysis: An Analysis of 97 Cases. Differentiation between IO palsy and SO restriction of Browns can be done using Forced Duction Test. Department of Ophthalmology and Visual Sciences, University of Wisconsin-Madison, Madison, Wisconsin, USA, You can also search for this author in Miller MM, Guyton DL. Cause: Any cause leading to a disruption of normal binocular development can be at its origin. [4], Trauma -, Lee J. Sagittalization of the oblique muscles as a possible cause for the A, V, and X phenomena. The identification of the pattern and its underlying mechanism is essential to plan a proper surgical management in strabismus. If the degree of deviation in all fields of gaze, it is classified as comitant; it if behaves differently in different fields of gaze, it is classified as incomitant. Knapp P. Vertically incomitant horizontal strabismus, the so called A and V syndromes. Limited elevation in straight-up gaze and abduction can also be present, but are more subtle. X- pattern, It is caused by a tight, contracted lateral rectus. A preliminary report. It can be acquired or congenital and is caused by damage to the trochlea of the superior oblique muscle tendon, an abnormality of the superior oblique tendon itself, abnormalities of the tissue around the rectus extraocular muscles (the rectus pulleys), or a congenital abnormality of the superior oblique muscle itself. Magnetic resonance imaging of the head (MRI) is often unremarkable in CNV IV palsy but may show a dorsal midbrain contusion or hemorrhage.[5]. Simultaneous superior oblique tenotomy and inferior oblique recession in Brown's syndrome. When bilateral, the vertical deviation of each eye is not related to the other, as in true hypertropia (no yoke muscle overaction is present).[4][41]. If the patient has binocular fusion, weakening the superior oblique may give rise to extorsional diplopia. Depending on which eye is fixing, a hypertropia of one eye is the same as a hypotropia of the fellow eye. PMID 32088116. Additionally, the fourth cranial nerve exits dorsally, crosses the midline, and innervates the contralateral SOM. This hypothesis has gained support from the confluence of evidence from a number of independent studies. BMC Ophthalmol. CrossRef The SOM has action that varies depending on the angle between the muscle plane and the visual axis. : Craniosynostosis; extorted orbit), Iatrogenic (ex. There are eight possible muscles that could cause a hypertropia -- the bilateral superior recti, inferior recti, superior obliques and inferior obliques. Following ocular surgery (Ex. Provided by the Springer Nature SharedIt content-sharing initiative, Over 10 million scientific documents at your fingertips, Not logged in Part of Springer Nature. Skew deviation may demonstrate decreasing vertical strabismus with position change from upright to supine. Elliott RL, Nankin SJ. Figure 5. The tree-step-test is not diagnostic when more than one muscle is affected or there is a restrictive cause; there are some situations where a false positive result can lead to a misdiagnosis: A paresis of more than one vertical muscle, contracture of the vertical recti, previous vertical muscle surgery, skew deviation, myasthenia gravis, dissociated vertical deviation and small vertical deviations associated with horizontal strabismus. The .gov means its official. Free tenotomy, tenectomy, Z-tenotomy and split-lengthening procedures have also been described. It is frequently traumatic. It frequently leads to a contralateral hypertropia due to overaction of the yoke muscle (SR). a. Additional fourth step to distinguish from skew deviation. It progresses through the lateral wall of the cavernous sinus. Myectomy and extirpation/denervation have been described but are not preferred procedures by the authors, as the results may be unpredictable, and anteriorization cannot be achieved by these procedures. In severe cases, there may be both a hypotropia in primary position and downshoot in adduction. Sometimes it can give rise to an acquired Browns syndrome, due to SO contracture (for the differential diagnosis between SO overaction and Browns syndrome, see the differential diagnosis section). By convention, the misalignment is typically labelled by the higher, or hypertropic, eye. High myopia, where a posterior staphyloma misplaces the lateral rectus inferiorly. Pusateri TJ, Sedwick LA, Margo CE. In adduction, the superior oblique is primarily a depressor. A next step in naming and classification of eye movement disorders and strabismus. J AAPOS. MeSH Strabismus. (Courtesy of Vinay Gupta, BSc Optometry). Several patterns have been described for the type of vertical incomitance observed (eg, A or V patterns), depending upon the relative increase or decrease in the horizontal deviation during the vertical eye movement. 2015;19:e14. Alternating hypertropia on horizontal gaze or tilt, Positive Bielschowsky head tilt test to either shoulder, Large degree of excyclotorsion (> 10 degrees), Absent or small hypertropia in primary gaze, Underaction of both superior obliques on duction testing, A V-pattern esotropia of greater than 25 prism diopters, Brown Superior Oblique Tendon Sheath Syndrome, Chronic Progressive External Ophthalmoplegia (CPEO). [2] There are four anatomic regions which can be responsible for non-isolated CN IV palsies[2][9]: Diagnosis is made via the Parks-Bielschowsky three-step test. In the case of forced duction limitation, add an inferior rectus recession to the former. For example, with a right hypertropia, the potentially involved muscles include the right superior oblique, right inferior rectus, left inferior oblique and left superior rectus. The superior oblique and superior rectus muscles are intortors and the inferior oblique and inferior rectus muscle are extorters. 2015 Jul;26(5):357-61. A new treatment for A and V patterns in strabismus by slanting muscle insertions. High-resolution MRI demonstrated varied abnormalities in both congenital and acquired Brown syndrome such as traumatic or iatrogenic scarring, avulsion of the trochlea, cyst in the superior oblique tendon, inferior displacement of the lateral rectus pulley and fibrous restrictive bands extending from the trochlea to the globe (Bhola et al, 2005). The amount of suppression, which can vary from small suppression scotomas in binocular fusion to large suppression areas on the affected side and amblyopia, depends on various factors such as the size of the strabismus and age of onset. nerve palsy and Brown syndrome, it is instructive to briefly review the evolution in our understanding of Duane retrac-tion syndrome, the prototypical CCDD.