Discussion
The etiology of all double vision is due to an abnormality in the muscle, neuromuscular junction, nerve or the brain. Based on this, the correct source needs to be identified through specific evaluation. The Parks-Bielschowsky three-step test is considered the standard approach to identify a paretic muscle in a non-comitant deviation with a vertical component. In addition, a cover test in the nine positions of gaze must be completed to measure the vertical deviation and comitancy. Forced duction testing can physically attempt to cause ocular movement by grasping the insertion of a particular muscle with forceps and moving it. This will differentiate neurological from mechanical obstruction.1
The diagnosis is simple myopia and right Browns syndrome. The patient was prescribed the full spectacle prescription for his myopia and was educated that he could leave his glasses on for near work since his myopia and AC/A ratio help reduce his eye turn (exophoria) at near. Browns syndrome cases do not fit the Parks-Bielschowsky three-step criteria; however, the forced duction is positive.1-3
No treatment was required for his Browns syndrome. The patient and his parents were educated that sometimes these cases can undergo spontaneous recovery.1,2 Since he did not present with a significant hypotropia in primary gaze or an anomalous chin elevation, surgical correction was not considered.1-3
Current surgical techniques to repair this malady include silicone tendon expansion and superior oblique tenotomy.3 In acquired cases that coexist with inflammatory diseases, such as rheumatoid arthritis or lupus, it is recommended that these diseases be addressed first, since the disease processes themselves could initiate or perpetuate inflammation around the trochlea.3 Local and oral steroids have also been discussed in literature as having some value in these inflammatory cases.3
Besides acquired cases of Browns syndrome due to systemic diseases or inflammation, acquired cases are also plausible due to scarring of the trochlea secondary to trauma, superior nasal masses, or sinusitis.1,3 This patients prognosis was considered good because he did not have an anomalous head position and he had binocular vision in primary gaze without evidence of fundus torsion.13
1. Rutstein RP, Daum KM. Incomitant Deviations. In: Rutstein RP, Daum KM. Anomalies of Binocular Vision: Diagnosis and Management. Philadelphia: Mosby, 1998:306-9.
2. Griffin JR, Grisham JD. Other Oculomotor Disorders. In: Griffin JR, Grisham JD. Binocular Anomalies: Diagnosis and Vision Therapy (4th ed). Boston: Butterworth-Heinemann, 2002:246-7.
3. Wright KW. Browns Syndrome: diagnosis and management. Trans Am Ophthalmol Soc 1999;97:1023-109.
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