Clinical features and refractive profile of Brown syndrome

Understanding the refractive profile, amblyopia prevalence, binocular status, and head position in patients with Brown syndrome help clinicians become more familiar with this syndrome.

Brown syndrome is identified as an active and passive restricted elevation of the eye in adduction. There is little information on clinical features, including refractive status, amblyopia, abnormal head posture (AHP), and types of deviation in these patients.

This study retrospectively evaluated records of 100 Brown syndrome patients from 2015 to 2022 at Farabi Eye Hospital, Iran.

The mean age was 6.99 ± 6.33 years, including 48 (48%) males. A congenital source was found in 74 (74%) and 96 (96%) patients had unilateral involvement. The mean CDVA for the affected and non-affected eyes were 0.05 ± 0.11 and 0.03 ± 0.06 logMAR, respectively (P = 0.31). In unilateral cases, hyperopia, myopia, and emmetropia were observed in 55 (57.29%), 2 (2.08%), and 39 (40.63%) affected eyes, respectively. The most common type of deviation was pure hypotropia, which was found in 53 (53%) cases, followed by 'combined exotropia and hypotropia' observed in 26 (26%) patients. The mean angle of hypotropia and horizontal deviation in the primary position at distance was 12.10 ± 8.50 and 8 ± 13.20 prism dioptre, respectively. A V-pattern was found in 76 (76%) patients. Amblyopia was observed in 13 (21.67%) of 60 cooperative patients, and AHP was noticed in 66 (66%) patients, in which "combined chin up and contralateral face turn" was the most common type.

About 75% of cases were congenital, 50% had pure hypotropia, 75% showed V-pattern, 20% had amblyopia, and AHP was observed in 67% of patients. The remarkable prevalence of amblyopia alongside the high occurrence of AHP should alert clinicians to carefully assess patients with Brown syndrome for sensory fusion and amblyopia.