Benefits of retroequatorial four horizontal muscle recession surgery in congenital idiopathic nystagmus in adults.

INTRODUCTION: Four muscle surgery for congenital nystagmus was originally described in 1956 and popularized by two articles in the 1990s. A review of the literature revealed only three studies of seven, nine, and six patients published since then. We therefore reviewed our patients to determine the objective and subjective benefits of this procedure. METHODS: A retrospective review was carried out on patients who underwent bilateral maximal horizontal muscle recessions for congenital nystagmus between 1997 and 2002. Improvement in visual acuity was documented. An external assessor administered an anonymized questionnaire to discover any perceived benefit. Eighteen patients were identified, 12 men and 6 women, with an average age at surgery of 32 years. RESULTS: Preoperative visual acuity ranged from 6/9 binocularly to 6/60. All underwent bilateral medial rectus muscle recessions of 8 mm to 10 mm and bilateral lateral rectus muscle recessions of 8 mm to 12 mm. Nine patients (50%) gained one line of Snellen visual acuity. There were four complications: one scleral perforation; two developed exotropia; and one complained of asthenopic symptoms. This latter patient was the only one who experienced some deterioration of vision acuity. Fourteen of 18 (78%) questionnaires were returned. Eight patients said they were pleased; four were indifferent and two were displeased. CONCLUSIONS: We conclude that this operation delivers limited objective benefit. None of our patients were able to obtain a driving license. Fifty-seven percent of patients expressed the view that they were glad to have had the surgery, although the visual improvement was only slight.