Role of Botulinum Toxin A in Cyclic Esotropia – A Long Term Follow up
Ayse Ipek Akyuz Unsal, MD1; Seyhan B. Ozkan, MD1; Sule Ziylan, MD2
1Adnan Menderes University Medical School, Department of Ophthalmology, Aydin/ Turkey
2Yeditepe University Medical School, Department of Ophthalmology, Istanbul/ Turkey
Introduction: Cyclic strabismus is a rare entity with unknown etiology. The few case reports with the use of Botulinum toxin A (BTXA) did not include the long term outcome. We herein report two cases of childhood cyclic esotropia who underwent BTXA treatment with a follow up at least 8 years in an attempt to demonstrate the long term outcome of BTXA treatment.
Methods: Two cases who presented with sudden onset cyclic esotropia at 2 and 4 years of age were included. BTXA injection was performed into appropriate muscles. Follow up was 8 and 9 years.
Results: Case 1 was a 2 year old boy with left dominant alternating esotropia on a cyclic basis. The squint ranged between 25-45 prism diopters (PD) at near and distance. He underwent BTXA injection into the left medial rectus muscle. He became orthotropic at near and distance with 60 sec arc stereopsis. During the 9 years follow up, he remained stable. Case 2 was a 4 year old girl with the complaint of double vision and squint. Her deviation was 40 PD at near and 35 PD at distance on a cyclic pattern. She underwent bimedial BTXA injection and became orthotropic with glasses. During the 8 years follow up she remained stable with 120 sec arc stereoacuity.
Discussion: Considering the consecutive and recurrent deviations with surgical treatment in previous reports, BTXA seems to be a more appropriate first line option for treatment of cyclic deviations despite the limitations of a non-comparative assumption.
Conclusion: Our results suggest that BTXA is effective to break the cycle permanently in cyclic esotropia.
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