Acquired distance esotropia associated with myopia.

Background: Von Graefe (1864)(1) and Bielschowsky (1922)(2) described acquired progressive esotropia, with typically a larger angle for distance than near, associated with moderate myopia. This is unlike the esotropia seen in patients with high myopia.

Methods: We reviewed our patient records, finding 26 cases: 14 were female, 12 male. Age range at first presentation was 37-74 with a mean of 55.5. The myopia was from -0.75 to -10.00, with a mean of -5.50 in each eye. Eighteen patients mostly wore glasses, eight mainly wore contact lenses. All complained of horizontal diplopia. Seventeen (65%) had been treated with prisms with a gradual increase in power.

Results: Six patients (23%) continued with prisms although surgery has been offered in three cases. Seven patients (27%) had botulinum toxin to one medial rectus muscle. In two cases this proved to be successful maintenance therapy, the remaining five have gone on to have surgery. Seventeen (65%) have undergone surgery (mainly unilateral medial rectus recession and lateral rectus resection) with relief of diplopia and discarding of prisms. Three patients required further surgery for a recurrence after 10-12 years and another is using prisms for a recurrence after 11 years. One patient has suffered an early recurrence 6 months following surgery and is having his neurological work-up repeated.

Conclusion: This unusual sub-type of strabismus is a benign entity, which responds well to prism correction or surgery in cases who wish to wear contact lenses or whose prisms become inconveniently strong.