Background: A small number of patients with ocular motility disorder suffer from myodystrophic disease. Clinico-pathological reports on the extraocular muscles of such patients are rare.
Case1: A 23-year-old woman complained of a 40 prism diopter (PD) exotropia and slight ptosis palpebrae OD. Adduction was restricted bilaterally. Chronic progressive external ophthalmoplegia was suspected. The medial rectus muscle, which was resected as a part of strabismus surgery, was examined by light-microscopy. Muscle fibers were atrophic and many ragged-red-fibers were present. Eye alignment was 8 PD exophoric at 14 months after surgery.
Case2: A 34-year-old man suffering from myotonic dystrophy presented with a 60 PD exotropia and bilateral ptosis palpebrae. Adduction was restricted bilaterally. Exotropia and ptosis OS were corrected surgically. Microscopic examination of the medial rectus muscle revealed increased adipose and collagen tissues. The muscle fibers were significantly reduced in diameter and contained multiple nuclei. The levator palpebrae muscle showed moderate atrophic change. The patient was 12 PD exophoric one month after surgery and 25 PD exotropic 8 months after surgery, and was satisfied with the results.
Conclusion: Whenever properly indicated surgical correction is useful in treating and diagnosing strabismus due to myodystrophy when combined with pathological examinations.
Nippon Ganka Gakkai Zasshi (J Jpn Ophthalmol Soc) 116: 657-663, 2012.