Orbicularis Oculi Muscle in Chronic Progressive External Ophthalmoplegia

Exotropia Surgery in CPEO

“…Although these fibres are normally present in limited numbers in the extraocular muscles, including the orbicularis oculi, in the mitochondrial myopathies they occur in a significantly greater proportion of muscle fibres in association with an increase in fibre variability and fibrosis, and less often with myonecrosis. [4][5][6] Similar to reports in patients with CPEO and limb weakness, the few published reports of electron microscopic studies of ocular muscles document the frequent presence of ultrastructural abnormalities in the mitochondria of these ragged red fibers. 3,6-8 Not only is there an increase in size and pleomorphic configuration of the excessively accumulated mitochondria but alterations in the cristae and matrix are the rule.…”

Frontalis sling operation using silicone rod for the correction of ptosis in chronic progressive external ophthalmoplegia

“…Clinical findings are slowly progressing ptosis, extraocular movement disorders, poor Bell’s phenomenon and poor lid closure 1 2. Surgical treatment for ptosis in these patients is generally considered when the visual axis is obscured by the ptotic eyelid or when the ptosis is cosmetically unacceptable 3.…”

Orbicularis oculi muscle biopsies for mitochondrial DNA analysis in suspected mitochondrial myopathy

“…Levator palpebrae muscle biopsies have sometimes been used diagnostically but often give inadequate results due to the small volume of tissue available for diagnostic testing6 and the technical difficulty in reaching the belly of the muscle deep in the superior orbit. There has been very little written about the use of orbicularis oculi muscle biopsies in patients with a suspicion of a mitochondrial disorder6 8 and no previous reported attempts to perform mtDNA analysis on orbicularis specimens.…”

“…While the morphological changes in limb muscle biopsies that are associated with mitochondrial disorders have been shown to be present in orbicularis oculi muscle in normal controls and thus may not be specific,8 the demonstration of an mtDNA abnormality is diagnostic.…”

“…The use of orbicularis oculi muscle to assist in the diagnosis of CPEO was first described in 1980 by Eshaghian et al 8 who concluded that RRF are more abundant in CPEO patients, but that some RRF are also seen in controls. In 2009, Almousa et al 6 developed a protocol for orbicularis oculi muscle biopsies that involved suturing samples of muscle on wooden cotton buds to keep them at isometric length to minimise the contraction artefact.…”