2020–2021 BCSC Basic and Clinical Science Course™
6 Pediatric Ophthalmology and Strabismus
Part I: Strabismus
Chapter 12: Special Motility Disorders
Miscellaneous Special Forms of Strabismus
Chronic Progressive External Ophthalmoplegia
Chronic progressive external ophthalmoplegia (CPEO) is a rare form of mitochondrial cytopathy that can affect various body systems. It usually begins in childhood with ptosis and slowly progresses to total paralysis of the eyelids and EOMs. CPEO may be sporadic or familial. Although a true pigmentary retinal dystrophy is rare, constricted visual fields and electrodiagnostic abnormalities can occur. The diagnosis of CPEO is confirmed when muscle biopsy results show ragged red fibers or when specific alterations of mitochondrial DNA are detected. Kearns-Sayre syndrome is characterized by retinal pigmentary changes, CPEO, and cardiomyopathy (especially heart block).
See BCSC Section 2, Fundamentals and Principles of Ophthalmology, Section 5, Neuro-Ophthalmology, and Section 12, Retina and Vitreous, for additional information on these and other mitochondrial disorders.
It is important to ensure that the patient’s cardiac status is evaluated, because life-threatening arrhythmias can occur in Kearns-Sayre syndrome. Treatment options for the ocular motility disorder are limited; small surgical series report a high rate of long-term undercorrections. Cautious surgical elevation (suspension) of the upper eyelids can lessen a severe chin-up head position.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.