A 26 yrs old male with restriction of eye movements in all directions and moderate ptosis but with no diplopia or squint. Diagnosis is:

Bilateral ptosis without diplopia is seen in chronic progressive external ophthalmoplegia (CPEO). Multiple cranial nerve palsies as in cavernous sinus syndrome & orbital apex syndrome, present with diplopia with ophthalmoplegia and other symptoms. Ptosis & diplopia are presenting symptoms in approx 50% of patients of Myasthenia gravis. Chronic progressive external ophthalmoplegia (CPEO): The most common mitochondrial myopathy in which ophthalmoplegia is a prominent feature is chronic progressive external ophthalmoplegia (CPEO) Clinical Features: The main features of this syndrome are ptosis, limitation of eye movements, and diplopia. Ptosis is the first sign. It is bilateral and symmetrical. Ocular motor defects are symmetrical and slowly progressive so patients are not aware. Downgaze is the last to be affected. Kearns sayre syndrome: triad of chronic progressive external opthalmoplegia,pigmentary retinopathy and hea block. Diagnosis: Muscle biopsy: CPEO is diagnosed through muscle biopsy. On examination of muscle fibers stained with Gomori trichrome stain, accumulation of enlarged mitochondria is seen as dark red staining "ragged red fibers" Polymerase chain reaction: finds the mitochondrial mutation. Treatment: There is no specific treatment. Surgery for ptosis and diplopia can help the patient. Ref: 1) Yanoff & Duker Ophthalmology, 3rd Edition, Page 1399-1340, 1019; 2) Harrison's, Principles of internal medicine, 17th Edition, Page 192, 192, 901, 2690, 2673, 2234;