Herpes zoster ophthalmicus and post-herpetic neuralgia.

Jonathan Hutchinson (1865-6) was the first person to distinguish herpes zoster ophthalmicus from erysipelas, and he described 18 cases, one of which developed a third nerve palsy. Hutchinson stated that zoster never affected the cheek at all, but a few years later Head and Campbell (1900) described a case with affection of the mandibular branch; Paton (1926) reported a case with involvement of both cheek and forehead; and O'Neill (1945) described what he considered to be the first case with involvement of the first, second, and third divisions of the trigeminal nerve, but in his case there was also involvement of the seventh and eighth cranial nerves. Various palsies of the extraocular nerves may occtur, and the incidence according to WorsterDrought (1923) is 7% of cases with ophthalmic herpes zoster. The commonest nerve to be paralysed according to Moore (1932) is the third, and forms 74%" of the extraocular nerve pareses Edgerton (1942) states that the third nerve was the commonest extraocular nerve to be paralysed and occurred 96 times in the literature. Edgerton (1942), in his review of the literature, stated that paralysis was found usually after, sometimes with, and occasionally before, the skin eruption; he goes on to comment that paralysis of the extraocular nerves is due to " encroachment of the inflammation in. the region of the cavernous sinus" : this is probably incorrect as the lesion has been shown to be in the anterior horn cells when muscular paralysis occurs elsewhere, so there is no reason to postulate a different pathology so far as the eye palsies are concerned. Other cases of herpes zoster ophthalmicus with intraocular or extraocular muscular palsies have been described by ParkesWeber (1916), Hall (1903), and Mules (1903). Mules also suggested that ocular palsies could occur without an eruption of zoster, i.e. formes frustes. Batignani (1934) reported a case of moderate exophthalmos with total ophthalmoplegia; Car-