A manual of medicine.

  • Allchin, William Henry, 1846-1912.
Date:
1901
Catalogue details

Licence: In copyright

Credit: A manual of medicine. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    that the pupil becomes quite inactive to light as well as contracted, but it may still retain its contractility with accommodation—a condition to be presently alluded to as the Argyll-Robertson pupil. Myosis may also result from excessive vascularity of the iris, as in iritis, or when a foreign body is present on the cornea. Mydriasis or dilatation of the pupil, the opposite condition to myosis, may also arise. That too may be irritative or paralytic — the former arises from irritation of the mechanism upon which dilatation depends, viz. the sympathetic chiefly, and it may be present as a result of irritative disease in the neck or in any part of the sympathetic path, in blood states which probably act as sympathetic irritants, e.g. anaemia and chlorosis, or it may arise by diminishing the vascularity of the iris, and it is also said, with doubtful truth, in conditions of increased intracranial pressure. Paralytic mydriasis, on the other hand, is the result of paralysis of the pupil-contracting centre and of interference with the path by which stimuli are transmitted to that centre. Thus disease of the third nerve nucleus or intraocular tumours may cause it. It has also been found in thrombosis of the cavernous sinus and in cases in which there has been pressure on the ciliary nerves. It also of course occurs in most cases of optic atrophy, and it occurs after excessive haemorrhage. One of the most important and significant modifications of the pupil occurring as a result of disease is that already alluded to as the Argyll-Robertson pupil, also known as reflex iridoplegia. In this condition there is often myosis, but this is not invariable. The essential of the condition is that the pupil while still reacting well during accommodation does not react at all—or so slightly as to have the same significance — to fight. The pupils are frequently unequal, sometimes they are irregular in shape, e.g. oval instead of round. As a rule, when the Argyll-Robertson pupil is present it is so in both eyes. Occasionally, however, it is uniocular. It is a condition which usually occurs in association with tabes dorsalis ; not infrequently it is also found in general paralysis, and exceptionally, in other cerebral and spinal diseases. It may be present without other obvious morbid conditions of the nervous system, but it is usually significant of at least a degenerative tendency in the nervous system. Its frequent association with diseased conditions of the nervous system, usually regarded as syphilitic or para-syphilitic, and its occurrence as an isolated phenomenon in patients with a syphilitic history, make it probable that this disease has a close causal connection with it. Another morbid condition is that which occurs after diphtheria, and it is almost the converse of the Argyll-Robertson pupil, the condition, namely, in which there is paralysis of accommodation and consequent inability to read or see clearly at a near distance, while reaction to light is present. Rarely this is an isolated phenomenon ; more com- monly it is associated with other evidences of post-diphtheritic paralysis,