MEDICAL OPHTHALMOLOGY.
MEDICAL OPHTHALMOLOGY.
BY WM. F. NORRIS, M.D.
INTRODUCTION.—The object of the following essay is to give, as far as practicable in the limits of an encyclopædic article, an account of the eye symptoms which may be seen in the course of diseases of the general system and in connection with the pathological conditions of the various organs of the body. The eye has always been looked on as a valuable indicator of general systemic disturbance. Its expression has been noted as showing the general vigor or feebleness of the patient, as well as his varying mental moods, while paralysis of its external and internal muscles has in all times been regarded as a sign of disturbed intracranial action or disease. In order to judge of the state of the circulation the physician habitually looks at the lips, the tongue, and the nails, where the capillaries are covered by translucent material, to appreciate the state of the circulation. How much better are we enabled to do this when, by the use of the ophthalmoscope, we look at the interior of the eye and see the blood-columns in the veins and arteries of the head of the optic nerve and the retina laid bare to our view without any opaque covering whatever! Such an examination, besides showing the state of the circulation, will frequently reveal a neuritis which may be due to some intracranial disease, or show a degeneration of the optic nerve which may point to impaired power and tissue-change in the spinal cord or the brain; or there may be characteristic retinal changes associated, as, for instance, with disease of the kidneys, or extravasation of blood which may be dependent on general or local causes; these frequently serving as important indices of the state of the nerves and vascular tissues in other organs in the body.