OPTIC NEURITIS. Inflammation of the optic nerve may be (1) papillitis, in which the optic disk is affected, or (2) retrobulhar neu ritis: in which the disk is hut slightly involved and the changes are in the nerve fibres behind the eye. In papillitis both eyes are usually involved, most frequently as the result of brain tumor, meningitis, abscess of the brain, or hydroceph alus. Syphilis is a common eause. and less fre quently acute febrile affections. general diseases and inflammations in the region of the eye. The only subjective symptom is impairment of vision. The ophthalmoscope ( Tv.) shows a condition known as choked disk. in which the optic disk is swollen, its edges indistinct and fringed. the veins di lated and torturous. or less projection of the disk and involvement of more of the surrounding retina. The inflammation runs a chronic course and may terminate in recovery or he followed by atrophy of the nerve with consequent loss of sight to a varying degree. Retrobulbar neuritis
may be acute or chronic. The former is rare, and results from rheumatism. syphilis, exposure. acute infectious diseases. and poisons. There is neuralgia, pain in the eye and near it, rapid loss of sight. while even ophthalmoscopic examination shows little or nothing. Sight usually returns within a few months, hurt often with a central scotoma ; sometimes there is partial or total blindness. The chronic form is usually the re sult of excessive use of tobacco and alcohol, separately or combined. Both eyes have gradual ly diminished vision. (See AmilLvort.k.) If the patient gives up the use of the drug causing the neuritis complete recovery may occur; on the other hand, there may be partial loss of sight.