Hyperaemia of the Disc.- Simple congestion of the disc is evidenced by an increased redness, it assuming a general dull red hue which shades off into the surrounding fundus so that the outlines of the disc become blurred and indistinct. In addition to the appearance of the disc as seen with the ophthalmoscope, there may be some photophobia, fatigue on using the eyes or there pains around the eye. Hyperaemia of the disc occurs in all inflammations of the retina and choroid, and may be caused by refractive errors especially in hypermetropic and astigmatic eyes. It is also common in those exposed for a long period to the glare of a bright light. Cerebral hyperaemia fracture of the skull, of the morbid process at the base of the skull may result in hyperaemia of the optic nerve.
As the normal redness of the disc may vary being greater in plethoric persons and in those using alcohol to excess, it is always somewhat difficult to say when a abnormal congestion is present.
The treatment must be directed to the cause as it is more frequently symptomatic than idiopathic. The remedies especially to be considered are Belladonna, Duboisia, Phosphorus and pulsat.
Haemorrhage of the Optic Nerve.- When the extravasation occurs in the papilla it is readily seen. It is found to occur where the vessels have become degenerated, as in albuminuria, diabetes etc. It may also occur in embolism or thrombus of the central vessels and is perhaps most frequently seen in some form of neuritis or neuro-retinitis. In these cases the vision may be but little affected, unless the fibres going to the macula are involved, when the damage to sight is serious.
Haemorrhage into the sheath of the nerve behind the eye is more rare and generally results from injury as fracture of the base of the skull or of the orbit. The ophthalmoscopic signs are not at all indicative of the condition, as they may simply consist in a slight hyperaemia and haziness of the retina, or there may be all the characteristic signs of the embolism of the central artery. The vision is as a rule destroyed from atrophy
Neuritis Optica.- (papillitis, Choked Disc).- Inflammation of the optic nerve has been divided clinically into several forms viz.: papillitis or choked disc neuritis descendens or neuro-retinitis, and neuritis retro-bulbaris. As all but the last variety present ophthalmoscopic signs and very similar in appearances, as well as caused and pathological changes, they will be described under the general heading of neuritis optica, while to the last form, neuritis retro-bulbaris, we shall devote a separate space.
PATHOLOGY.- The changes in the nerve head consist first of a venous hyperaemia and oedema, followed by a hypertrophy of the nerve-fibres, lymphoid infiltration and an increase of the connective tissue, especially that of the neuroglia of the nerve and that surrounding the central vessels. There are also inflammatory changes in the trunk of the nerve and its sheaths. Tubercles ocular meningitis, and in suppurative meningitis pus cells are found not only in the spaces between the sheaths but also in the connective tissue of the nerve itself. In syphilitic neuritis there is thickening from hypertrophy and cell infiltration of the interstitial connective tissue and pial sheath. Later on the pressure from the increased size of the nerve results in an atrophy of the nerve-fibres. The atrophic changes of the nerve in choked disc are described at length by Ulrich. Archiv Ophthal., vol. xviii., I, 1889. In some cases where there is less thickening of the connective tissue gray atrophy ensues, in which the nerve-fibres are preserved, but become smaller through loss of their medullary sheath.
SYMPTOMS.- There are no external signs of neuritis excepting in some cases a dilations of the pupils and when present, is generally in those cases where central vision has been lost for some time, and in complete blindness the pupil is not only dilated, but is often immobile. Pain is only present in those cases due to some orbital affection when there may be some tenderness on pre-sure. There vision in neuritis is sometimes perfectly normal, and yet the ophthalmoscopic picture of inflammation of the optic nerve be quite characteristic. This fact illustrates the importance of an ophthalmoscopic examination in all cases, even though central vision be perfect. Usually there is, however more or less impairment of vision even to mere perception of light which may have come on quite rapidly or more often gradually. In some cases of an oedematous papillitis the vision will remain normal for several weeks and then commence to gradually fail, while in other cases it will be impaired from the first and steadily become worse.
The field of vision may be variously affected sometimes remaining normal, again it may become concentrically contracted, or it may be irregularly contracted in different sections. Hemianopsia, absence of half of the visual field may be present and be either horizontal or vertical and indicates the origin of the neuritis to be intra-cranial. There may be a central scotoma, due to an enlargement of the normal blind spot from swelling or there may be an abnormal scotoma due to involvement of the axial fibres. Color sense may or may not be lost and when it fails, generally does so in the usual order of green first, then red and blue last. The loss of color perception is generally proportionate with the loss of the central vision and affords an indication as to the course of the disease. If the vision and color sense fail gradually and proportionally, atrophy may be expected to follow and in cases where recovery takes place, the visual field and color perception return proportionately.
The Ophthalmoscopic Appearances very greatly but in every case there is hyperaemia haziness and swelling or wooliness, of the disc, with increase in the size of the central vein. In severe cases the swelling of the disc is excessive the central vein enormously distended and the artery contracted. Flame- shaped haemorrhages on or near the disc are often present and sometimes white spots of exudation are found in the retina. The media and remaining portions of the fundus are normal.
In papillitis, or Choked Disc we find in its simplest from a serous infiltration causing an excessive swelling with redness of the disc and engorgement of the retinal veins. To this may be added other inflammatory changes, resulting in a grayish exudation into the disc and surrounding retina with sometimes haemorrhages. When both eyes are affected one is usually more so than the other and one nerve is apt to be affected before the other. The swelling in a marked case of choked disc, due to serous infiltration forms an almost globular bright red mass of marked prominence projecting into the vitreous several mm., whose outlines shade off into the surrounding retina. The retina may or may not be infiltrated its arteries are small, but the veins are engorged. These cases are very similar to those of neuritis descendens and are most frequently found affecting both eyes, as is the rule in almost all cases of papillitis, when of intra- cranial origin. Monocular papillitis due to cerebral tumor usually affects the eye to the opposite side of the tumor but in all cases of neuritis affecting but one eye the cause is generally below the optic chiasm. Fick says choked disc is due less to inflammatory round cell infiltration than to the dilatation of the vessels, the saturation with serum and the thickening of the non-medullated nerve-fibres. Yet actual inflammation is never quite lacking and an infiltration with round cells and hypertrophy of interstitial tissue occurs or later.
In Neuritis Descendens or Neuro-retinitis the ophthalmoscopic appearances, while somewhat similar to those of papillitis, are not so well marked. There is less swelling of the disc, its outlines are indistinct the arteries small and the veins enlarged. (See chromo-Lithograph, Plate III Fig. 3) The disc is opaque and of a deep red color and there is apt to be an infiltration along the retinal vessels. There are often more extensive changes in both the nerve and retina; they become swollen and infiltrated, haemorrhages occur and white patches appear in the retina in the vicinity of the macula and disc. These patches in the neighborhood of the macula often assuming the stellate appearance seen in retinitis albuminurica.
COURSE.- The duration of optic neuritis will vary greatly in different cases. In some the disease will reach its height in two or three weeks, remain stationary for perhaps a similar period and then subside the nerve returning to its normal condition. These cases are often dependent upon a meningitis which runs its course before the neuritis may be said to have reached its height. Other and more severe cases may develop rapidly but the subsidence of the neuritis will be very slow- taking weeks or months and the symptoms are replaced by those of atrophy. A case of choked disc has been reported by Matthewson Trans. Fifth Internat. Ophthal. Congress, p. 613, 1876. in which the appearance of the nerve remained unchanged for three years.
Professor of Ophthalmology in the College of the New York Ophthalmic Hospital; Surgeon to the New York Ophthalmic Hospital. Visiting Oculist to the Laura Franklin Free Hospital for Children; Ex-President American Homoeopathic Ophthalmological, Otological and Laryngological Society. First Vice-President American Institute of Homoeopathy : President Homoeopathic Medical Society of the State of New York ; Editor Homoeopathic Eye. Ear and Throat Journal : Associate Editor. Department of Ophthalmology, North American Journal of Homoeopathy, etc.