Haziness of the Cornea is usually present in all forms of glaucoma, excepting in glaucoma simplex, when it may be absent. The haziness is uniform, but most intense at the centre, and often shows a dull, stippled appearance of the surface. Haziness of the cornea either disappears immediately or soon after the tension becomes normal again. The haziness is due to an oedema of the cornea, and its rapid disappearance on the return of normal tension is owing to the elasticity of the cornea.
Anaesthesia of the Cornea is found in almost all cases of chronic glaucoma, and is apt to be more complete at some points than others. This anaesthesia is explained by Fuchs as due to an increased amount of fluid in the nerve channels, causing a distension and that the nerve-fibres become paralyzed by the infiltration and pressure from this fluid, at some places he has found the nerve-fibres torn asunder.
Dilatation and Inactivity of the Pupil-This is a very constant symptom of glaucoma. The pupil is often oval or egg- shaped and, in this respect, differs from the dilation in optic nerve atrophy when it is usually circular. the cause of the dilatation has been attributed to a paresis of there ciliary nerves from the pressure, and also, by some, to a constriction of the vessels of the iris. the irregularity of the dilatation is supposed to be due to a firmer attachment of the iris to the sclera at some points than at others.
The green Reflex from the Pupil is due to the bluish-white tinge from the haziness of the cornea and aqueous, combined with the physiological yellow tint of the lens caused by age
Shallow Anterior Chamber-This is due to a pushing forward of the lens and iris and in old cases to the peripheral adhesion of the iris to the posterior surface of the cornea. In may be so shallow in some cases as to render an iridectomy very difficult.
The Haziness of the Humors is very slight and diffuse and is due to the increased amount of fluid within the eye.
Enlargement of the ciliary Veins due to the compression upon the venae vorticosae, causing a damming up of the blood, which has to pass off through the anterior ciliary veins.
Pulsation of the Retinal Veins may be physiological and is found in normal eyes. It is due to a transmission of the arterial wave through the vitreous, and is apparent at the papilla because the veins bend and are contracted at this point. The walls of the veins are thin and the pressure from the vitreous causes a momentary stoppage of the circulation until another arterial wave pushes the blood forward again. It is also noticed, in some instances, where an artery crosses a vein and the pulsation is then given direct to the vein. when absent, it may be owing to a hypertrophy of the walls of the artery, and, hence, no pulsation. As venous pulsation may be seen in normal eyes, it is not of special diagnostic value.
Pulsation of the Retinal Arteries at the Disc.- There is, of course, a normal physiological pulsation of the arteries, but it is so slight as not top be seen in normal eyes, yet it may be produced by pressure upon the globe with the finger. It is so rarely seen under other circumstances that, when present, it is claimed by some to be almost pathognomonic of glaucoma. It is due to a resistance to the flow of blood, the current only being complete during systole. this resistance is caused by the increased intra-ocular pressure and possibly, as claimed by some, to an active spasmodic constriction of the vessels themselves. The absence of arterial pulsation in some cases is due to hypertrophy of the walls of the arteries.
Pain-This symptom varies from a slight sense of fullness or dragging to a most severe acute neuralgia over the whole region supplied by the fifth nerve, and may be associated with general symptoms of pallor, fever, nausea and vomiting. The cause of the pain is pressure upon the nerves from the increased tension. In acute attacks the pain may be an intense agony associated with symptoms of great depression. In sub-acute cases the pain is less marked, while in chronic cases there may simple be a sensation of fullness or discomfort.
Swelling of the Lids, Chemosis and Exophthalmos are all due to infiltration from the pressure.
Contraction of the field of vision is usually a loss of the inner or nasal side first, followed by a loss of the lower, than the upper part of the field, showing an affection first of the temporal or outer half of the retina and then of the upper and lower quadrants. This order of retinal affection is due to the vascular distribution. The temporal portion of the retina being less freely supplied with vessels, it becomes first affected from the pressure obstructing its capillary circulation. there is, however, in affected, as there may be concentric restriction of the entire field, or sectional defects, and even in some cases a central scotoma with the periphery of the field remaining good. the color fields are usually contracted proportionate with the form fields.
Excavation of the Optic Disc- More or less cupping of the disc is met with sooner or later in all forms of glaucoma, but it bears no close relation to the loss of vision. It is the result of the intra-ocular pressure upon the lamina cribrosa, which becomes pushed backward, and, when complete, the vessels are pushed to the inner or nasal side, the veins are large and the arteries small, the vessels bend sharply over the edge of the disc, becoming lost of view and reappearing again at the bottom of the cup, and the disc itself appears of a grayish-blue color. (See Chromo-Lithograph Plate III, Fig.12) Surrounding the papilla is a narrow yellowish white ring, due to atrophy of the choroid. By an examination with the indirect method we can determine by the parallax test slight degrees of excavation. this shows, upon moving the object lens from side to side, an apparent movement, the edges of the papilla seeming to slide back and forth over the center. From this we know that the edge of the papilla lies nearer to the eye of the observer than its centre. the depth of the excavation can be approximately estimated by the direct examination, allowing 3 D. to every millimeter of depth.
It is important to distinguish the excavation of glaucoma from that occurring physiologically and from atrophy of the nerve. (See Chromo-Lithograph Plate II., Fig.2, and Plate III., Figs. II and 12)
The Physiological cup is white, occurs in a normally tinted nerve-head and never involves very much of nasal part of the disc over which the vessels can be seen to course. The vessels can always be followed down the side of the cup, which is funnel shaped and not deep like the cup of glaucoma.
The cup in Atrophy of the Nerve is shallow and usually involves the whole of the disc. The vessels never bend sharply over its margins. The nerve-head is abnormally white from diminished capillary circulation.
The Cup of Glaucoma is abrupt and deep, the vessels disappearing at its edge. there is a crowding of the vessels to the nasa-side. it often has a greenish hue, and there is usually a yellowish choroidal ring around the papilla.
The impairment of Vision varies considerably. In every acute attack it fails rapidly and then recovers somewhat when the symptoms subside, but each attack causes a little more destruction than the preceding one, until finally it becomes completely lost. The loss of vision is due to pressure upon the nerve elements of the retina and optic nerve, excepting in those cases where the loss of vision is sudden and complete, when it may result from an ischaemia of the retina.
Photopsia, or subjective sensations of light, is an inconstant symptom which may be present especially during attacks and may persist even after complete blindness and is probably due to a dragging upon the retina.
COURSE-The history of a case of glaucoma will usually show a longer or shorter period of premonitory symptoms. This prodromal stage may have extended over several weeks or months, and then there will occur a sudden attack of acute glaucoma, lasting from a few hours to several days, when the symptoms subside and the eye returns to normal or nearly so. These attacks return, the intervals becoming shorter and shorter, the vision more and more impaired until finally it leads to a chronic or absolute glaucoma. In some cases an acute attack may continue directly into an absolute form without any subsidence of symptoms. Glaucoma does not lead to spontaneous cure, but tends, if unchecked, to absolute blindness.
CAUSES-The statistics of glaucoma show it to form about one per cent. of all eye case, varying, however, in different countries and different clinics. It is especially a disease of old age, some claiming that an attack of primary glaucoma under the age of thirty-five is extremely doubtful. Glaucoma simplex may occur in young people and it is also found in myopic eyes.
Sex seems to have little or no influence, and in some cases it seems to be hereditary. Hypermetropia predisposes to glaucoma, 50 to 75 per cent. of the cases being found in hypermetropic eyes.
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.