Anatomy.-The vitreous humor is the transparent, jelly-like structure occupying the space between the lens and the retina. The vitreous has somewhat of a depression on its anterior surface called the lenticular fossa in which rests the crystalline lens, and to the posterior capsule of which the vitreous is attached, while behind, it is adherent to the optic nerve. The presence of a hyaloid membrane inclosing the vitreous is claimed by some authorities; but, according, to others, the so-called hyaloid is identical with the internal limiting membrane of the retina, which according to Lieberkuehn, from the developmental standpoint, belongs to the vitreous. The structure of the vitreous has not with certainty been determined.
It is claimed that it can be split into concentric layers and various forms of cells have been found in it. These cells are toward the centre roundish in shape and more stellate or fusiform toward the peripheral layers of the vitreous. Chemically the vitreous is 98 per cent. water, with salts, extractive matter and a trace of albumin. Its consistency becomes less as age advances and in adult life in slightly more tenacious than the while of an egg. Its index of refraction is identical with that of the aqueous humor. A canal of about 2 mm. in diameter runs through the vitreous from the optic nerve to the centre of the posterior capsule of the lens, and during foetal life it contains the hyaloid artery. The vitreous contains neither blood-vessels nor nerves, and yet, on account of it cells, it must be considered an organized structure
Hyalitis Suppurativa.-Purulent inflammation of the vitreous may occur when a foreign body has penetrated into it, or it may be the result of an extension of some other inflammation of the eye and generally from an inflammation of the retina, choroid or ciliary body. It is now generally accepted that a primary hyalitis may occur and manifest itself either as an opacity or it may go on to suppuration. Pus may be found in the vitreous in some infectious blood diseases, and is due to exhaustion and debility. After cataract extraction or the removal of a staphyloma suppuration has been noticed as beginning in the prolapsed vitreous.
SYMPTOMS.-There may be bulging of the pupillary border of the iris and retraction of its periphery. Posterior synechiae are usually present and the tension is diminished. Together with the inflammation of the iris and ciliary body there is more or less pericorneal injection. Ophthalmoscopic examination will show a light yellowish reflex from the fundus, and when the pus is circumscribed, the appearance resembles very closely a glioma of the retina and is sometimes called pseudo-glioma. It is distinguished from the true glioma by the history, the appearance of the iris and the symptoms of iritis and by the diminished tension. The vitreous is hazy while in glioma it is clear.
COURSE.-Suppuration of the vitreous usually results in destruction of the eye. It generally becomes complicated with choriditis and often extends to a general inflammation of the eye or panophthalmitis. If the active process continues the eyeball ruptures and atrophy follows. Less severe inflammatory conditions of the vitreous, resulting in opacities and more or less destruction of vision may occur and, when it does, it is usually an extension from inflammation of other structures.
TREATMENT.-Hyalitis rarely occurs idiopathically, being usually associated with severe inflammations of the fundus, especially inflammation of the whole or part of the uveal tract. The treatment must then be directed to the primary disease. Particularly study the remedies recommended for choroiditis. Traumatic inflammation of the vitreous humor is more frequently observed, especially from a foreign body, which usually necessitates the removal of the eye.
When occurring in cases of great debility from low fevers and if seen in its earlier stages a stimulating, nourishing treatment may save the eye; but, as a rule, when pus has once formed in the vitreous the eye cannot be saved and enucleation is demanded.
Opacitates Vitrei (Myodesopsia, Muscae Volitantes, Synchysis, Synchysis Scintillans).-Opacities in the vitreous may vary greatly in form and size from a mere diffuse dust-like haziness to large membranous patches or strings. Their color may also vary from a gray to a decided black and they may be either fixed or floating in the vitreous. The diffuse opacities are often so transparent that they will simply appear to hide the retina as through a thin veil, or fine dust, and this form of opacity generally occurs in syphilitic retinitis or choroiditis. In other cases there will be such intense opacities of the vitreous as to obscure all reflex from the fundus, and the diagnosis is made by exclusion by oblique illumination, the presence of any opacity of the cornea, anterior chamber or lens. If this condition results from a haemorrhage, there may sometimes be seen on the posterior surface of the lens a red appearance from particles of blood which have become attached to the lens capsule. Membranous opacities may often be seen adherent by one or more points to the retina, choroid or disc.
SYMPTOMS.-The subjective symptoms depend upon the amount and density of the opacities. Thick, circumscribed opacities cause less impairment of vision than do thin and transparent but diffuse ones. Vision, therefore, may be not at all affected or wholly lost, but, in cases of floating opacities, varies according as the opacity is in the line of vision or not. Patients describe the appearance as gray or black spots of different sizes and shapes and often are able to draw pictures of their appearances.
Opacities of the vitreous are best determined by an examination with the direct method of the distance of about thirty centimetres and, as the patient moves the eye upward and downward, dark spots or streaks are brought into view in the red reflex of the fundus. The movement of the eye may have to be continued for some time before the opacity comes into view. The rapidity of the movement of the opacity increases in proportion to the fluidity of the vitreous and the movement continues after movement of the eye ceases. Vitreous opacities move in an opposite direction to the movement of the eye and cease as soon as the eye comes to rest. Opacity of the cornea or lens can be recognized by an oblique illumination.
COURSE.-Diffuse opacities may entirely clear up, or they may become aggregated into thick, circumscribed shreds, while the remainder of the mass becomes more transparent. The thick, circumscribed opacities may be somewhat absorbed but more slowly and obstinately.
CAUSES.-Opacities are especially found in myopes, with posterior staphyloma and choroidal changes. They are frequently due to some inflammation of the ciliary body, choroid or retina, or from an injury of the eye which has caused a haemorrhage into the vitreous. They have also in many instances been due to various general conditions, such as exhaustion after severe constitutional diseases, in anaemia, menstrual disturbances, syphilis, constipation, etc., and have frequently been seen where no cause can be given for their origin.
In muscae volitantes or myodesopsia there is no true opacity of the vitreous, and the black spots complained of by patients as floating before the eye when looking at a bright surface are due to shadows upon the retina produced by some normal elements in the vitreous or from small particles of secretions or tears moving over the cornea. In these cases there is no interference with vision and the ophthalmoscope shows no opacity. They will frequently cause great annoyance, especially in nervous individuals, and are generally attributed by the laity to biliousness or indigestion.
Synchysis is a fluidity of the vitreous and can only be diagnosticated by the rapid movement of opacities in the vitreous during motions of the eye. The tension of the eye is often diminished, but low tension does not necessarily indicate fluidity of vitreous, although soft eyeballs usually contain fluid vitreous. Synchysis is more often found in elderly people with staphyloma or choroidal disease. Synchysis, when present in cataract cases, may complicate the extraction by loss of vitreous.
Synchysis Scintillans is where the fluid vitreous contains numerous scales of cholesterin and tyrosin. When seen it presents, with the ophthalmoscope, a beautiful appearance, as of a shower of brilliant crystals. This condition seems to be associated usually with choroiditis, although it may be seen in eyes presenting no evidence of other disease. The vision, as a rule, is but slightly affected.
TREATMENT.-Dense membranous opacities may be torn with a fine needle, though operative measures are not usually required. If the opacity has been recent, especially if haemorrhagic, a compress bandage should be applied and the patient kept in bed.
If there has been haemorrhage into the vitreous humor, their absorption may be hastened by Arnica, Belladonna, Crotal., Hamamelis virg., Lachesis, Ledum or Phosphorus If the opacities are the result of inflammation of the choroid or retina, benefit has been derived from the following: Argentum nit., Aurum, Belladonna, Gelsemium, Jab., Kali iod., Kali mur., Kalmia, Lachesis, Mercurius, Natrum muriaticum, Phosphorus, Prunus, Sen., Silicea and Sulph.
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.