CHAPTER XII THE VITREOUS
Troubles in the vitreous are characterized by the formation of opacities which may be of nearly any size and may or may not interfere with vision. Sometimes the vision is obscured by a multitude of these opacities, each of which is so minute that it cannot be seen by itself, but taken together form a cloud. The presence of others which are too minute to be detected is inferred from the complaint of specks and hairs floating before the eyes. Other opacities are large enough to be visible with the ophthalmoscope and are either fixed or float about.
<Callout type="important" title="Important">Generally speaking it may be said that any opacities in the vitreous that can be seen with the ophthalmoscope, or are in sufficient numbers to obscure the vision, are indicative of serious trouble within the eye.</Callout>
The only congenital malformations to be observed do not really pertain to this tissue, but simply project into or through it, and are described here only because they are detected, as a rule, in the course of a systematic examination of the vitreous.
REMAINS OF THE FETAL HYALOID ARTERY
During an ophthalmoscopic examination we occasionally have the opportunity to observe a grayish tag or strand extending into the vitreous from the papilla, or from the posterior pole of the lens, sometimes joining the two. The vision may or may not be affected, but often the eyes are ill developed and amblyopic, frequently microphthalmic. Such a tag or strand is composd in most cases of the remains of the fetal hyaloid artery, or of its sheath. Rarely it contains blood and a pulsating stump projects from the papilla into the vitreous; still more rarely the blood column reaches to the lens, when we shall find on the posterior surface of the latter some remains of the fetal vascular membrane.
<Callout type="warning" title="Warning">When the vascular cord does not extend as far as the lens we should examine it carefully to distinguish it from another congenital anomaly in which a loop starts from the central artery in the papilla, extends out into the vitreous and then returns, the ascending and descending portions twisting about each other in their course. This does not seem to be related in any way to the hyaloid artery, though it may readily be mistaken for it, but is simply an anomaly in the course of a branch of the central artery.</Callout>
The only other congenital anomaly that we are at all likely to see in the vitreous is the presence, in microphthalmic eyes, of bands or masses of fibrous tissue, which usually are associated with remains of the hyaloid artery.
MUSCZE VOLITANTES
Often a patient is distressed because of one or more spots of fantastic shape that move about in his field of vision. He may have been reading or writing when his attention was attracted by a peculiar spot that floated down near his line of vision, moved out of sight when he tried to look at it, and reappeared as soon as he returned to work. Probably he noticed several of these spots. We find the eyes perfectly healthy, his vision good, can detect no opacities anywhere in the refractive media, and are able to assure him confidently that the spots are in no way symptomatic of any disease which threatens the integrity of the eyes. We call them musce volitantes.
<Callout type="tip" title="Tip">They may appear suddenly and persist for many years without apparent change, or they may appear and disappear from time to time, and many persons are able to detect them at any time that they wish to look for them.</Callout>
Their appearance seems to be more noticeable when the eyes are strained or overworked, and in conditions of bodily weakness or fatigue, so it is possible that such conditions render the perceptive apparatus hypersensitive to the shadows cast by these minute defects in the vitreous.
274 DIAGNOSIS FROM OCULAR SYMPTOMS
Musce volitantes must be differentiated from true opacities, whether fixed or floating. When a patient tells us that while he is looking quietly at a certain point in a white surface a black spot is always present in exactly the same relation to his visual line, the spot must be caused by a fixed opacity somewhere in the refractive media, and probably we shall find it in the lens, so the first thing we have to do is to have the patient observe whether any of the spots of which he complains keep a fixed position when his eyes are quiet. If none of them do this we can dilate the pupil so as to get a clear red reflex from the fundus with the ophthalmoscope held several inches away from the eye, have the patient move his eyes quickly up and down a few times and then hold them quiet. If no black specks can be seen to sink across the red reflex we know that no visible floating opacities are present in the vitreous, and, as the eyes are healthy and the vision good, the diagnosis of musce volitantes is positive.
FLUID VITREOUS
If on the contrary we see black opacities sink across the red reflex we know that we have to deal with a pathological condition, and that the vitreous is more or less fluid. Almost invariably the vision is impaired to some degree in these cases. The degree of fluidity may be estimated roughly from the rapidity with which the opacities move; if they pass rapidly across the field the larger part of the vitreous is fluid, but if they move slowly the liquefaction is slight, or not so far advanced.
When the nutrition of the vitreous is impaired by inflammatory or other causes it tends to become fluid, with the formation of opacities that are shaken about in the fluid by the movements of the eye and sink to its lowest part when the organ is at rest. The presence of floating opacities leads us to investigate closely for their cause, as they are met with during and after inflammation of the uvea, especially choroiditis, in some cases of retinitis, in high myopia, after hemorrhages, and after wounds of the eye.
<Callout type="risk" title="Risk">In these cases we need to take careful note of the tension of the eye from time to time, and to observe whether there is any increase in the rapidity of the movement of the opacities across the field. The tension of the eye may be normal, or it is increased when glaucoma is present, but generally a soft eye is an indication that the vitreous is fluid.</Callout>
An increasing fluidity, with a tension which is continually becoming lower, after any inflammation is a bad prognostic sign, as it indicates the onset of atrophy, but atrophy is not to be feared as long as the tension remains normal.
When we find little opacities that float slowly in the eye of an elderly patient it is well to examine his lens in search of an incipient cataract, as such floating opacities frequently accompany that condition. The reason for their appearance is not understood, but they do not seem to be in any way a bad prognostic sign.
In other old people, sometimes after the extraction of a cataract, we see opacities that reflect the light and look like brilliant spangles as they dance about or sink through the vitreous. This is called sparkling synchysis, or synchysis scintillans. The opacities are formed of crystals, mainly of cholesterin, but whence they originate, or how they come to be formed in the vitreous, is unknown. Usually the eyes otherwise are healthy.
HYALITIS
When the vitreous is very hazy we are accustomed to say that the patient has hyalitis, although there is no such thing as an inflammation of the vitreous. The cloudiness may be so dense that we can see only a red reflex from the fundus, perhaps not even this, but in most cases we are able to see the details of the fundus indistinctly, while the papilla looks unusually red.
<Callout type="important" title="Important">Not infrequently the picture presented by the papilla resembles closely that of a neuroretinitis, but we are able in most cases to make the differentiation at once by turning our attention to the periphery of the fundus, for this appears normally clear, as a rule, in neuroretinitis, while it is obscured equally with the center in hyalitis.</Callout>
The cloudiness is due to the presence of an immense number of opacities which are so minute that no one of them can be perceived with the ophthalmoscope, although together they obstruct the vision. When they are comparatively few they are apt to be very difficult to detect, for then they may scarcely interfere with the transparency of the vitreous.
276 DIAGNOSIS FROM OCULAR SYMPTOMS
In other cases of hyalitis we see filmy patches in the diffuse haze, or distinct opacities here and there. Occasionally the latter may be very large, and some of them may adhere together so as to form membranes. In rare cases a dull yellow reflex from within the eye informs us that suppuration is present, and that the patient has an abscess of the vitreous, or a suppurative hyalitis.
This is to be differentiated from a glioma of the retina and a pseudoglioma, both of which give a yellow reflex from deep in the eye, by the history of a wound, or the presence of some septic disease or focus from which an abscess has started by metastasis, together with the age of the patient, and the history.
With the recession of the primary inflammation an ordinary hyalitis may clear up, the opacities become absorbed, and the vitreous regain its transparency, or the latter may become more or less fluid with permanent floating opacities.
HEMORRHAGE INTO THE VITREOUS
When an eye has suffered a great loss of vision, either spontaneously or after a traumatism, and we can get little or no red reflex from the fundus, but by oblique illumination can see a red mass, or at least a reddish appearance behind the lens, we know that a very large hemorrhage has taken place and occupies a great part of the vitreous.
In another patient we may see a black mass with red borders, or a red mass lying in front of the retina. In still another, whose vision is not quite so badly impaired, we may see a bright red film between us and the fundus, and, when this film lies in front of the macula, the patient may state that objects seem to him to have a reddish color.
Occasionally, but not often, we can see the place where a retinal vessel has been ruptured. Our most important duty in such a case is to learn the cause of the hemorrhage. This is self evident when the eye has been wounded, or has received a blow, but when the hemorrhage has occurred spontaneously, or has followed a severe bodily exertion, the cause must lie in an abnormal condition of the blood vessels, or of the blood itself, and can be traced to a general or a local disease. Arteriosclerosis is the cause in many old people, but we should always make a thorough examination to exclude more active diseases.
The walls of the vessels may have been weakened by syphilis, or by an excessive indulgence in alcoholic liquors. Both the urine and the blood should be examined, for the patient may be found to be suffering from diabetes, or perhaps from renal disease, and such hemorrhages occur in anemia, chlorosis, and leucocythemia.
They have been observed also in pregnant women. Sometimes they occur in emphysema of the lungs, when it seems to be probable that the respiratory effort serves to rupture a blood vessel which has been weakened by some other disease. When no other cause is apparent we should remember that the claim has been made that a hemorrhage into the vitreous may be the first sign of a tuberculosis of the ciliary body.
Such local diseases as high myopia, choroiditis, and retinitis furnish an adequate explanation of a hemorrhage into the vitreous when they are known to have been in existence in the eye prior to its occurrence, and when other evidence of the presence of such a disease is clearly manifest, but when the previous history is unknown and the hemorrhage is large, we frequently are obliged to wait until at least a part of the blood has been absorbed to establish such a cause.
These hemorrhages are absorbed very slowly. The vitreous itself becomes more or less fluid, and a part of the blood may remain for a long time in the form of large or small floating opacities. Sometimes the hemorrhages recur several times, and then connective tissue is apt to develop, and produce the picture of proliferating retinitis, perhaps with a new formation of vessels.
RECURRENT HEMORRHAGES INTO THE VITREOUS
Occasionally we meet with a young man who presents a peculiar clinical picture, the cause of which is unknown. At irregular intervals hemorrhages take place into the vitreous, often coincidentally with nosebleed. Sometimes he gives a history of having been engaged in violent exercise at the time the hemorrhage occurred, but the bleeding seems to be quite as likely to happen when no such explanation can be furnished. The young men may be in almost any kind of physical condition from hearty and robust, to weak and anemic, and may or may not be suffering from disease.
A striking feature in these cases is that the blood is absorbed rapidly, instead of slowly as in other forms of hemorrhage into the vitreous. The worst feature is that after a number of recurrences a proliferating retinitis, in the form of a growth of connective tissue in the vitreous, usually accompanied by many new vessels, is likely to develop and to impair the eye permanently.
PRERETINAL HEMORRHAGES
A red disk that is either round or has a horizontal upper border, and lies in front of a part of the retina, is a hemorrhage situated between the retina and the vitreous. In most cases it covers the macula, rarely the papilla.
FOREIGN BODIES AND PARASITES IN THE VITREOUS
When we see a part of the vitreous encroached upon from any direction we have to differentiate between a tumor of the retina or choroid, and a detachment of the retina. When an eye has been wounded a foreign body may be seen sometimes hanging in the vitreous, perhaps surrounded by a cloudy areola. Very rarely, at least in this country, we may see something that looks like a bluish white bladder in the vitreous, perhaps attached to the retina, which is recognized to be a cyst. If movements of its neck can be seen it may be diagnosed as a cysticercus, which is the probable diagnosis whenever a cyst is seen. Its appearance has been preceded by a detachment of the retina, the cause of which could not be recognized until the cyst broke through, and sooner or later the vitreous will become turbid and the eye be lost through an iridocyclitis.
In certain parts of the world filarie are said to form colonies in the vitreous that impair the vision but otherwise cause little trouble until they attack the ciliary body, or enter the anterior chamber, where they excite much pain and sometimes inflammation.
Key Takeaways
- Vitreous opacities can indicate serious eye conditions.
- Musce volitantes are harmless floating spots in the vitreous.
- Hyalitis is a hazy condition of the vitreous, often due to inflammation.
- Hemorrhages into the vitreous can be caused by various factors including trauma and systemic diseases.
Practical Tips
- Regular eye examinations are crucial for early detection of vitreous issues that could lead to vision loss.
- If you notice persistent floating spots in your field of vision, consult an ophthalmologist even if they do not affect your vision significantly.
- Maintain a healthy lifestyle and manage chronic conditions like diabetes and hypertension to prevent complications affecting the eyes.
Warnings & Risks
- Ignoring symptoms of eye pain or changes in vision can lead to permanent damage.
- Self-diagnosis and treatment for eye issues can be dangerous; always seek professional medical advice.
- Complications from untreated vitreous conditions, such as proliferating retinitis, can result in severe visual impairment.
Modern Application
While the techniques described in this chapter are historical, the importance of regular eye examinations and recognizing early signs of eye issues remains critical for modern survival preparedness. Understanding these conditions can help individuals seek timely medical attention, potentially preventing more serious complications.
Frequently Asked Questions
Q: What is musce volitantes?
Musce volitantes are harmless floating spots in the vitreous that move about in a person's field of vision. They are caused by microscopic particles or defects in the vitreous and do not indicate any serious disease.
Q: How can I differentiate between musce volitantes and true opacities?
If you notice spots that always appear in the same location when looking at a white surface, they are likely caused by fixed opacities. If the spots move around or disappear when you try to look directly at them, they are more likely musce volitantes.
Q: What causes hemorrhages into the vitreous?
Hemorrhages can be caused by trauma, spontaneous bleeding due to weakened blood vessels (like in arteriosclerosis), systemic diseases such as diabetes or hypertension, and other conditions like high myopia or retinitis.