CHAPTER 8

DEGENERATIVE CONDITIONS OF THE VITREOUS

J.J. WElTER and D.M. ALBERT

Outline

Asteroid hyalosis Clinical observations Morphologic characteristics and composition Comment

Cholesterosis bulbi (synchysis scintillans) Clinical observations Morphologic characteristics and composition Comment

Amyloidosis of the vitreous Clinical observations Morphologic characteristics and composition Comment

This chapter discusses three conditions, asteroid hyalosis, synchysis scintillans, and amyloidosis of the vitreous, commonly referred to as vitreous degenerations. The term vitreous degeneration is imprecise since it implies a primary process in the vitreous gel itself. The vitreous gel is composed of a liquid and a solid phase. The solid components of the vitreous constitute only 1 % of its weight and consist of collagen fibrils, peripheral cells, and small amounts of other proteins. The liquid phase (99%) is essentially water with the addition of hyaluronic acid, inorganic salts, ascorbic acid, and sugars. This type of configuration suggests that the major function of the vitreous is to modulate the passage of metabolites and other biochemical substances to and from adjacent tissues. Most likely, the only primary degeneration of the vitreous body itself is syneresis and vitreous detachment. Most vitreous

C. L. Schepens et al. (eds.), The Vitreous and Vitreoretinal Interface© Springer Science+Business Media New York 1987

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degenerations are secondary to primary retinal degenerations and are referred to as hyaloideoretinopathies. The vitreous gel may entrap material from surrounding tissues when they are diseased. Plasma pro­teins and inflammatory cells may enter the vitreous when the adjacent structures are inflamed.

The three conditions to be discussed in this chapter should be con­sidered secondary vitreous degenerations, in which the material accu­mulating in the vitreous is derived from elsewhere, although this has not been conclusively proven in the case of asteroid hyalosis.

Asteroid hyalosis

Clinical observations

Asteroid hyalosis is a well-recognized clinical entity that was first differentiated from synchysis scintillans by Benson in 1894 (I). Since the vitreous particles resembled "stars on a clear night", he termed the condition asteroid hyalitis. As there is no evidence of inflammation in most cases, the term asteroid hyalosis is the preferred name today. The names "scintillatio albescens" and "nivea" were later suggested by Wiegmann (2), and are still used in the European literature.

Asteroid hyalosis has the striking clinical appearance of glistening, yellowish white, spherical bodies suspended throughout the vitreous (fig. I). The asteroid bodies are variable in size and do not appear to be affected by gravity. This last observation is related to the otherwise normal-appearing vitreous gel that shows little or no evidence of lique­faction immediately surrounding these particles. Although the asteroid bodies can be so dense as to obscure the fundus (fig. 2), the patient is usually completely asymptomatic, with no decrease in visual acuity. Frequently, only a few asteroid bodies are present and may be easily overlooked fig. 3 (figs. 1-3, p. 130).

Asteroid hyalosis is unilateral in over 75% of cases (3). There appears to be no racial or sexual predilection (3). The average age at diagnosis is greater than 65 years, with an age range from 30 to 96 years. The con­dition has not been consistently associated with other ocular or sys­temic abnormalities. Earlier studies that reported an association be­tween diabetes mellitus and hypercholesterolemia (4-6) have been criti­cized for not being matched and controlled (3). A controlled study of patients with asteroid hyalosis did not show a significant elevation of the serum calcium (7). A biomicroscopic study of the vitreous gel in asteroid hyalosis (8) indicated that the gel was biomicroscopically nor-

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mal in 81 % of patients and showed moderate liquefaction in 19%. In only 12% was there a complete posterior vitreous detachment, a per­centage that is lower than expected for this age group. This reflects the absence of substantial vitreous liquefaction in the majority of patients with asteroid hyalosis.

Asteroid hyalosis seldom requires treatment, since it is usually asymptomatic and innocuous. The main difficulty is in visualizing the ocular fundus (figs. 1, 2), which is important because 27 to 70% of the patients with asteroid hyalosis also have diabetes mellitus (4-6). Fluor­escein angiography is of some benefit in evaluating fundus details because the asteroid bodies are "optically removed" during the angio­graphy (9). The asteroid bodies may interfere with photocoagulation in diabetic patients. Although photocoagulation can usually be performed in these patients, a rare case may require a vitrectomy before adequate photocoagulation can be carried out usefully. In very rare instances, dense concentrations of asteroid bodies in the visual axis may result in marked loss of vision (fig. 2)(10, 11). In such cases, pars plana closed vitrectomy may be indicated (12).

Morphologic characteristics and composition

Verhoeff described the histologic features of asteroid hyalosis in 1921 (13). He noted that the asteroid bodies were roughly spherical, ranged in size between 0.01 and 0.1 mm, and were calcium soaps admixed with insoluble lipid compounds. The histologic findings in asteroid hyalosis are fairly typical (fig. 4). The asteroid bodies appear weakly basophilic with hematoxylin-eosin stains. They stain positively with lipid stains (oil red 0, Sudan black B, Scharlach R, Nile blue sulfate), but resist the usual fat solvents. They stain positively for acid mucopolysaccharides (alcian blue, colloidal iron), and this reaction is unaffected by hyaluronidase. When viewed under polarized light, the asteroid bodies contain birefringent areas embedded in a matrix of nonbirefringent material that is intimately associated with vitreous fibrils, suggesting that the asteroid bodies may arise from degeneration of the vitreous fibrils (14). Rodman et al. (14) confirmed the presence of calcium and also concluded that asteroid bodies were calcium soaps. Using electron-probe analysis, March et al. (15) detected calcium and phosphate as major elements. They suggested that calcium was present as an apatite (a calcium phosphate complex similar to that found in bone) rather than as a soap or a calcium salt of long-chain fatty acids.

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Fig. 5. - Left, scanning electron micrograph of two asteroid bodies connected by vitreous strand (x 5(0). Center, same asteroid bodies viewed by energy dispersive X-ray mapping denotes calcium concentrated within asteroid opacities (x 500). Right, X-ray spectrograph of asteroid bodies demonstrates sharp peaks for phosphorus (P) and calcium (C). (From ref. 8. Courtesy of Dr. K. R. Kenyon).

They also found a small, electron-dense asteroid body that contained no evidence of lipids.

Three X-ray absorption studies confirmed the presence of calcium and phosphorus (8, 16, 17) (fig. 5). Electron-diffraction structural anal­ysis showed that calcium hydroxyapatite, and possibly other forms of calcium phosphate crystals, were present in focal densities. They also noted multiple parallel lamellae of complex lipids with a 6 nm period­icity (fig. 6). The diffuse birefringent pattern noted when viewing aste­roid bodies with polarized light is probably related to this lamellar lipid pattern, typical of liquid crystalline phases of lipids in water; it has been proposed that the asteroid bodies are not true crystals but phos­pholipid liquid crystals (17). The term liquid crystal was chosen to des­cribe their intermediate state between a true crystal and a true liquid.

Fig. 6. - Left, transmission electron micrograph (TEM) of free asteroid body demon­strates irregular calcific composition (x 9000). Center, high-resolution TEM of asteroid body resolves multiple parallel lamellae of complex lipid with approximately 60 A 0 repeat periodicity (x 70 000). Right, electron micrograph of spherule also shows membranous lamellar pattern characteristic of complex lipids (x 43 5(0). (From ref. 8. Courtesy of Dr. K. R. Kenyon).

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Scanning (fig. 5) and transmission (fig. 7) electron microscopy of asteroid hyalosis shows the asteroid bodies to be enmeshed within strands of vitreous collagen (8). The surface of individual asteroid bod­ies appears porous (fig. 5). No associated cellular or extracellular com­ponents could be discerned with scanning electron microscopy (8).

Rodman et al. (14) divided asteroid hyalosis into two types. The usual cases, Type I, showed asteroid bodies in a normal vitreous. Other

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cases, Type 2, showed larger asteroid bodies, often embedded in dense vitreous membranes and exciting a granulomatous reaction. These larg­er asteroid bodies occurred in diseased eyes, especially in the presence of uveitis. The finding of asteroid bodies associated with macrophages has been verified by ourselves (fig. 8) and others (8, 16). No histochem­ical differences were found between these two types (14).

Fig. 8. - Electron micrograph of a vitrectomy specimen from a patient with asteroid hyalosis showing a macrophage (M) phagocytosing cholesterol-like material (arrows).

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Comment

As part of this review, the findings in 30 patients with asteroid hya­losis were studied. The average age was 68 years, with a range from 48 to 88 years. Seventeen were women and 13 were men (most likely reflecting the greater longevity of women and not a sex difference). All patients were white (reflecting the referral practice from which the patients were drawn). Ten of the patients had diabetic retinopathy and five had had a vitreous hemorrhage (including three of the ten diabetic patients). An additional patient had a history of uveitis, and one had had a central retinal vein occlusion. Fifteen patients were hyperopic, 12 emmetropic, and only three myopic. Compared with controls, this ten­dency toward hyperopia with a decreased prevalence of myopia was significant (p<O.OI). Biomicroscopic examination showed the asteroid bodies to be unilateral in 21 patients. Among the nine bilateral cases, four showed bilateral asteroid bodies with marked asymmetry, with one eye exhibiting no more than four definite asteroid bodies (fig. 3). One patient had bilateral asteroid bodies so dense that vision was in the counting finger range and fundus details were markedly obscured (fig. 2). Similar to previous findings (8), the vitreous gel showed mod­erate liquefaction in only eight patients and was essentially normal in 22 (73%) patients. There was no posterior vitreous detachment in 21 patients (figs. 1-3). Three patients had a complete posterior vitreous detachment in the eye without asteroid bodies but not in the eye with asteroid bodies, and two patients had bilateral complete posterior detachments. Four patients had bilateral partial vitreous detachments. Compared with an age-matched control series, posterior vitreous de­tachment and liquefaction was significantly (p<O.OI) less common in eyes with asteroid hyalosis than in controls. Two patients were noted to have a marked increase in asteroid bodies within a six-month period after a vitreous hemorrhage.

Asteroid hyalosis was infrequently associated with retinal detach­ment, most likely reflecting the low incidence of posterior vitreous detachment and myopia in asteroid hyalosis. Two patients were refer­red with retinal detachments following vitrectomies for dense asteroid hyalosis. This could be indicative of an even stronger than normal vitreoretinal adhesion.

What is the significance of these studies? Asteroid hyalosis is asso­ciated with a vitreous gel in which liquefaction and posterior vitreous detachment are less prevalent. This probably explains the negative

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aSSOcIatIOn between asteroid hyalosis and both myopia and retinal detachment (p<O.OI). Furthermore, one could speculate that the pre­sence of a more solid gel serves as a matrix (nucleation site) upon which liquid crystals (17) can grow. In aging collagen or elastin, calcium binding to free polar groups on the fibers is thought to form nucleation sites for mineralization (18). The complex liquid and calcium-phospho­rus composition of asteroid bodies suggests that these components are derived from elsewhere since the relatively acellular vitreous is unlikely to have sufficient intrinsic phospholipid for these bodies (16). Brief inflammation, or hemorrhage or leakage from adjacent vessels, may be the source of these calcium-phospholipid complexes (16). The rapid increase in the formation of asteroid bodies following vitreous hemor­rhage, as noted above, lends support to this idea. Experimental asteroid bodies can be induced by means of a combination of abnormal blood flow and hypercholesterolemia (19). Local factors such as changes in pH or calcium ion concentrations (7) could also contribute to the for­mation of asteroid bodies. Experimental evidence suggests that depoly­merization of hyaluronic acid might play an early role in asteroid body formation (20).

Cholesterosis bulbi (synchysis scintillans)

Clinical observations

A condition sometimes confused with asteroid hyalosis is synchysis scintillans or cholesterosis bulbi. The term synchysis is derived from the Greek word meaning "mixed together". In 1846 Sichel first de­scribed shining crystals in the vitreous cavity after a cataract remov­al (21). The crystals floated freely in the vitreous cavity when the eye moved, and settled down when the eye was at rest. He termed this condition" syncMsis etincelant". Numerous other reports of synchysis scintillans appeared in the late 19th-century literature and usually described intraocular, moving, shining crystals found in badly trauma­tized or diseased eyes in which the lens was missing. In 20th-century ophthalmic literature, synchysis scintillans gradually assumed a definite clinical identity. Usually it appeared in the literature as part of the differential diagnosis of whitish bodies in the vitreous and was con­trasted with asteroid hyalosis. The small white crystals seen floating freely in the vitreous cavity with ocular movement (fig. 9) are not thought to be associated with the vitreous, which is believed to be

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liquefied in this condition. In contrast, the asteroid bodies are intimate­ly associated with the vitreous gel and are constrained in their move­ment by the vitreous fibrils. The individual synchysis scintillans crys­tals have a flat, angular, cyrstalline appearance in contrast to the round, white asteroid spheres. Furthermore, whereas asteroid bodies were found unilaterally in elderly patients, synchysis scintillans was said to "occur more often in patients under 35 years of age and to be usually bilateral" (22). Microscopic and compositional studies further differen­tiated these two entities. Whereas the asteroid bodies are composed of a complex of lipid-calcium-phosphorus, the synchysis scintillans crys­tals are cholesterol crystals. Thus, the alternative and more appropriate term for synchysis scintillans is cholesterosis bulbi.

Despite cholesterosis bulbi being entrenched in the ophthalmic liter­ature as a well-defined clinical entity, several authors have raised doubts (23,24). Jaffe (23), in a review of patients in Miami, was unable to identify a single case. Wand et al. (24), in a review of in-patient records at the Massachusetts Eye and Ear Infirmary (ten years) and the in-patient and out-patient records at the Children's Hospital Medical Center (eight years), found no cases of diagnosed cholesterosis bulbi. The latter study was prompted by a case report of cholesterolosis of the anterior chamber, which was thought to be rare, unlike synchysis scin­tillans, which was thought to occur fairly commonly (25). The recent literature shows no reports of anterior chamber cholesterol crystals in a healthy eye; most cases were in blind eyes that had suffered severe ocular trauma or disease. The age range of the patients was 11 to 83 years. The most frequent antecedent ocular insult was trauma severe enough to result in cataract, lens subluxation, retinal detachment, and vitreous hemorrhage. Other causes were mature or hypermature cata­ract, chronic uveitis, long-standing retinal detachment, and vascular disorders. These authors suggest that cholesterol crystals in the anterior chamber, rather than being rare, are the usual manifestation of the so­called synchysis scintillans clinical entity (24, 25). They feel that the term synchysis scintillans, which implies that the vitreous crystals are visible, is inappropriate since these eyes are usually cataractous. The crystals would be visible only if the lens were missing, and a cataract extraction would not be performed on such obviously diseased eyes. The authors recommend replacing the term synchysis scintillans with cholesterosis bulbi, since the latter encompasses the presence of choles­terol crystals in all parts of the eye.

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Morphologic characteristics and composition

Although cholesterosis bulbi as a clinical entity is quite rare, the occurrence of cholesterol crystals in a degenerated eye is· not rare. In routine paraffin-embedded sections of organized vitreous, the charac­teristic histopathologic picture shows numerous slitlike spaces devoid of content because the cholesterol esters dissolve in the processing. Using frozen sections, the birefringent nature of the cholesterol crystals can be demonstrated with polarized light. It is not unusual to find a low-grade inflammatory response characterized primarily by foreign­body giant cells associated with the cholesterol crystals.

The exact etiology of the cholesterol crystals in cholesterosis bulbi is uncertain. Most likely the cholesterol is derived from plasma leaking through blood vessel walls or results from the breakdown of red blood cells (26). The fact that most cases of cholesterosis bulbi are associated with vitreous hemorrhage or chronic inflammation lends support to the idea that these crystals are a blood product.

Comment

The older concept and terminology of synchysis scintillans are inap­propriate because the vitreous need not be liquefied for the crystals to appear. The crystals are not limited to the vitreous cavity, and the vitreous crystals are usually not visible because of opacities in the media. Cholesterosis bulbi is the more appropriate term since it not only describes more accurately the composition of the opacities but also encompasses the presence of cholesterol crystals in other parts of the eye. The authors have only seen one clinical case of synchysis scin­tillans (fig. 9), although cases of cholesterol crystals in the anterior chamber have been seen. As noted previously (24), the anterior cham­ber crystals are the usual manifestation of cholesterosis bulbi. The authors have seen many clinical cases of cholesterol crystals in the subretinal space in Coats' disease, long-standing retinal detachments, and subretinal hemorrhage. The entity of cholesterosis bulbi is basically a pathologic fmding in severely traumatized and diseased eyes and is relatively rare as a clinical entity.

Amyloidosis of the vitreous

Clinical observations

Amyloidosis is a disease caused by localized or generalized deposi­tion of an abnormal protein in the body. The pathogenesis of this dis-

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ease complex remains obscure. One of several classification schemes for amyloidosis divides cases into amyloidosis associated with an un­derlying disease, familial amyloidosis, and idiopathic amyloidosis (27, 28). Familial amyloidosis is always autosomal dominant. Although sys­temic amyloidosis has been recognized as a clinical entity since the early 19th century (29), vitreous involvement was not reported until 1953 (30). Opacification of the vitreous caused by amyloid is an un­common and often misdiagnosed condition that causes progressive visual loss. The process is usually associated with primary familial sys­temic amyloidosis. Ocular involvement was found in 8 % of cases of familial amyloidosis but the incidence may be higher (31). Only five apparently sporadic cases of amyloidosis of the vitreous have been reported (32, 33).

Systemic manifestations of primary familial amyloidosis are general­ized weakness, weight loss, progressive peripheral neuropathy, and dis­turbances in the gastrointestinal, cardiovascular, and endocrine sys­tems. Symptoms usually appear after the second decade, and the dis­ease runs a course of approximately 20 years. The diagnosis of systemic amyloidosis is usually confirmed by biopsy; skin, gingiva, rectum, liv­er, kidney, spleen, respiratory tract, and sternal puncture have all been used. Ease of access and hemostasis have made the gingiva and rectum the two main sites. The secondary type of amyloidosis is associated with chronic debilitating diseases, such as infections or non-infectious chronic inflammation, neoplasm, metabolic disorders, and dysprotei­nemias. Leprosy, osteomyelitis, rheumatoid arthritis, and multiple myeloma are specific examples of diseases associated with secondary amyloidosis.

Ocular involvement in amyloidosis has been extensively re­viewed (34). Involvement of the cornea, conjunctiva, vitreous, retina, sclera, episclera, optic nerve, eyelid, orbit, lacrimal gland, and extra­ocular muscles have been well documented (33). This involvement may be associated with diplopia, sudden or progressive loss of vision, pho­tophobia, blepharospasm, anisocoria, external ophthalmoplegia, bila­teral exophthalmos, and a sluggish pupillary reflex. Lattice corneal dys­trophy, one of the inherited corneal dystrophies, is considered by some to be a primary, localized amyloidosis of the cornea.

Vitreous involvement may be the first clinical manifestation of pri­mary familial amyloidosis, occurring long before other organs of the body are affected. When amyloidosis affects the vitreous, it usually involves both eyes, one eye being affected more severely than the oth-

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er (34). Although the pathogenesis of vitreous amyloid is not entirely clear, the most likely explanation appears to be extension of amyloid from the adventitia of the retinal vessels into the vitreous through dis­continuities in the internal limiting membrane (35). The amyloid opa­cities first begin around retinal blood vessels, particularly arterioles, and simulate the appearance of a "cottonwool" spot (36). A fluorescein angiographic study in amyloidosis of the vitreous has shown leakage from retinal capillaries (37). Equatorial blot hemorrhages as well as white sheathed vessels have been seen. Another study demonstrated no retinal vascular leakage of fluorescein from the vast number of areas in which amyloid was being deposited (38). These authors concluded that although microvascular injury may occur in primary systemic amyloi­dosis, the major deposition of amyloid proceeds independently of these lesions from vessels that are clinically and angiographically nor­mal (38). The frequent finding of sheathed vessels and the report of retinal neovascularization (38) suggest that the amyloid deposits may occlude retinal vessels. This has been verified in an electron microscop­ic study (39).

The density of the amyloid material increases progressively, eventu­ally covering a segment of a retinal vessel and extending into the vitreous. The vitreous involvement begins with the cortical layer and slowly spreads into the central vitreous body. There is a tendency for the vitreous to be affected in a posterior to anterior direction. At first the vitreous opacities are not well defined and may form granular opa­cities with wispy fringes. As the vitreous opacities enlarge and aggre­gate, they form sheetlike vitreous veils that eventually take on a "glass wool" appearance (fig. 10). If the posterior vitreous detaches, the opa­cities may be displaced into the visual axis, causing a reduction in vision (36). This may account for a sudden loss of vision in some patients whose amyloid opacities are not very dense.

Medical treatment of primary familial amyloidosis is unsatisfactory. Surgical removal of the opacified vitreous is the accepted method of treatment. The first successful surgical treatment of amyloidosis of the vitreous, described by Kasner et al. in 1968 (40), used an open-sky vitrectomy technique. Pars plana vitrectomy is the accepted technique today (12, 37, 41, 42), despite possible recurrence of the amyloid opa­cities after successful vitrectomy (42). Such recurrence was attributed to failure to remove a small amount of clear vitreous behind the lens, which later became infiltrated with amyloid.

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Morphologic characteristics and composition

Histologic examination of vitreous amyloid deposits show a fibrillar pattern of fine and coarse meshworks that stain positively with periodic acid-Schiff and congo red, and metachromatically with crystal violet (fig. 11). Under polarized light, hematoxylin and eosin sections show birefringency, and congo red stained sections show a green dichroism. Electron microscopic (34) and X-ray (43) diffraction studies have shown amyloid to be composed of unique fibrillar components having an antiparallel B-pleated sheet configuration, which is responsible for the optical and staining properties of amyloid. Aggregates of amyloid fibrils often appear to have a wavy, haphazard arrangement in contrast with the straight, orderly appearance of collagen. Immunocytochemical studies have shown the major amyloid constituent to be a protein resembling prealbumin (44).

Comment

Early discovery of amyloid deposits in the retina and vitreous body help establish a correct diagnosis of amyloidosis in an otherwise heal­thy patient. Since this disorder is inherited as a dominant trait, the family of an affected person should be examined to determine whether other members have the condition. The vitreous opacities in amyloi­dosis may be confused with those resulting from more common causes, such as hemorrhage or inflammation. Although there is no proven medical treatment for primary familial amyloidosis, closed vitrectomy appears to be beneficial when vision is markedly decreased secondary to dense vitreous opacities. As noted above, recurrent vitreous opaci­ties may occui' in residual vitreous. The prognosis is favorable if there is a posterior vitreous detachment. If the posterior vitreous is not detached, there is a high risk of producing retinal tears and hemor­rhages or leaving behind amyloid opacities that are firmly attached to the retina.

REFERENCES

(1) BENSON, A.H. - Diseases of the vitreous. Trans. Ophthalmol Soc. UK, 1894, 14, 101-104.

(2) WIEGMANN, E. - Ein Beitrag zur Genese und zum Bilde der Synchysis scintillans. Klin. Montasbl. Augenheilkd., 1918, 61, 82-88.

(3) LUXENBERG, M., SIME, D. - Relationship of asteroid hyalosis to diabetes mellitus and plasma lipid levels. Am. l. Ophthalmol., 1969, 67, 406-413.

(4) SMITH, J.L. - Asteroid hyalitis: incidence of diabetes mellitus and hypercholestero­lemia. lAMA, 1958, 168, 891-893.

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(5) BARD, L.A. - Asteroid hyalitis: relationship to diabetes mellitus and hypercholeste­rolemia. Am. J. Ophthalmol., 1964, 58, 239-242.

(6) SMITH, J.L. - Asteroid hyalitis and diabetes mellitus. Trans. Am. Acad. Ophthalmol. Otolaryngol., 1965, 69, 269-277.

(7) JERVEY, E.D., ANDERSON, W.B. - Asteroid hyalitis: a study of serum calcium levels in affected patients. South. Med. J., 1965, 58, 191-194.

(8) TOPILOW, H.W., KENYON, K.R., TAKAHASHI, M., FREEMAN, H.M., TOLEN­TINO, F.I., HANNlNEN, L.A. - Asteroid hyalosis: biomicroscopy, ultrastructure, and composition. Arch. Ophthalmol., 1982, 100, 964-968.

(9) HAMPTON, G. R., NELSON, P. T., HAY, P. B. - Viewing through the asteroids. Ophthalmology, 1981, 88, 669-672.

(10) CIBIS, P. - Vitreoretinal pathology and surgery in retinal detachment. St. Louis: C. V. Mosby, 1965, 193.

(11) YAMADA, K., SHIMIZU, H. - Asteroid hyalosis causing visual disturbance. Jpn. J. C/in. Ophthalmol., 1976, 30, 787.

(12) TOLENTINO, F.I., SCHEPENS, c.L., FREEMAN, H.M. - Vitreoretinal disorders: diagnosis and management. Philadelphia: W.B. Saunders, 1976,230.

(13) VERHOEFF, F. H. - Microscopic findings in a case of asteroid hyalitis. Am. J. Oph­thalmol., 1921, 4, 155-160.

(14) RODMAN, H.F., JOHNSON, F.B., ZIMMERMAN, L.E. - New histopathological and histochemical observations concerning asteroid hyalitis. Arch. Ophthalmol., 1961, 66, 552-563.

(15) MARCH, W.F., SHOCH, D., O'GRADY, R. - Composition of asteroid bodies. Invest. Ophthalmol. Vis. Sci., 1974, 13,701-707.

(16) STREETEN, B. W. - Vitreous asteroid bodies: ultrastructural characteristics and composition. Arch. Ophthalmol., 1982, 100, 969-975.

(17) MILLER, H., MILLER, B., RABINOWITZ, H., ZONIS, S., NIR, I. - Asteroid bod­ies. An ultrastructural study. Invest. Ophthalmol Vis. Sci., 1983, 24, 133-136.

(18) YU, S. Y., BLUMENTHAL, H. T. - The calcification of elastic tissue. In: Wagner B.M., Smith D.E. (eds.), The connective tissue. Baltimore: Williams & Williams, 1967, 17-49.

(19) ZAUBERMAN, H., LIONI, N. - Experimental vascular occlusion in hypercholeste­rolemic rabbits. Invest. Ophthalmol. Vis. Sci., 1981, 21, 248-255.

(20) LAMBA, P.A., SHUKLA, K.N. - Experimental asteroid hyalopathy. Br. J. Ophthal­mol., 1971, 55, 279-283.

(21) SICHEL, J. - Note complementaire sur Ie synchesis etincellant. Ann. Oculistique, 1846, 15, 248.

(22) HOGAN, M.J., ZIMMERMAN, L.E. (eds.). - Ophthalmic Pathology, 2nd ed. Phi­ladelphia: W.B. Saunders, 1962, 650-654.

(23) JAFFE, N.S. - The vitreous in clinical ophthalmology. St. Louis: C.V. Mosby, 1969, 223-226.

(24) WAND, M., SMITH, T.R., COGAN, D.G. - Cholesterosis bulbi: the ocular abnor­mality known as synchysis scintillans. Am. J. Ophthalmol., 1975,80, 177-183.

(25) WAND, M., GORN, R.A. - Cholesterolosis of the anterior chamber. Am. J. Oph­thalmol., 1974, 78, 143-144.

(26) ANDREWS, J.S., LYNN, c., SCOBEY, J.W., ELLIOTT, J.W. - Cholesterosis bulbi: case report with modern chemical identification of the ubiquitous crystals. Br. J. Oph­thalmol., 1973, 57, 838-844.

(27) GLENNER, G.G. - Amyloid deposits and amyloidosis. Part 1. N. Engl. J. Med., 1980, 302, 1283-1292.

(28) GLENNER, G. G. - Amyloid deposits and amyloidosis. Part II. N. Engl. J. Med., 1980,302, 1333-1343.

(29) VIRCHOW, R. - Cellular pathology as based upon physiological and pathological histology. Philadelphia: J. B. Lippincott, 1963, 554.

(30) KANTARJIAN, A.D., DEJONG, R.N. - Familial primary amyloidosis with nervous system involvement. Neurology, 1953, 3, 399-409.

(31) RUKAVINA, J.G., BLOCK, W.D., JACKSON, C.E. et al. - Primary systemic amy­loidosis: a review and an experimental, genetic and clinical study of 29 cases with particular emphasis on the familial form. Medicine, 1956, 35, 239-334.

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(32) FERRY, A. P., LIEBERMAN, T. W. - Bilateral amyloidosis of the vitreous body. Report of a case without systemic or familial involvement. Arch. Ophthalmol., 1976, 94, 982-991.

(33) SCHWARTZ, M.F., GREEN, W.R, MICHELS, R.G. et al. - An unusual case of ocular involvement in primary systemic nonfamilial amyloidosis. Ophthalmology, 1982, 89, 394-401.

(34) HITCHINGS, R.A., TRIPATHI, R.C. - Vitreous opacities in primary amyloid dis­ease: a clinical, histochemical, and ultrastructural report. Br. J. Ophthalmol., 1976,60, 41-54.

(35) WANG, V.G., McFARLIN, D.E. - Primary familial amyloidosis. Arch. Ophthalmol., 1967, 78, 208-213.

(36) KAUFMAN, H.E., THOMAS, L.B. - Vitreous opacities diagnostic of familial pri­mary amyloidosis. N. Engl. J. Med., 1959, 261, 1267-1271.

(37) TSUKAHARA, S., MATSUO, T. - Fluorographical findings in familial primary amyloidosis. Ophthalmologica, 1978, l76, 301-307.

(38) SAVAGE, D.J., MANGO, c.A., STREETEN, B.W. - Amyloidosis of the vitreous. Fluorescein angiographic findings and association with neovascularization. Arch. Oph­thalmol., 1982, 100, 1776-1779.

(39) INOMATA, H., OKAYAMA, M., OSHIMA, K. - Familial primary amyloidosis. Jpn. J. Ophthalmol., 1976,20, 51-62.

(40) KASNER, 0., MILLER, G.R, TAYLOR, W.H., SEVER, RJ., NORTON, E.W.D.­Surgical treatment of amyloidosis of the vitreous. Trans. Am. Acad. Ophthalmol. Oto­laryngol., 1968, 72, 410-418.

(41) MATSUI, M., TASHIRO, T., ASAI, Y. - A case of bilateral vitreous amyloidosis which was successfully treated with vitreous surgery. Acta Soc. Ophthalmol. Jpn., 1976, 80, 142-146.

(42) IRVINE, A.R., CHAR, D.H. - Recurrent amyloid involvement in the vitreous body after vitrectomy. Am. J. Ophthalmol., 1976, 82, 705-708.

(43) EANES, E.D., GLENNER, G.G. - X-ray diffraction studies of amyloid filaments. J. Histochem. Cytochem., 1968, 16, 673-677.

(44) DOFT, B.H., RUBINOW, A., COHEN, A.S. - Immunocytochemical demonstration of prealbumin in the vitreous in heredofamilial amyloidosis. Am. J. Ophthalmol., 1984, 97, 296-300.

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Fig. I. - Slitlarnp photograph of asteroid hyalosis. The vitreous cortex is attached to the retina. The asteroid bodies are moderately dense. [Top left]

Fig. 2. - Slitlamp photograph of asteroid hyaiosis. The vitreous cortex is attached to the retina. The asteroid bodies are so dense as to prevent a fundus view. [Bottom]

Fig. 3. - Slitiamp photograph of asteroid hyalosis. The vitreous cortex is attached to the retina. Only a minimal number of asteroid bodies are present and could easily be over­looked. [Top right]

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,

Fig. 4. - Asteroid hyalosis from a vitrectomy specimen (hematoxylin and eosin). Left, low-power view (x 12); Right, higher-power view (x 80).

Fig. 9. - SlitIarnp photograph of cholesterol crystals in the vitreous cavity of a patient with a history of trauma and long-standing intraocular hemorrhage.

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Fig. 10. - Slitlamp photograph of amyloid in the vitreous. Fig. 11. - Photomicrograph of vitrectomy specimen from patient with amyloid. (Congo

red, x 12).