Brit. J. Ophthal. (1975) 59, 413 Br J Ophthalmol: first published as 10.1136/bjo.59.8.413 on 1 August 1975. Downloaded from

Drusen of the A retrospective study in cadaver eyes

ALAN H. FRIEDMAN, SAMUEL GARTNER, AND SATISH S. MODI From the Department of , Albert Einstein College of Medicine, Montefiore Hospital and Medical Center, New rork

Since Muller (I 858) first gave a histopathological Material and methods description and Liebreich first a clinical (i868) gave The eyes of 737 patients who came to necropsy during a description, of the optic disc have excited the consecutive period at Montefiore Hospital were used. interest of the ophthalmoloist. Although the litera- These eyes were obtained whenever permission was granted ture on is Vast,,the aetiology remains for a full necropsy. Only a small number of these patients a mystery. had received an ophthalmological examination before Lorentzen (I966), in a clinical study of 3200 death. Both eyes were removed and fixed in IO per cent subjects, reported an incidence of 3-4 per thousand. neutral buffered formalin, processed in either celloidin or In this paper we report on the incidence and histo- paraffin, and sectioned at I5 pm (celloidin) or 9 or IO pm pathological features of optic disc drusen in a retro- (paraffin). As a matter of routine 20 or more sections were spective necropsy survey. taken at random through the and the macular area was studied unless a specific pathological process copyright. was present that warranted special study.

Address for reprints: Dr A. H. Friedman, Department of Ophthalmo- logy, Albert Einstein College of Medicine/Montefiore Hospital and Results Medical Center, Ill East 210th Street, Bronx, New York 10467 There were I5 cases of drusen of the optic disc This research was supported in part by the National Eye Institute Grant Number R01-EY00613-04 and the Seeing Eye, Morristown, among the eyes of the 737 patients whose eyes were New Jersey 07960 examined histopathologically (Table I). This figure represents an incidence of 20 4 cases per IOOO http://bjo.bmj.com/ Table I Drusen of the optic disc

Partial Cellular Solitary Elevated optic Cytoid Iron infiltrate Case no. Age Sex Laterality or multiple Size Location disc atrophy bodies Haemorrhage Calcification deposition about drusen on September 25, 2021 by guest. Protected 51 M Both eyes Multiple L Superficial Partial + - + Absent + and deep 2 63 F Left eye Multiple S Superficial Full + Not - studied 3 55 M Left eye Solitary S Deep - + Not studied 4 62 M Right eye Multiple S Superficial - -- + Not - studied _v+ 5 63 F Right eye Solitary S Deep + Not - studied 6 47 M Right eye Multiple L Superficial r+. + Absent + 7 46 M Right eye Solitary S Deep _-+ Not studied 8 43 M Left eye Solitary S Deep - I- Absent 9 49 F Right eye Multiple M Superficial Partial + + Not studied 10 75 M Right eye Multiple S Deep - - + Not - studied 11 62 M Both eyes Multiple L Superficial Full - -+ Present 12 47 F Left eye Solitary S Superficial + Present 13 4Q p Right eye Solitary S Deep + Absent 14 50 M Right eye Solitary S Deep - + Present 15 76 M Left eye Multiple L Superficial Full - + Present ±

Size: L=Large greater than one-half disc diameter M=Medium one-quarter to one-half disc diameter S=Small less than one-quarter disc diameter 414 British Journal of Ophthalmology Br J Ophthalmol: first published as 10.1136/bjo.59.8.413 on 1 August 1975. Downloaded from

patients. Only two patients in this study manifested (Table I). The average age of this series of patients bilateral drusen. Other ocular findings included was 55-9 years. one case each of pigmentosa, open-angle The large number of optic disc drusen studied , central retinal artery occlusion, inactive afforded us an opportunity to observe many of the peripheral chorio-retinitis, and histopathological features. The drusen varied enor- copyright.

FIG. I Case I, multiple drusen of varying sizes lying at different levels ofoptic nerve head. Haematoxylin and eosin. x IOO http://bjo.bmj.com/ on September 25, 2021 by guest. Protected

FIG. 2 Case 3, small solitary drusen lying anterior to lamina cribrosa. Haematoxylin and eosin. x I25 Drusen of the optic disc 415 Br J Ophthalmol: first published as 10.1136/bjo.59.8.413 on 1 August 1975. Downloaded from

mously in size and number. Six of the cases displayed material was also noted in the outer plexiform layer. a multitude of drusen (Fig. i). The drusen ranged in In every instance the optic disc drusen were calci- size from about 50 ,m (Fig. 2) to one that measured fied. In eight cases the drusen were studied for iron 750 pum across and occupied more than one-halfofthe constant using Perls' stain and four stained intensely disc. The drusen could be seen at all levels of the positive. This finding has not been previously reported prelaminar optic nerve although the smaller ones as far as we could find. tended to be closer to the lamina cribrosa (Fig. 2). A superficial optic nerve haemorrhage was observed in two cases (Fig. 3). In one case both eyes showed Discussion juxtapapillary retinal scarring with deposition of The 20 or so optic nerve sections studied in each eye haemosiderin (Fig. 4a). The proximity of drusen to represented only a small fraction, less than 20 per adjacent blood vessels was noted in the latter case cent of the total optic nerve. It is conceivable that (Fig. 4b). if each optic nerve had been serially sectioned in its The effect of drusen on the adjacent optic nerve entirety a much higher incidence of optic disc drusen fibres was observed in several cases. In four cases the would have been encountered. Comparing optic nerves showed partial atrophy of the peri- Lorentzen's incidence of 3-4 cases per thousand to our axial fibres (Fig. 5) while one case showed cytoid incidence of 20 4 cases per thousand suggests that bodies adjacent to the nerve head (Fig. 6). In several one in six (I 7 per cent) optic disc drusen is clinically cases drusen were observed to compress adjacent visible. Many of the remaining 83 per cent disc optic nerve fibres (Fig. 7). A cellular reaction was drusen which are not diagnosed clinically may re- noted about drusen in several instances (Fig. 8). present those that are minute or lie deep in the nerve As previously noted the drusen produced changes head nearer to the lamina cribrosa. In our series, nine in the adjacent . In one case (Fig. 4a) bilateral minute or deeply lying drusen represented 6o per cent

jutxtapapillary retinal scarring with haemosiderin ofall cases and may partially explain the disparity be- copyright. deposition could be seen, and in a second case (Fig. 9) tween the clinical and histopathological studies. the retina on the same side of the disc as the drusen Drusen were thought for a long time to be displayed degeneration of the outer nuclear, photo- innocuous, however, studies have shown that they receptor, and pigment epithelial layers. Exudative may be associated with visual field defects in many http://bjo.bmj.com/ on September 25, 2021 by guest. Protected

FIG. 3 Case 9, superficial haemorrhage (arrow) in retina adjacent to disc. Note peripapillary retinal scarring. Haematoxylin and eosin. x 50 4I6 British Journal of Ophthalmology Br J Ophthalmol: first published as 10.1136/bjo.59.8.413 on 1 August 1975. Downloaded from copyright.

FIG. 4a Case i i, (right eye). Peripapillary retinal scarring (arrows). Haematoxylin and eosin. x 125 http://bjo.bmj.com/ on September 25, 2021 by guest. Protected

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FIG. 4b Case 6, a small vessel (arrow) running axially in optic nerve between two drusen. Haematoxylin and eosin. x 3I5 instances (Rucker, I 944). In our series four eyes drusen excited a microglial reaction in three cases. manifested partial optic atrophy while a fifth eye Five eyes demonstrated disc oedema with partial or showed cytoid bodies involving the nerve head. The full elevation ofthe nerve head. The aetiology ofthese Drusen of the optic disc 417 Br J Ophthalmol: first published as 10.1136/bjo.59.8.413 on 1 August 1975. Downloaded from copyright. http://bjo.bmj.com/ on September 25, 2021 by guest. Protected

FIG. 5 Case I5, longitudinal view of optic nerve showing drusen anterior with periaxial optic atrophy. Haematoxylin and eosin. x 50 three processes may be due to the mechanical strating that there was an increase in the size of the compression of optic nerve fibres or interference with drusen. their blood supply by the gradually enlarging disc The association between drusen of the optic disc drusen. Krill, Klien, and Archer (I973) reported a and retinal haemorrhages has received extensive case in which bilateral drusen of the disc were attention in recent years (Sanders, Gay, and Newman, diagnosed when the patient was aged 3, photographed 197I; Brodrick, 1973; Henkind, Alterman, and when aged 8, and again when aged I 5, clearly demon- Wise, I972). On the basis of ophthalmoscopic 418 British Journal of Ophthalmology Br J Ophthalmol: first published as 10.1136/bjo.59.8.413 on 1 August 1975. Downloaded from copyright.

FIG. 6 Case I2, cytoid bodies in juxtapap zry tissues in case displaying a solitary, small drusen (not seen in this section). Axon. x 3I5 http://bjo.bmj.com/ on September 25, 2021 by guest. Protected

FIG. 7 Case i, compression ofnerve fibres (arrow) between drusen. Haematoxylin and eosin. X 125 Drusen of the optic disc 419 Br J Ophthalmol: first published as 10.1136/bjo.59.8.413 on 1 August 1975. Downloaded from

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FIG. 8 Case I I (left eye). Cellular reaction about drusen. Haematoxylin and eosin. x I25 http://bjo.bmj.com/ on September 25, 2021 by guest. Protected

FIG. 9 Case I I (left eye). Retina adjacent to disc on temporal side shows disturbance in retinal pigment epithelium, outer nuclear, and photoreceptor layers. Exudative material in outer plexiform layer (arrow). Haematoxylin and eosin. x 258 420 British Journal of Ophthalmology Br J Ophthalmol: first published as 10.1136/bjo.59.8.413 on 1 August 1975. Downloaded from

observations, four types of haemorrhages have been degradation product of albumin, related to hyalin, described: and had a tendency to take up calcium. Seitz and Kersting (I962) thought drusen to be of glial origin, i. Splinter haemorrhages in the nerve fibres of the representing the end product of nerve fibre degenera- disc tion, a theory first proposed by Fuchs (I927) and 2. Haemorrhages of the nerve head extending into later supported by the work of Wolter and Falls the vitreous (Gaynes and Towle, I967) (I962). Muller (I858) thought that drusen were a 3. Deep papillary haemorrhages hyaline secretion of the retinal pigment epithelium 4. Deep peripapillary subretinal haemorrhage. which was displaced into the optic disc. Although the aetiology of the haemorrhages has Calcium has been demonstrated in optic disc remained obscure, two mechanisms have been drusen in the past (Tobler, 1922; Seitz and Kersting, proposed (Brodrick, I973): I962), but the consistent finding of calcium in all optic disc drusen studied led us to one of two con- i. Mechanical erosion of an adjacent blood vessel clusions. Either all optic disc drusen are calcified or by a progressively enlarging drusen, or calcium is deposited as optic disc drusen age. Since 2. Congestion and venous stasis producing a the youngest patient in our study was 40 years old, condition akin to papilloedema. we could not adequately test the first hypothesis. In our series two eyes showed small haemorrhages Nowhere in the literature, however, is there any on the disc while a third case demonstrated the mention of the presence or absence of iron in associa- sequelae of a previous bilateral juxtapapillary tion with drusen. In several cases, both the drusen haemorrhage. In each instance the proximity of the and the juxtapapillary scar stained strongly positive disc drusen to blood vessels was readily apparent and with Perls' stain, indicating the presence of (ferric) presumably responsible for the haemorrhage. iron. It is well known that when red blood cells as in a are Histochemically (Table II), drusen are insoluble in escape into the tissues, haemorrhage, they copyright. water, ethanol, and ether. They are not birefringent phagocytosed by macrophages, which convert their and they stain negatively for amyloid and fibrin. In haemoglobin to haemosiderin. The accumulated ultraviolet light they exhibit autofluorescence (Kelley, haemosiderin lends to the tissues an irregular gran- 1974). They are periodic acid-Schiff positive and ularity and is responsible for the positive reaction with stain positively for amino acids and acid muco- an iron stain. The retinal scar in one of our cases polysaccharides. Tobler (1922) felt they were a also showed some endothelial lined channels which could be new vessels; this adds more credence to the

possibility of pre-existent haemorrhage. http://bjo.bmj.com/ Table II* Histochemical reactions of optic disc drusen Exogenous iron, which is histochemically in- distinguishable from haemosiderin, can be found in relation to retained intraocular (ferrous) foreign Test or reaction Results bodies, and lead to siderosis bulbi. If rapidly en- capsulated by organizing haemorrhage, the resulting siderosis is localized to the surrounding tissues. Solubility reactions Acetic acid Insoluble However, no foreign body was detected in any eye on September 25, 2021 by guest. Protected Ethanol Insoluble studied, nor was there any history of earlier ocular Ether Insoluble trauma. Repeated intraocular haemorrhages may Potassium hydroxide, dilute Insoluble lead to haemosiderosis bulbi, but this was not the Sodium hydroxide, dilute Insoluble case here. Water Insoluble Pathologically, haemosiderin must be differentiated Xylene Insoluble from haemoglobin and acid haematin, seen as an Staining reactions artefact produced by the action of formalin or other Acid mucopolysaccharides Present acid fixatives on haemoglobin. Both of these stain Amino acids (arginine, negatively with Perls' stain, and in addition, acid tryptophan, or tryosine) Present Calcium Present haematin is birefringent. In the drusen itself, the Congo red (amyloid) Negative presence of iron could, therefore, represent haemorr- Periodic acid-Schiff reagent Positive hage around it, or could mean that drusen contain Weigert stain (fibrin) Negative iron as an intrinsic chemical component. In the Iron (Perls' stain) Positive (in some cases) retinal scar, its deposition merely indicates previous Other haemorrhage in that area, presumably due to the Polarized light Not birefringent adjacent drusen. Autofluorescence Positive In one instance we observed optic disc drusen associated with (an incidence of * (After Lorentzen) 014 per cent of the necropsies). The clinical associa- Drusen of the optic disc 421 Br J Ophthalmol: first published as 10.1136/bjo.59.8.413 on 1 August 1975. Downloaded from tion between the two conditions has been reported by Summary a number of observers. Petersen (1957) observed A retrospective study of 737 consecutive necropsies clinically four cases of disc drusen in 47 cases of yielded I5 cases of drusen of the optic nerve head, an retinitis pigmentosa. Lorentzen (I966), in a study of incidence of 20-4 cases per thousand. This represents 70 cases of retinitis pigmentosa, found only one with the highest incidence yet reported. The histopatho- drusen. In addition, the association between angioid logical features of drusen of the nerve head included streaks and optic disc drusen has been clinically elevation of the nerve head, compression of optic reported (Krill and others, I973), but we did not nerve fibres, partial optic atrophy, cytoid bodies, encounter a case of and drusen of the disc haemorrhages, juxtapapillary retinal scarring disc. with haemosiderin deposition, calcification, and iron deposition within drusen.

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WOLTER, J. R., and FALLS, H. F. (I962) Arch. Ophthal., 68, 2I9 copyright. http://bjo.bmj.com/ on September 25, 2021 by guest. Protected