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New vessel formation beneath the retinal pigment epithelium in senile eyes
296
SurvOphthalmol
1976
CURRENTOPHTHALMOLOGY
age has an effect. Topographically, a distinction can be made between superficial and visible drusen of the optic disc and deep-seated drusen of the terminus (head) of the optic nerve. Histochemically, there is agreement that drusen consist of hyalin or hyalin-like compounds. Clinically, three forms can be distinguished: (1) drusen of the optic disc in acquired eye diseases (this is a long list, including neuritis, glaucoma, tumors, atrophies, trauma, congenital cataract, chorioretinitis, etc.); (2) hereditary degenerative diseases (e.g. retinitis pigmentosa, macular diseases, etc.); (3) idiopathic drusen (15 1 cases reported in the literature). On the basis of their own examinations the authors have concluded that, although the syndrome is described in the literature as a distinctive disease entity by itself (sui generis), comparable changes occur in other parts of the body, notably in the eye and brain. In the eye, in addition to accumulating masses of hyalin, there may also occur accumulations of amyloid bodies and “pseudochalk.” The occurrence of colloids in the retina has also been reported. Consequently, one must distinguish between drusen, colloid bodies, pseudochalk, corpora amylacea and corpora arenacea. It is best to distinguish among the following: (1) corpora amylacea of the optic nerve, (2) corpora arenacea of the optic nerve sheath, (3) drusen of the terminus (head) of the optic nerve, (4) colloid bodies in the same area and in the retina, (5) socalled drusen of the glass membrane in phthisis bulbi. These deposits in the eye have similarities in common and common chemical relationships. The deposits occur in the form of droplets with a tendency for appositional growth in the form of Liesegang rings, which are typical of colloids. They occur preferentially on membranes, metabolic barriers and anatomical strictures. A disturbance of the true colloid state tends to lead to a deposition of colloidal material. This deposition can be reversible, partially reversible or irreversible. Perhaps, the formation of drusen on the optic disc, optic nerve or other regions of the eye could be the result of dyscolloidosis due to a local or general disturbance of colloid balance. Perhaps, approaching the problem from the point of view of colloid chemistry may lead to a better understand-
ing of the nature of drusen. If there is no evidence of local disease, a cerebral tumor ought to be suspected. The etiology of corpora amylacea of the optic nerve is purely speculative and might be gliogenic, neurogenic, lymphogenic or hematogenic in origin. Corpora arenacea of the optic nerve sheath is invariably found in enucleated eyes. Its configuration (structure) is typical. Drusen on the terminus (head) of the optic nerve are situated in and anterior to the lamina cribrosa. There exist several histologic forms. They have a tendency toward early calcification and appositional growth. Drusen are formed around condensation nuclei and may reach considerable size. They consist of protein, carbohydrates and calcium (pseudochalk). Colloid bodies in the terminus (head) of the optic nerve and in the retina are small, hyalin spherules which do not increase in size. They consist of mucopolysaccharides and glycogen. They occur frequently in the eyes of diabetics and arteriosclerotic patients. The so-called drusen of the glass membrane are often seen. They form the anatomic substrate for the so-called “hole-forming degeneration of pigmented epithelium” and are frequently described ophthalmoscopically as the “drusen-like degeneration of the glass membrane.” These drusen consist of hyalin substances, which differ widely even in the same eye. The hyalin substances strongly resemble colloids. The formation of drusen is discussed in great detail from the point of view of colloid chemistry.
20 (4) January-February
New Vessel Formation Eyes, by SH Sarks. Br J
Beneath
Ophthalmol
Comment As with many other lesions in the eye, the pathogenesis of disc drusen are still a matter of speculation. This very extensive and well illustrated paper outlines the various theories concerning the formation of optic disc drusen, as well as considering other lesions such as corpora amylacea, corpora arenacea, and several other hyalin-like lesions. The authors relate these lesions to disturbance in colloid formation. As with other theories and concepts about disc drusen, only time will tell. PAUL HENKIND
the Retinal
Pigment
Epithelium
in Senile
57: 951-965, 1973
Hemorrhage beneath the retinal pigment epithelium, thought to arise from a diseased senile disciform choriocapillaris, produces
degeneration. Often subretinal neovascularization exists in such eyes, suggesting that hemorrhage or exudation may be caused by vessels on the inner
297
CURRENTOPHlWALMOLOGY
surface of Bruch’s membrane. Neovascularization has been identified in many cases once the retina has been elevated by exudate, hemorrhage, or fibrovascular tissue, but the exact frequency of new vessel formation in senile eyes has not been determined, nor has it been described clinically or histologically. The eyes of 80 patients with an average age of 78.1 years were examined clinically and pathologically. Macular disturbances were divided into groups and photographed if possible. Postmortem eyes were fixed in neutral formalin, doubleembedded, and examined macroscopically. Serial sections were cut horizontally through the central area to include the disc and macula. Neovascularization through Bruch’s membrane was detected histologically in the vicinity of the macula (30 eyes), adjacent to the disc and in the periphery (18 eyes). Vessels near the macula were traced through gaps in Bruch’s membrane. In 46 eyes with disc and peripheral neovascularization, capillaries were found on Bruch’s membrane without demonstrable breaks in the membrane; 15 of these did show breaks in other areas of the eye. Neovascularization in the vicinity of the macula was characterized by colloid bodies, with and without an associated pigmentary disturbance; the retinal epithelium rested on Bruch’s membrane, which was thickened and hyalinized. Neovascularization around the disc showed vessels passing through Bruch’s membrane and vessels growing around the termination of Bruch’s membrane. New vessels at the periphery were noted in connective tissue and in confluent colloid material. Generally, neovascularization was observed during degeneration and rupture of Bruch’s membrane at the site of deposit of colloid material, during arteriosclerosis of the choroid, or other ocular disease. Observations reveal that neovascularization may be implicated in the pathogenesis of disciform degeneration, serous exudation, and hemorrhage
Instrument
Myopia,
by RT Hennessy.
and scarring. The obliteration of newly formed capillaries may delay the growth of fibrovascular and other complications; however, tissue histological findings suggest that the effect would be temporary since degenerative changes in the pigment epithelium and Bruch’s membrane were widespread and since neovascularization was often multifocal.
Comment An abstract does not do justice to this magnificient article by Sarks. The table provided with the paper is most enlightening. The author examined 50 eyes with clinically normal-appearing maculae and in none of these was he able to demonstrate subretinal neovascularization in the macular region. On the other hand, in eyes with a variety of macular disturbances, including pigmentary clumping, senile choroidal sclerosis, and senile disciform degeneration, there was an exceptionally high incidence of subretinal neovascularization in the macular region. Sarks was able to trace the new vessels from the choroid through ruptures in Bruch’s membrane. While certainly not conclusive, the results of this study do, indeed, suggest the role of subretinal neovascularization arising from choroid in the pathogenesis of disciform macular degeneration. It is, of course, impossible to answer with finality that the vascular alterations were not secondary to the disciform process, but from Sarks’ results, this seems to be unlikely. Another important finding of this paper is that, while neovascularization between Bruch’s membranes and the retinal pigment epithelium can be found at the disc, this does not seem to be a cause for senile macular degeneration as postulated by others. I feel that this article should be read in its entirety by anyone interested in retinal disease. PAUL HENKIND
J Opt Sot Am 6.5:1114-1121, 1975
Instrument myopia is characterized by a persistent state of overaccommodation during observation through an optical instrument such as a telescope or microscope. This overaccommodation has been inferred from the adjustment of focus of the instrument and has an average value of 2.25 diopters with a range from 0.5 to 5.0 diopters.
Since these instruments have been designed to emit parallel rays into the eyes of the observer, overaccommodation seems to serve no biologic purpose. The specific stimulus for this overaccommodation has until now eluded experimenters. The most popular theory has been that the observer, knowing that the object of interest is close at hand,
SurvOphthalmol
1976
CURRENTOPHTHALMOLOGY
age has an effect. Topographically, a distinction can be made between superficial and visible drusen of the optic disc and deep-seated drusen of the terminus (head) of the optic nerve. Histochemically, there is agreement that drusen consist of hyalin or hyalin-like compounds. Clinically, three forms can be distinguished: (1) drusen of the optic disc in acquired eye diseases (this is a long list, including neuritis, glaucoma, tumors, atrophies, trauma, congenital cataract, chorioretinitis, etc.); (2) hereditary degenerative diseases (e.g. retinitis pigmentosa, macular diseases, etc.); (3) idiopathic drusen (15 1 cases reported in the literature). On the basis of their own examinations the authors have concluded that, although the syndrome is described in the literature as a distinctive disease entity by itself (sui generis), comparable changes occur in other parts of the body, notably in the eye and brain. In the eye, in addition to accumulating masses of hyalin, there may also occur accumulations of amyloid bodies and “pseudochalk.” The occurrence of colloids in the retina has also been reported. Consequently, one must distinguish between drusen, colloid bodies, pseudochalk, corpora amylacea and corpora arenacea. It is best to distinguish among the following: (1) corpora amylacea of the optic nerve, (2) corpora arenacea of the optic nerve sheath, (3) drusen of the terminus (head) of the optic nerve, (4) colloid bodies in the same area and in the retina, (5) socalled drusen of the glass membrane in phthisis bulbi. These deposits in the eye have similarities in common and common chemical relationships. The deposits occur in the form of droplets with a tendency for appositional growth in the form of Liesegang rings, which are typical of colloids. They occur preferentially on membranes, metabolic barriers and anatomical strictures. A disturbance of the true colloid state tends to lead to a deposition of colloidal material. This deposition can be reversible, partially reversible or irreversible. Perhaps, the formation of drusen on the optic disc, optic nerve or other regions of the eye could be the result of dyscolloidosis due to a local or general disturbance of colloid balance. Perhaps, approaching the problem from the point of view of colloid chemistry may lead to a better understand-
ing of the nature of drusen. If there is no evidence of local disease, a cerebral tumor ought to be suspected. The etiology of corpora amylacea of the optic nerve is purely speculative and might be gliogenic, neurogenic, lymphogenic or hematogenic in origin. Corpora arenacea of the optic nerve sheath is invariably found in enucleated eyes. Its configuration (structure) is typical. Drusen on the terminus (head) of the optic nerve are situated in and anterior to the lamina cribrosa. There exist several histologic forms. They have a tendency toward early calcification and appositional growth. Drusen are formed around condensation nuclei and may reach considerable size. They consist of protein, carbohydrates and calcium (pseudochalk). Colloid bodies in the terminus (head) of the optic nerve and in the retina are small, hyalin spherules which do not increase in size. They consist of mucopolysaccharides and glycogen. They occur frequently in the eyes of diabetics and arteriosclerotic patients. The so-called drusen of the glass membrane are often seen. They form the anatomic substrate for the so-called “hole-forming degeneration of pigmented epithelium” and are frequently described ophthalmoscopically as the “drusen-like degeneration of the glass membrane.” These drusen consist of hyalin substances, which differ widely even in the same eye. The hyalin substances strongly resemble colloids. The formation of drusen is discussed in great detail from the point of view of colloid chemistry.
20 (4) January-February
New Vessel Formation Eyes, by SH Sarks. Br J
Beneath
Ophthalmol
Comment As with many other lesions in the eye, the pathogenesis of disc drusen are still a matter of speculation. This very extensive and well illustrated paper outlines the various theories concerning the formation of optic disc drusen, as well as considering other lesions such as corpora amylacea, corpora arenacea, and several other hyalin-like lesions. The authors relate these lesions to disturbance in colloid formation. As with other theories and concepts about disc drusen, only time will tell. PAUL HENKIND
the Retinal
Pigment
Epithelium
in Senile
57: 951-965, 1973
Hemorrhage beneath the retinal pigment epithelium, thought to arise from a diseased senile disciform choriocapillaris, produces
degeneration. Often subretinal neovascularization exists in such eyes, suggesting that hemorrhage or exudation may be caused by vessels on the inner
297
CURRENTOPHlWALMOLOGY
surface of Bruch’s membrane. Neovascularization has been identified in many cases once the retina has been elevated by exudate, hemorrhage, or fibrovascular tissue, but the exact frequency of new vessel formation in senile eyes has not been determined, nor has it been described clinically or histologically. The eyes of 80 patients with an average age of 78.1 years were examined clinically and pathologically. Macular disturbances were divided into groups and photographed if possible. Postmortem eyes were fixed in neutral formalin, doubleembedded, and examined macroscopically. Serial sections were cut horizontally through the central area to include the disc and macula. Neovascularization through Bruch’s membrane was detected histologically in the vicinity of the macula (30 eyes), adjacent to the disc and in the periphery (18 eyes). Vessels near the macula were traced through gaps in Bruch’s membrane. In 46 eyes with disc and peripheral neovascularization, capillaries were found on Bruch’s membrane without demonstrable breaks in the membrane; 15 of these did show breaks in other areas of the eye. Neovascularization in the vicinity of the macula was characterized by colloid bodies, with and without an associated pigmentary disturbance; the retinal epithelium rested on Bruch’s membrane, which was thickened and hyalinized. Neovascularization around the disc showed vessels passing through Bruch’s membrane and vessels growing around the termination of Bruch’s membrane. New vessels at the periphery were noted in connective tissue and in confluent colloid material. Generally, neovascularization was observed during degeneration and rupture of Bruch’s membrane at the site of deposit of colloid material, during arteriosclerosis of the choroid, or other ocular disease. Observations reveal that neovascularization may be implicated in the pathogenesis of disciform degeneration, serous exudation, and hemorrhage
Instrument
Myopia,
by RT Hennessy.
and scarring. The obliteration of newly formed capillaries may delay the growth of fibrovascular and other complications; however, tissue histological findings suggest that the effect would be temporary since degenerative changes in the pigment epithelium and Bruch’s membrane were widespread and since neovascularization was often multifocal.
Comment An abstract does not do justice to this magnificient article by Sarks. The table provided with the paper is most enlightening. The author examined 50 eyes with clinically normal-appearing maculae and in none of these was he able to demonstrate subretinal neovascularization in the macular region. On the other hand, in eyes with a variety of macular disturbances, including pigmentary clumping, senile choroidal sclerosis, and senile disciform degeneration, there was an exceptionally high incidence of subretinal neovascularization in the macular region. Sarks was able to trace the new vessels from the choroid through ruptures in Bruch’s membrane. While certainly not conclusive, the results of this study do, indeed, suggest the role of subretinal neovascularization arising from choroid in the pathogenesis of disciform macular degeneration. It is, of course, impossible to answer with finality that the vascular alterations were not secondary to the disciform process, but from Sarks’ results, this seems to be unlikely. Another important finding of this paper is that, while neovascularization between Bruch’s membranes and the retinal pigment epithelium can be found at the disc, this does not seem to be a cause for senile macular degeneration as postulated by others. I feel that this article should be read in its entirety by anyone interested in retinal disease. PAUL HENKIND
J Opt Sot Am 6.5:1114-1121, 1975
Instrument myopia is characterized by a persistent state of overaccommodation during observation through an optical instrument such as a telescope or microscope. This overaccommodation has been inferred from the adjustment of focus of the instrument and has an average value of 2.25 diopters with a range from 0.5 to 5.0 diopters.
Since these instruments have been designed to emit parallel rays into the eyes of the observer, overaccommodation seems to serve no biologic purpose. The specific stimulus for this overaccommodation has until now eluded experimenters. The most popular theory has been that the observer, knowing that the object of interest is close at hand,