Examination of Macular Vitreoretinal Interface Disorders With Monochromatic Photography Rafael G. Ortiz, M.D., Pedro F. Lopez, M.D., H. M i c h a e l Lambert, M.D., Paul Sternberg, Jr., M.D., and T h o m a s M. Aaberg, M.D.
Monochromatic light accentuates details of different retinal layers because of its variable absorption and reflectance by structures both within and above these layers. Monochromat ic photography was used to examine macular vitreoretinal interface abnormalities in 19 pa tients. Short wavelength photographs (490 nm) provided the best detail of inner retinal abnormalities, including epiretinal mem branes, vitreoretinal traction, and the internal surface of confluent macular edema (pseudocyst). Although 540-nm red-free photography provided acceptable photographs, it did not provide optimal detail of inner or deep retinal abnormalities. Longer wavelengths, 585 and 610 nm, best disclosed the extent of deep retinal abnormalities, including the extent of confluent macular edema (pseudocysts) and retinal detachment that surrounded macular holes. The addition of short- and long-wave length photography to traditional red-free photography may provide better localization, understanding, and documentation of the three-dimensional relationships in macular vitreoretinal interface disorders. M O N O C H R O M A T I C FUNDUS PHOTOGRAPHY takes advantage of the differential transmission, ab sorption, and reflectance of monochromatic light in the layers of the sensory retina, pigment epithelium, and choroid. Although the tech nique has been described for the normal fun-
Accepted for publication Dec. 19, 1991. From the Department of Ophthalmology, Retina Serv ice, Emory University School of Medicine, Atlanta, Georgia. This study was supported in part by a HeedKnapp Ophthalmic Foundation Fellowship (Dr. Lopez) and a departmental grant from Research to Prevent Blindness, Inc., New York, New York. Reprint requests to Pedro F. Lopez, M.D., Emory Eye Center, 1327 Clifton Rd. N.E., Atlanta, GA 30322.
dus, 1 3 clinical application has not become well accepted. Recent advances in vitreous surgical techniques have provided new treatment ap proaches to macular vitreoretinal interface dis orders such as macular holes, impending macu lar holes, vitreomacular traction syndromes, and epiretinal membranes. 4 Preoperative iden tification of the pathoanatomy of macular vit reoretinal interface disorders is an important, but often difficult task. We used monochromatic photography to better delineate macular vitreo retinal interface abnormalities.
Material and Methods Nineteen patients seen at our institution were referred for monochromatic fundus pho tography. Patients with media opacities pre venting adequate polychromatic fundus pho tography were excluded. Selection criteria included vitreomacular traction syndromes, macular holes (full thickness, impending, and lamellar), macular pseudocysts, and epiretinal membranes. Referring diagnoses included five full-thickness macular holes, three epiretinal membranes, one lamellar hole, three cases of confluent macular edema (pseudocysts), three vitreomacular traction syndromes, and one im pending macular hole. The term confluent mac ular edema or pseudocyst is used in preference to macular cyst because macular cyst anatomi cally implies the presence of an epithelial-lined cavity, which conflicts with previous clinicopathologic observations in similar lesions. 6 Two of the patients had both preoperative and post operative photographs. Three patients were re ferred without specific diagnoses. All photogra phy was performed with a fundus camera that used 10-nm narrow-band interference filters of 490, 540, 585, 610, and 640 nm. Each of us reviewed the photographs. The photographs were evaluated with regard to delineation of
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retinal and choroidal layers, as well as optimal visualization of abnormalities.
Results Photographs of 490 nm consistently pro duced the best images of posterior vitreous surface and macular inner retinal abnormali ties. Epiretinal membranes appeared more prominent and extensive when photographed with this shorter wavelength than with longer wavelengths (Fig. 1, top and middle). The integ rity of the inner layer (roof) of confluent macu lar edema (pseudocyst) could be easily deter mined (Fig. 2). Internal limiting membrane tension lines (striae) and focal tractional epi centers that were invisible during polychromat ic or red-free photography became evident with short-wavelength (490-nm) monochromatic evaluation. In one case, a partial posterior vitreous detachment with associated vitreomacular traction was recorded in detail with stereoscopic short-wavelength monochromatic photography (Fig. 3). Photographs taken with the 540-nm filter provided better outer retinal detail in the macu lar area than did photographs taken with the 490-nm filter. Inner retinal details, however, were less accentuated with the 540-nm wave length. Outer retinal abnormalities in the mac ular area were best identified with the 585- and 610-nm filters (Fig. 1, bottom). These wave lengths were also best for determining both retinal detachments that surrounded macular holes and the extent of confluent macular ede ma (pseudocyst; Fig. 4). The foveal elevation of
Fig. 1 (Ortiz and associates). Postoperative fundus photographs after pars plana vitrectomy and mem brane stripping for confluent macular edema (pseu docyst) with epiretinal membrane. A small hole in the inner layer of the pseudocyst was extended dur ing the procedure. Top, Note the extent of the epireti nal membrane and internal limiting membrane stri ae. Arrows indicate defects in epiretinal membrane (490 nm). Middle, Inner retinal striae are less appar ent while deep retinal structures are seen with more detail (540 nm). Bottom, This wavelength penetrates macular luteal pigment, allowing better appreciation of deep retinal details. The extent of the confluent macular edema (pseudocyst) is best seen. Arrows indicate true holes within the inner layer (roof) of the confluent macular edema (pseudocyst; 610 nm).
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Fig. 2 (Ortiz and associates). Confluent macular edema (pseudocyst). Top, The inner layer (roof) of the confluent macular edema (pseudocyst) is seen to be intact (490 nm). Bottom, Details of the inner layer of the pseudocyst are more difficult to identify (540 nm). an impending macular hole, although seen on color and 540-nm photographs, was seen in finer detail with the 610-nm filter (Fig. 5). The 610-nm filter provided better detail than did the 585-nm filter. Although the 640-nm filter provided the least information on the macular vitreoretinal inter face, it did expose previously unrecognized choroidal pigmentary changes deep to an area of confluent macular edema (pseudocyst). This wavelength, however, was found to be the least useful in delineating actual vitreoretinal inter face abnormalities.
245
Fig. 3 (Ortiz and associates). Partial posterior vitre ous detachment with macular traction. Top, Fundus photograph discloses foci of macular traction and extent of remaining posterior hyaloidal attachment (490 nm). Bottom, Although retinal structures are more apparent, the vitreoretinal interface is not easi ly identified (540 nm).
Discussion Monochromatic photography previously has been used to examine fundus abnormalities, including subretinal neovascular membranes, 6 retinal vascular abnormalities, 7,8 and choroidal disorders. 8 Monochromatic light allows a verti-
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cally oriented photographic dissection of the retina and choroid. Longer wavelengths allow deeper penetration into the retina and cho roid.2,9 This lamellar analysis provides an im proved three-dimensional understanding of retinal abnormalities. The shorter-wavelength (490-nm) monochro matic light aids in the visualization of internal limiting membrane and the inner retinal sur face. This observation has been previously re ported. 8,10 The major limitation of short-wave length monochromatic light is absorption by cataracts and other media opacities. The 490nm filter used in this study is readily available because it is identical to the exciter filter in the fundus camera. The intermediate 585- and long 610-nm wavelengths provided better resolution of deep retinal abnormalities in the macular area. These filters were superior to the traditional red-free 540-nm filter in this regard. Delori and associates 9 showed that reflections from the internal limiting membrane are most intense between 450 and 540 nm, and that these reflec tions gradually decrease as the wavelength is increased over 540 nm, becoming virtually undetectable above a wavelength of 600 nm. Luteal pigment may have a role in the varia ble penetration of different wavelengths in the macular area. Luteal pigment absorbs the short er wavelengths and appears dark on 490-nm photographs because its peak optical density is at 460 to 465 nm.11,12 The optical density of macular luteal pigment steeply declines at ap proximately 500 nm and approaches zero at 550 nm.12 Wavelengths more than 550 nm, there fore, have no interference from luteal pigment and would be expected to provide superior resolution capabilities for deep intraretinal structures (Fig. 1). The 610-nm photograph (Fig. 1, bottom) discloses details of the conflu ent macular edema including the inner layer (roof) hole in areas that appear dark and with out contrast on 490- and 540-nm photographs. The combination of decreased internal limiting
Fig. 4 (Ortiz and associates). Full-thickness macu lar hole. Top, The epiretinal membrane surrounding the macular hole is best seen with this wavelength (490 nm). Middle, The extent of the epiretinal mem brane is not fully appreciated (540 nm). Bottom, Details within the base of the macular hole are best seen, as is the extent of the surrounding retinal detachment (610 nm).
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t e c h n i q u e for d e l i n e a t i n g the p a t h o a n a t o m y of m a c u l a r v i t r e o r e t i n a l interface d i s o r d e r s . The extent a n d l o c a t i o n of i n n e r r e t i n a l t r a c t i o n striae a n d t r a c t i o n a l e p i c e n t e r s , t h e i n t e g r i t y of the i n n e r layer (roof) of confluent m a c u l a r e d e ma ( p s e u d o c y s t s ) , a n d s e c o n d a r y o u t e r r e t i n a l a b n o r m a l i t i e s m a y b e identified a n d d o c u m e n t ed by u s i n g t h e s e t e c h n i q u e s . This i n f o r m a t i o n may i m p r o v e p r e - a n d p o s t o p e r a t i v e evalua tion, as well as o p t i m i z i n g t h e surgical a p p r o a c h in m a c u l a r p u c k e r , i m p e n d i n g m a c u l a r h o l e , a n d v i t r e o m a c u l a r t r a c t i o n s y n d r o m e sur gical p r o c e d u r e s .
References
Fig. 5 (Ortiz and associates). Top, Impending macular hole (540 nm). Bottom, The extent of the foveal elevation is better appreciated with the 610-nm wavelength. m e m b r a n e reflection a n d d e c r e a s e d interfer ence from luteal p i g m e n t c o n t r i b u t e to the a d v a n t a g e that 5 8 5 - a n d 6 1 0 - n m p h o t o g r a p h s h a v e over 5 4 0 - n m p h o t o g r a p h s for d e e p r e t i n a l a b n o r m a l i t i e s in the m a c u l a r a r e a . Long-wavelength (640-nm) monochromatic light h a s a l i m i t e d role in s t u d y of v i t r e o r e t i n a l interface a b n o r m a l i t i e s ; h o w e v e r , p r e v i o u s l y unrecognized secondary choroidal pigmentary d i s t u r b a n c e s in the m a c u l a r area c o u l d b e i d e n tified a n d d o c u m e n t e d b y u s i n g this w a v e length. M o n o c h r o m a t i c p h o t o g r a p h y is an excellent
1. Behrendt, T., and Wilson, L. A.: Spectral reflec tance photography of the retina. Am. J. Ophthalmol. 59:1079, 1965. 2. Behrendt, T., and Duane, T. D.: Investigation of fundus oculi with spectral reflectance photography. I. Depth and integrity of fundal structures. Arch. Ophthalmol. 75:375, 1966. 3. Delori, F. C , and Gragoudas, E. S.: Examina tion of the ocular fundus with monochromatic light. Ann. Ophthalmol. 8:703, 1976. 4. Smiddy, W. E., Michels, R. G., and Green, W. R.: Morphology, pathology, and surgery of idiopathic vitreoretinal macular disorders. A review. Retina 10:288, 1990. 5. Frangieh, G. T., Green, W. R., and Engel, H. M.: A histopathologic study of macular cysts and holes. Retina 1:311, 1981. 6. Quentel, G., and Coscas, G.: Interet des retinographies en lumiere monochromatique (verte, rouge et bleue) lors de la photocoagulation des membranes neo-vasculaires sous-retiniennes juxta-foveolaires. Bull. Soc. Ophtalmol. Fr. 81:1047, 1981. 7. Kaefer, O.: Degenerative changes in retinal ves sels. Photodocumentation with monochromatic fil ters. Arch. Ophthalmol. 98:303, 1980. 8. Ducrey, N. M., Delori, F. C , and Gragoudas, E. S.: Monochromatic ophthalmoscopy and fundus photography. II. The pathologic fundus. Arch. Oph thalmol. 97:288, 1979. 9. Delori, F. C , Gragoudas, E. S., Francisco, R., and Pruett, R. C : Monochromatic ophthalmoscopy and fundus photography. The normal fundus. Arch. Ophthalmol. 95:861, 1977. 10. Norden, L. C : Spectral reflectance photogra phy of the ocular fundus. Am. J. Optom. Physiol. Opt. 56:586, 1979. 11. Weiter, J. J., Delori, F., and Dorey, C. K.: Cen tral sparing in annular macular degeneration. Am. J. Ophthalmol. 106:286, 1988. 12. Nussbaum, J. J., Pruett, R. C , and Delori, F. C : Historic perspectives macular yellow pigment the first 200 years. Retina 1:296, 1981.
Monochromatic light accentuates details of different retinal layers because of its variable absorption and reflectance by structures both within and above these layers. Monochromat ic photography was used to examine macular vitreoretinal interface abnormalities in 19 pa tients. Short wavelength photographs (490 nm) provided the best detail of inner retinal abnormalities, including epiretinal mem branes, vitreoretinal traction, and the internal surface of confluent macular edema (pseudocyst). Although 540-nm red-free photography provided acceptable photographs, it did not provide optimal detail of inner or deep retinal abnormalities. Longer wavelengths, 585 and 610 nm, best disclosed the extent of deep retinal abnormalities, including the extent of confluent macular edema (pseudocysts) and retinal detachment that surrounded macular holes. The addition of short- and long-wave length photography to traditional red-free photography may provide better localization, understanding, and documentation of the three-dimensional relationships in macular vitreoretinal interface disorders. M O N O C H R O M A T I C FUNDUS PHOTOGRAPHY takes advantage of the differential transmission, ab sorption, and reflectance of monochromatic light in the layers of the sensory retina, pigment epithelium, and choroid. Although the tech nique has been described for the normal fun-
Accepted for publication Dec. 19, 1991. From the Department of Ophthalmology, Retina Serv ice, Emory University School of Medicine, Atlanta, Georgia. This study was supported in part by a HeedKnapp Ophthalmic Foundation Fellowship (Dr. Lopez) and a departmental grant from Research to Prevent Blindness, Inc., New York, New York. Reprint requests to Pedro F. Lopez, M.D., Emory Eye Center, 1327 Clifton Rd. N.E., Atlanta, GA 30322.
dus, 1 3 clinical application has not become well accepted. Recent advances in vitreous surgical techniques have provided new treatment ap proaches to macular vitreoretinal interface dis orders such as macular holes, impending macu lar holes, vitreomacular traction syndromes, and epiretinal membranes. 4 Preoperative iden tification of the pathoanatomy of macular vit reoretinal interface disorders is an important, but often difficult task. We used monochromatic photography to better delineate macular vitreo retinal interface abnormalities.
Material and Methods Nineteen patients seen at our institution were referred for monochromatic fundus pho tography. Patients with media opacities pre venting adequate polychromatic fundus pho tography were excluded. Selection criteria included vitreomacular traction syndromes, macular holes (full thickness, impending, and lamellar), macular pseudocysts, and epiretinal membranes. Referring diagnoses included five full-thickness macular holes, three epiretinal membranes, one lamellar hole, three cases of confluent macular edema (pseudocysts), three vitreomacular traction syndromes, and one im pending macular hole. The term confluent mac ular edema or pseudocyst is used in preference to macular cyst because macular cyst anatomi cally implies the presence of an epithelial-lined cavity, which conflicts with previous clinicopathologic observations in similar lesions. 6 Two of the patients had both preoperative and post operative photographs. Three patients were re ferred without specific diagnoses. All photogra phy was performed with a fundus camera that used 10-nm narrow-band interference filters of 490, 540, 585, 610, and 640 nm. Each of us reviewed the photographs. The photographs were evaluated with regard to delineation of
©AMERICAN JOURNAL OF OPHTHALMOLOGY 113:243-247, M A R C H , 1992
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AMERICAN JOURNAL OF OPHTHALMOLOGY
retinal and choroidal layers, as well as optimal visualization of abnormalities.
Results Photographs of 490 nm consistently pro duced the best images of posterior vitreous surface and macular inner retinal abnormali ties. Epiretinal membranes appeared more prominent and extensive when photographed with this shorter wavelength than with longer wavelengths (Fig. 1, top and middle). The integ rity of the inner layer (roof) of confluent macu lar edema (pseudocyst) could be easily deter mined (Fig. 2). Internal limiting membrane tension lines (striae) and focal tractional epi centers that were invisible during polychromat ic or red-free photography became evident with short-wavelength (490-nm) monochromatic evaluation. In one case, a partial posterior vitreous detachment with associated vitreomacular traction was recorded in detail with stereoscopic short-wavelength monochromatic photography (Fig. 3). Photographs taken with the 540-nm filter provided better outer retinal detail in the macu lar area than did photographs taken with the 490-nm filter. Inner retinal details, however, were less accentuated with the 540-nm wave length. Outer retinal abnormalities in the mac ular area were best identified with the 585- and 610-nm filters (Fig. 1, bottom). These wave lengths were also best for determining both retinal detachments that surrounded macular holes and the extent of confluent macular ede ma (pseudocyst; Fig. 4). The foveal elevation of
Fig. 1 (Ortiz and associates). Postoperative fundus photographs after pars plana vitrectomy and mem brane stripping for confluent macular edema (pseu docyst) with epiretinal membrane. A small hole in the inner layer of the pseudocyst was extended dur ing the procedure. Top, Note the extent of the epireti nal membrane and internal limiting membrane stri ae. Arrows indicate defects in epiretinal membrane (490 nm). Middle, Inner retinal striae are less appar ent while deep retinal structures are seen with more detail (540 nm). Bottom, This wavelength penetrates macular luteal pigment, allowing better appreciation of deep retinal details. The extent of the confluent macular edema (pseudocyst) is best seen. Arrows indicate true holes within the inner layer (roof) of the confluent macular edema (pseudocyst; 610 nm).
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Vitreoretinal Disorders and Monochromatic Photography
Fig. 2 (Ortiz and associates). Confluent macular edema (pseudocyst). Top, The inner layer (roof) of the confluent macular edema (pseudocyst) is seen to be intact (490 nm). Bottom, Details of the inner layer of the pseudocyst are more difficult to identify (540 nm). an impending macular hole, although seen on color and 540-nm photographs, was seen in finer detail with the 610-nm filter (Fig. 5). The 610-nm filter provided better detail than did the 585-nm filter. Although the 640-nm filter provided the least information on the macular vitreoretinal inter face, it did expose previously unrecognized choroidal pigmentary changes deep to an area of confluent macular edema (pseudocyst). This wavelength, however, was found to be the least useful in delineating actual vitreoretinal inter face abnormalities.
245
Fig. 3 (Ortiz and associates). Partial posterior vitre ous detachment with macular traction. Top, Fundus photograph discloses foci of macular traction and extent of remaining posterior hyaloidal attachment (490 nm). Bottom, Although retinal structures are more apparent, the vitreoretinal interface is not easi ly identified (540 nm).
Discussion Monochromatic photography previously has been used to examine fundus abnormalities, including subretinal neovascular membranes, 6 retinal vascular abnormalities, 7,8 and choroidal disorders. 8 Monochromatic light allows a verti-
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cally oriented photographic dissection of the retina and choroid. Longer wavelengths allow deeper penetration into the retina and cho roid.2,9 This lamellar analysis provides an im proved three-dimensional understanding of retinal abnormalities. The shorter-wavelength (490-nm) monochro matic light aids in the visualization of internal limiting membrane and the inner retinal sur face. This observation has been previously re ported. 8,10 The major limitation of short-wave length monochromatic light is absorption by cataracts and other media opacities. The 490nm filter used in this study is readily available because it is identical to the exciter filter in the fundus camera. The intermediate 585- and long 610-nm wavelengths provided better resolution of deep retinal abnormalities in the macular area. These filters were superior to the traditional red-free 540-nm filter in this regard. Delori and associates 9 showed that reflections from the internal limiting membrane are most intense between 450 and 540 nm, and that these reflec tions gradually decrease as the wavelength is increased over 540 nm, becoming virtually undetectable above a wavelength of 600 nm. Luteal pigment may have a role in the varia ble penetration of different wavelengths in the macular area. Luteal pigment absorbs the short er wavelengths and appears dark on 490-nm photographs because its peak optical density is at 460 to 465 nm.11,12 The optical density of macular luteal pigment steeply declines at ap proximately 500 nm and approaches zero at 550 nm.12 Wavelengths more than 550 nm, there fore, have no interference from luteal pigment and would be expected to provide superior resolution capabilities for deep intraretinal structures (Fig. 1). The 610-nm photograph (Fig. 1, bottom) discloses details of the conflu ent macular edema including the inner layer (roof) hole in areas that appear dark and with out contrast on 490- and 540-nm photographs. The combination of decreased internal limiting
Fig. 4 (Ortiz and associates). Full-thickness macu lar hole. Top, The epiretinal membrane surrounding the macular hole is best seen with this wavelength (490 nm). Middle, The extent of the epiretinal mem brane is not fully appreciated (540 nm). Bottom, Details within the base of the macular hole are best seen, as is the extent of the surrounding retinal detachment (610 nm).
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t e c h n i q u e for d e l i n e a t i n g the p a t h o a n a t o m y of m a c u l a r v i t r e o r e t i n a l interface d i s o r d e r s . The extent a n d l o c a t i o n of i n n e r r e t i n a l t r a c t i o n striae a n d t r a c t i o n a l e p i c e n t e r s , t h e i n t e g r i t y of the i n n e r layer (roof) of confluent m a c u l a r e d e ma ( p s e u d o c y s t s ) , a n d s e c o n d a r y o u t e r r e t i n a l a b n o r m a l i t i e s m a y b e identified a n d d o c u m e n t ed by u s i n g t h e s e t e c h n i q u e s . This i n f o r m a t i o n may i m p r o v e p r e - a n d p o s t o p e r a t i v e evalua tion, as well as o p t i m i z i n g t h e surgical a p p r o a c h in m a c u l a r p u c k e r , i m p e n d i n g m a c u l a r h o l e , a n d v i t r e o m a c u l a r t r a c t i o n s y n d r o m e sur gical p r o c e d u r e s .
References
Fig. 5 (Ortiz and associates). Top, Impending macular hole (540 nm). Bottom, The extent of the foveal elevation is better appreciated with the 610-nm wavelength. m e m b r a n e reflection a n d d e c r e a s e d interfer ence from luteal p i g m e n t c o n t r i b u t e to the a d v a n t a g e that 5 8 5 - a n d 6 1 0 - n m p h o t o g r a p h s h a v e over 5 4 0 - n m p h o t o g r a p h s for d e e p r e t i n a l a b n o r m a l i t i e s in the m a c u l a r a r e a . Long-wavelength (640-nm) monochromatic light h a s a l i m i t e d role in s t u d y of v i t r e o r e t i n a l interface a b n o r m a l i t i e s ; h o w e v e r , p r e v i o u s l y unrecognized secondary choroidal pigmentary d i s t u r b a n c e s in the m a c u l a r area c o u l d b e i d e n tified a n d d o c u m e n t e d b y u s i n g this w a v e length. M o n o c h r o m a t i c p h o t o g r a p h y is an excellent
1. Behrendt, T., and Wilson, L. A.: Spectral reflec tance photography of the retina. Am. J. Ophthalmol. 59:1079, 1965. 2. Behrendt, T., and Duane, T. D.: Investigation of fundus oculi with spectral reflectance photography. I. Depth and integrity of fundal structures. Arch. Ophthalmol. 75:375, 1966. 3. Delori, F. C , and Gragoudas, E. S.: Examina tion of the ocular fundus with monochromatic light. Ann. Ophthalmol. 8:703, 1976. 4. Smiddy, W. E., Michels, R. G., and Green, W. R.: Morphology, pathology, and surgery of idiopathic vitreoretinal macular disorders. A review. Retina 10:288, 1990. 5. Frangieh, G. T., Green, W. R., and Engel, H. M.: A histopathologic study of macular cysts and holes. Retina 1:311, 1981. 6. Quentel, G., and Coscas, G.: Interet des retinographies en lumiere monochromatique (verte, rouge et bleue) lors de la photocoagulation des membranes neo-vasculaires sous-retiniennes juxta-foveolaires. Bull. Soc. Ophtalmol. Fr. 81:1047, 1981. 7. Kaefer, O.: Degenerative changes in retinal ves sels. Photodocumentation with monochromatic fil ters. Arch. Ophthalmol. 98:303, 1980. 8. Ducrey, N. M., Delori, F. C , and Gragoudas, E. S.: Monochromatic ophthalmoscopy and fundus photography. II. The pathologic fundus. Arch. Oph thalmol. 97:288, 1979. 9. Delori, F. C , Gragoudas, E. S., Francisco, R., and Pruett, R. C : Monochromatic ophthalmoscopy and fundus photography. The normal fundus. Arch. Ophthalmol. 95:861, 1977. 10. Norden, L. C : Spectral reflectance photogra phy of the ocular fundus. Am. J. Optom. Physiol. Opt. 56:586, 1979. 11. Weiter, J. J., Delori, F., and Dorey, C. K.: Cen tral sparing in annular macular degeneration. Am. J. Ophthalmol. 106:286, 1988. 12. Nussbaum, J. J., Pruett, R. C , and Delori, F. C : Historic perspectives macular yellow pigment the first 200 years. Retina 1:296, 1981.
