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Retinal Fluorescein Leakage in Retinitis Pigmentosa: Reply
674
November, 1986
AMERICAN JOURNAL OF OPHTHALMOLOGY
of the favorable inner diameter/outer diameter ratio. We confirmed the importance of the tip dimensions as opposed to viscosity or surface tension of the formulation by testing the Phospholine Iodide solution with the Isoptocarpine tip and vice versa. For both dropper tips, the eyedrop size delivered remained the same (±2 IJ-I) regardless of which solution was used. We congratulate Drs. Lederer and Harold for their thorough analysis of the size of commonly prescribed eyedrops. However, if decreasing eyedrop size is shown to be an improvement in topical therapy, it will be important to understand how to produce smaller drops. REAY H. BROWN, M.D. MARY G. LYNCH, M.D. Dallas, Texas
Reference 1. Brown, R. H., Hotchkiss, M. 1., and Davis, E. B.: Creating smaller eyedrops by reducing eyedropper tip dimensions. Am. J. Ophthalmol. 99:460, 1985.
Retinal Fluorescein Leakage in Retinitis Pigmentosa EDITOR: In the article, "Retinal fluorescein leakage in retinitis pigmentosa" (Am. J. Ophthalmol. 101:354, March 1986) by D. A. Newsome, in describing the methods of the study, the author states that fluorescein angiographic photographs with a 30- or a 60-degree camera were centered on the disk (field I) or on the macula (field II). We believe this may be the cause of the low incidence of dye leakage found in the periphery (nine eyes of 118). In the discussion the author states: "From the present study it seems reasonable to conclude that primary breakdown of the bloodretinal barrier in retinitis pigmentosa occurs at the level of the retinal pigment epithelium." Those who deal with fluorescein angiography in retinitis pigmentosa know that in
early phases of good quality angiograms diffuse retinal microvascular abnormalities can be seen extending not only in the posterior pole but also in the midperiphery and in the periphery. They can lead to a diffuse dye leakage in the retina that is particularly visible in the macular area. 1 Around the retinal vessel wall a relatively capillary-free zone exists. This is more evident near the retinal arterioles" and it can appear as a hypofluorescent muff in sharply defined angiograms. If extensive dye leakage occurs, this periarteriolar hypofluorescent halo becomes more visible on contrast. This typical angiographic feature can be seen in different ocular diseases, such as uveitis; its presence indicates that diffuse capillary leakage exists. Even in retinitis pigmentosa late phase angiograms may show this pattern (the Figure of this correspondence and Figure 1, bottom left, of the article), thus indicating that a blood-retinal barrier breakdown occurs at the level of retinal capillaries, which contrasts with Newsome's conclusions. A dye leakage from the retinal pigment epithelium is not likely to create such a particular angiographic aspect. Furthermore, the author draws his conclusions by observation of stereoscopic pairs of the posterior pole. Though we find it is difficult in this disease to discern the level of dye leakage in the macular area, it may merely demonstrate where the dye is but not where the dye comes from. STEFANO PIERMAROCCHI, M.D. TATIANA SEGATO, M.D. EDOARDO MIDENA, M.D. Padua, Italy
References 1. Schatz, H., Burton, T. C., Yannuzzi, 1. A., and Rabb, M. F.: Interpretation of Fundus Fluorescein Angiography. St. Louis, C. V. Mosby Company, 1978, p. 588. 2. Sigelman, J.: Retinal Diseases, 1st ed. Boston, Little, Brown and Company, 1984, p. 47
_ _ _ _ _ _ _ Reply
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EDITOR: Dr. Piermarocchi and colleagues have emphasized one of the difficulties and limitations in the interpretation of clinical fluorescein angiography. As indicated in my article, it is
Vol. 102, No. 5
Correspondence
675
Figure (Piermarocchi, Segato, and Midena). Fluorescein angiography of an eye affected by retinitis pigmentosa. Early phases show diffuse capillary abnormalities in the posterior pole and in midperiphery, a hypofluorescent periarteriolar halo is visible (left) and it becomes more evident in late phases when extensive dye leakage occurs (right). difficult to be certain about the sites of fluorescein dye leakage, particularly when the amount of leakage is great. By light scatter and other mechanisms widespread fluorescence obscures many details of the fundus that might otherwise be seen. It has been my experience, reported in part in my article, to discern dye appearance at the level of the pigment epithelium in many cases early in the angiogram. With a diseased retina, one must be concerned about the possibility that dye may be leaking from deeper retinal capillaries. In many cases of retinitis pigmentosa dye accumulation can be seen at the level of the retinal pigment epithelium in the foveal avascular zone. When dye is seen accumulating here and not leaking from the perifoveal capillaries, it seems reasonable to conclude that the outer blood ocular barrier, the retinal pigment epithelium, is compromised. I agree
with Dr. Piermarocchi and colleagues that once dye has accumulated, it is impossible to be certain from where it leaked. In the case illustrated in their correspondence, it is easy to decide that the leakage is associated with the abnormally prominent retinal microvasculature. Although this can be seen in some eyes with retinitis pigmentosa, it is certainly not pathognomonic of retinitis pigmento sa and is not typically seen. The retinitis pigmentosa process may share some mechanisms of blood ocular barrier compromise with some forms of uveitis. Understanding of these common mechanisms should increase our knowledge of a variety of diseases. DAVID A. NEWSOME, M.D.
New Orleans, Louisiana
November, 1986
AMERICAN JOURNAL OF OPHTHALMOLOGY
of the favorable inner diameter/outer diameter ratio. We confirmed the importance of the tip dimensions as opposed to viscosity or surface tension of the formulation by testing the Phospholine Iodide solution with the Isoptocarpine tip and vice versa. For both dropper tips, the eyedrop size delivered remained the same (±2 IJ-I) regardless of which solution was used. We congratulate Drs. Lederer and Harold for their thorough analysis of the size of commonly prescribed eyedrops. However, if decreasing eyedrop size is shown to be an improvement in topical therapy, it will be important to understand how to produce smaller drops. REAY H. BROWN, M.D. MARY G. LYNCH, M.D. Dallas, Texas
Reference 1. Brown, R. H., Hotchkiss, M. 1., and Davis, E. B.: Creating smaller eyedrops by reducing eyedropper tip dimensions. Am. J. Ophthalmol. 99:460, 1985.
Retinal Fluorescein Leakage in Retinitis Pigmentosa EDITOR: In the article, "Retinal fluorescein leakage in retinitis pigmentosa" (Am. J. Ophthalmol. 101:354, March 1986) by D. A. Newsome, in describing the methods of the study, the author states that fluorescein angiographic photographs with a 30- or a 60-degree camera were centered on the disk (field I) or on the macula (field II). We believe this may be the cause of the low incidence of dye leakage found in the periphery (nine eyes of 118). In the discussion the author states: "From the present study it seems reasonable to conclude that primary breakdown of the bloodretinal barrier in retinitis pigmentosa occurs at the level of the retinal pigment epithelium." Those who deal with fluorescein angiography in retinitis pigmentosa know that in
early phases of good quality angiograms diffuse retinal microvascular abnormalities can be seen extending not only in the posterior pole but also in the midperiphery and in the periphery. They can lead to a diffuse dye leakage in the retina that is particularly visible in the macular area. 1 Around the retinal vessel wall a relatively capillary-free zone exists. This is more evident near the retinal arterioles" and it can appear as a hypofluorescent muff in sharply defined angiograms. If extensive dye leakage occurs, this periarteriolar hypofluorescent halo becomes more visible on contrast. This typical angiographic feature can be seen in different ocular diseases, such as uveitis; its presence indicates that diffuse capillary leakage exists. Even in retinitis pigmentosa late phase angiograms may show this pattern (the Figure of this correspondence and Figure 1, bottom left, of the article), thus indicating that a blood-retinal barrier breakdown occurs at the level of retinal capillaries, which contrasts with Newsome's conclusions. A dye leakage from the retinal pigment epithelium is not likely to create such a particular angiographic aspect. Furthermore, the author draws his conclusions by observation of stereoscopic pairs of the posterior pole. Though we find it is difficult in this disease to discern the level of dye leakage in the macular area, it may merely demonstrate where the dye is but not where the dye comes from. STEFANO PIERMAROCCHI, M.D. TATIANA SEGATO, M.D. EDOARDO MIDENA, M.D. Padua, Italy
References 1. Schatz, H., Burton, T. C., Yannuzzi, 1. A., and Rabb, M. F.: Interpretation of Fundus Fluorescein Angiography. St. Louis, C. V. Mosby Company, 1978, p. 588. 2. Sigelman, J.: Retinal Diseases, 1st ed. Boston, Little, Brown and Company, 1984, p. 47
_ _ _ _ _ _ _ Reply
_
EDITOR: Dr. Piermarocchi and colleagues have emphasized one of the difficulties and limitations in the interpretation of clinical fluorescein angiography. As indicated in my article, it is
Vol. 102, No. 5
Correspondence
675
Figure (Piermarocchi, Segato, and Midena). Fluorescein angiography of an eye affected by retinitis pigmentosa. Early phases show diffuse capillary abnormalities in the posterior pole and in midperiphery, a hypofluorescent periarteriolar halo is visible (left) and it becomes more evident in late phases when extensive dye leakage occurs (right). difficult to be certain about the sites of fluorescein dye leakage, particularly when the amount of leakage is great. By light scatter and other mechanisms widespread fluorescence obscures many details of the fundus that might otherwise be seen. It has been my experience, reported in part in my article, to discern dye appearance at the level of the pigment epithelium in many cases early in the angiogram. With a diseased retina, one must be concerned about the possibility that dye may be leaking from deeper retinal capillaries. In many cases of retinitis pigmentosa dye accumulation can be seen at the level of the retinal pigment epithelium in the foveal avascular zone. When dye is seen accumulating here and not leaking from the perifoveal capillaries, it seems reasonable to conclude that the outer blood ocular barrier, the retinal pigment epithelium, is compromised. I agree
with Dr. Piermarocchi and colleagues that once dye has accumulated, it is impossible to be certain from where it leaked. In the case illustrated in their correspondence, it is easy to decide that the leakage is associated with the abnormally prominent retinal microvasculature. Although this can be seen in some eyes with retinitis pigmentosa, it is certainly not pathognomonic of retinitis pigmento sa and is not typically seen. The retinitis pigmentosa process may share some mechanisms of blood ocular barrier compromise with some forms of uveitis. Understanding of these common mechanisms should increase our knowledge of a variety of diseases. DAVID A. NEWSOME, M.D.
New Orleans, Louisiana