British Journal of Ophthalmology, 1979, 63, 143-144
Editorial: Fluorescein angiography of the iris Papers on iris fluorescein angiography have gradually accumulated over the last 10 years since the first angiograms were reported (Jensen and Lundbaek, 1968a, b), and it therefore is an appropriate time to assess the impact of this investigation on research, diagnosis, and clinical management. Like the vasculature of the retina and the brain iris capillaries have a non-fenestrated endothelium lined with basement membrane and occasional pericytes. In primates the junctions between the endothelial cells are tight with zonula occludentes (Vegge, 1972). Fluorescein will not diffuse through vessel walls when they are equipped with tight intercellular junctions of this type. Damage to iris capillaries may result from anoxia, alteration in the intra- and extravascular pressure, ischaemia, trauma,
rubeosis iridis (Wong, 1972), the early changes in diabetic microangiopathy (Jensen and Lundbaek, 1968a; Freidburg et al., 1972), occlusive disease of retinal arterioles and venules (Kottow et al., 1976), anterior segment ischaemia (Easty and Chignell, 1973), various types of glaucoma (Vannas, 1969), and postoperative cystoid macular oedema (Kottow and Hendrickson, 1975). Much has been learnt about these diseases, and doubtless other interesting information will be reported in the future. The causes of iris neovascularisation are numerous (Gartner and Henkind, 1978), and it is helpful to know whether abnormal vessels are present at an early stage in the disease. This is particularly true in patients with central retinal vein occlusion or diabetes with retinopathy. Fluorescein angiography and inflammation. provides a method to detect the early stages which Experimentally it can be used to study the influence cannot be seen by clinical examination. It allows a of active agents and their antagonists, which can be prediction of the risk of later development of rubeosisadministered either topically or systemically. Follow- iridis or thrombotic glaucoma, which can be ing the discovery by Ambache et al. (1965) that a treated by peripheral retinal ablation (Laatikainen, prostaglandin-like substance was released into the 1977). rabbit's eye in response to mechanical trauma Inflammatory disease of the anterior uvea together Eakins et al. (1972) showed that prostaglandins were with the trauma of various types, including operative produced in experimental uveitis induced with bovine trauma, may merely increase vascular permeability, serum albumin. Whitelocke and Eakins (1973) used which is difficult to determine by observation alone fluorescein angiography to demonstrate changes in and can be seen as an increased leakage of fluoresceincalibre and permeability of blood vessels in rabbits dye into the anterior chamber. With advances in after topical application of prostaglandins, and methods of fluorophotometry, measurement of the reported that the substantial increase in vascular concentration of dye in the anterior chamber can be permeability could be reduced by prior treatment made (Maurice, 1963; Trevor-Smith et al., 1977), with polyphoretin phosphate. Similar techniques which may short-cut the necessity of photographic have been employed experimentally to study the techniques where quantitative measurements of dye degenerative release of norepinephrine. This causes concentration cannot be made. transient ocular inflammation, which has been In short, iris angiography is likely to be of considered to be mediated by prostaglandins, and considerable value in the early detection of neovasthese can be counteracted with suitable antagonists cularisation and will continue to provide one method (Neufeld et al., 1973). Iris angiography would be for the experimental investigation of anti-inflammaexpected to continue to be of use in similar experi- tory therapy in the laboratory and in clinical trials. mental situations, and in particular such models In this issue of the BJO 3 papers concern iris angioprovide a way in which the efficacy of anti- graphy, where the uses for the technique are inflammatory drugs may be tested. It can likewise be amplified. Dr Laatikainen has followed the iris used in man to investigate the value of topical vascular changes in patients with diabetic retinotherapy of uveitis or postoperative inflammation. pathy, and as a result has been able to classify In studies of eye disease many investigators have precisely the lesions which she has found, providing concentrated on those diseases associated with a system of grading which will be valuable in future vascular lesions in an attempt to learn more about studies of possible treatment modalities. In a second the disease process or to investigate the technique contribution she describes the iris vascular response as an aid to diagnosis. The vascular responses have in a group of patients with uveitis. A third paper, now been well documented in a number of patho- by Drs Brovkina and Chichua, concerns the value logical conditions, including uveitis (Kottow, 1978), of angiography in the diagnosis of iris tumours 143
144
from which histological material was obtained. These 3 papers are an important addition to an expanding field, which has recently been expertly reviewed in a monograph on iris angiography by Kottow (1978). References Ambache, N., Kavanagh, L., and Whiting, W. (1965). Effect of mechanical stimulation in rabbits' eyes: release of active substance in anterior chamber perfusates. Journal of Physiology, 176, 378-408. Eakins, K. E., Whitelocke, R. A., Perkins, E. S., Bennett, A., and Unger, W. G. (1972). Release of prostaglandins in ocular inflammation in the rabbit. Nature New Biology, 239, 248-249. Easty, D. L., and Chignell, A. (1973). Fluorescein angiography in anterior segment ischaemia. British Journal of Ophthalmology, 57, 18-26. Freidburg, D., Schultheiss, K., and Wigger, H. (1972). Fluoreszenzangiographische Befunde bei Rubiosis iridis. Berichte der Deutschen Ophthalmologischen Gesellschaft, 72, 339-343. Gartner, S., and Henkind, P. (1978). Neovascularization of the iris (rubeosis iridis). Survey of Ophthalmology, 22, 291-312. Jensen, V. A., and Lundbaek, K. (1968a). Fluorescein angiography of the iris in recent and long-term diabetes. Diabetologia, 4, 161 -163. Jensen, V. A., and Lundbaek, K. (1968b). Fluorescein angiography of the iris in recent and long-term diabetes: preliminary communication. Acta Ophthalmologica, 46, 584-585. Kottow, M. H. (1978). Anterior Segment Fluorescein Angiography. Williams & Wilkins: Baltimore, Maryland.
Editorial Kottow, M., and Hendrickson, P. (1975). Iris angiography in cystoid macular oedema after cataract extraction. Annali di Ottalmologia e Clinica Oculistica, 93, 487-493. Kottow, M., Metzler, W., and Hendrickson, P. (1976). Iris angiographic findings in retinal vein occlusion. In Vision and Circulation, Proceedings of the Third William MacKenzie Memorial Symposium, Glasgow, 1974, pp. 251-264. Edited by I. S. Cant. Kimpton: London. Laatikainen, L. (1977). Preliminary report on the effect of retinal panphotocoagulation on rubeosis iridis and neovascular glaucoma. British Journal of Ophthalmology, 61, 278-284. Maurice, D. M. (1963). A new objective fluorophotometer. Experimental Eye Research, 2, 33-38. Neufeld, A. H., Chavis, R. M., and Sears, M. L. (1973). Degeneration release of nore-epinephrine causes transient ocular hyperaemia indicated by prostaglandins. Investigative Ophthalmology, 12, 167- 175. Trevor-Smith, A., Jones, D. P., Sturrock, E. D., and Wright, P. (1977). An improved objective slit-lamp fluorophotometer using tungsten-halogen lamp excitation and synchronous detection. British Journal of Ophthalmology, 61, 722-725. Vannas, A. (1969). Fluorescein angiography of the vessels of the iris in pseudoexfoliation of the lens capsule, capsular glaucoma and some other forms of glaucoma. Acta Ophthalmologica, Suppl. 105. Vegge, T. (1972). A study of the ultra structure of the small iris vessels of the verret monkey (Cercopithecus aethiops). Zeitschrift fur Zellforschung und mikroscopische Anatomie, 123, 195-208. Whitelocke, R. A. F., and Eakins, K. E. (1973). Vascular changes in the anterior uvea of the rabbit produced by prostalglandins. Archives of Ophthalmology, 89, 495-499. Wong, I. G. (1972). Clinical use of iris fluorescein angiography. In Current Concepts in Ophthalmology, Vol. 3, pp. 29-40. Edited by F. C. Blodi. Mosby: St. Louis.
Editorial: Fluorescein angiography of the iris Papers on iris fluorescein angiography have gradually accumulated over the last 10 years since the first angiograms were reported (Jensen and Lundbaek, 1968a, b), and it therefore is an appropriate time to assess the impact of this investigation on research, diagnosis, and clinical management. Like the vasculature of the retina and the brain iris capillaries have a non-fenestrated endothelium lined with basement membrane and occasional pericytes. In primates the junctions between the endothelial cells are tight with zonula occludentes (Vegge, 1972). Fluorescein will not diffuse through vessel walls when they are equipped with tight intercellular junctions of this type. Damage to iris capillaries may result from anoxia, alteration in the intra- and extravascular pressure, ischaemia, trauma,
rubeosis iridis (Wong, 1972), the early changes in diabetic microangiopathy (Jensen and Lundbaek, 1968a; Freidburg et al., 1972), occlusive disease of retinal arterioles and venules (Kottow et al., 1976), anterior segment ischaemia (Easty and Chignell, 1973), various types of glaucoma (Vannas, 1969), and postoperative cystoid macular oedema (Kottow and Hendrickson, 1975). Much has been learnt about these diseases, and doubtless other interesting information will be reported in the future. The causes of iris neovascularisation are numerous (Gartner and Henkind, 1978), and it is helpful to know whether abnormal vessels are present at an early stage in the disease. This is particularly true in patients with central retinal vein occlusion or diabetes with retinopathy. Fluorescein angiography and inflammation. provides a method to detect the early stages which Experimentally it can be used to study the influence cannot be seen by clinical examination. It allows a of active agents and their antagonists, which can be prediction of the risk of later development of rubeosisadministered either topically or systemically. Follow- iridis or thrombotic glaucoma, which can be ing the discovery by Ambache et al. (1965) that a treated by peripheral retinal ablation (Laatikainen, prostaglandin-like substance was released into the 1977). rabbit's eye in response to mechanical trauma Inflammatory disease of the anterior uvea together Eakins et al. (1972) showed that prostaglandins were with the trauma of various types, including operative produced in experimental uveitis induced with bovine trauma, may merely increase vascular permeability, serum albumin. Whitelocke and Eakins (1973) used which is difficult to determine by observation alone fluorescein angiography to demonstrate changes in and can be seen as an increased leakage of fluoresceincalibre and permeability of blood vessels in rabbits dye into the anterior chamber. With advances in after topical application of prostaglandins, and methods of fluorophotometry, measurement of the reported that the substantial increase in vascular concentration of dye in the anterior chamber can be permeability could be reduced by prior treatment made (Maurice, 1963; Trevor-Smith et al., 1977), with polyphoretin phosphate. Similar techniques which may short-cut the necessity of photographic have been employed experimentally to study the techniques where quantitative measurements of dye degenerative release of norepinephrine. This causes concentration cannot be made. transient ocular inflammation, which has been In short, iris angiography is likely to be of considered to be mediated by prostaglandins, and considerable value in the early detection of neovasthese can be counteracted with suitable antagonists cularisation and will continue to provide one method (Neufeld et al., 1973). Iris angiography would be for the experimental investigation of anti-inflammaexpected to continue to be of use in similar experi- tory therapy in the laboratory and in clinical trials. mental situations, and in particular such models In this issue of the BJO 3 papers concern iris angioprovide a way in which the efficacy of anti- graphy, where the uses for the technique are inflammatory drugs may be tested. It can likewise be amplified. Dr Laatikainen has followed the iris used in man to investigate the value of topical vascular changes in patients with diabetic retinotherapy of uveitis or postoperative inflammation. pathy, and as a result has been able to classify In studies of eye disease many investigators have precisely the lesions which she has found, providing concentrated on those diseases associated with a system of grading which will be valuable in future vascular lesions in an attempt to learn more about studies of possible treatment modalities. In a second the disease process or to investigate the technique contribution she describes the iris vascular response as an aid to diagnosis. The vascular responses have in a group of patients with uveitis. A third paper, now been well documented in a number of patho- by Drs Brovkina and Chichua, concerns the value logical conditions, including uveitis (Kottow, 1978), of angiography in the diagnosis of iris tumours 143
144
from which histological material was obtained. These 3 papers are an important addition to an expanding field, which has recently been expertly reviewed in a monograph on iris angiography by Kottow (1978). References Ambache, N., Kavanagh, L., and Whiting, W. (1965). Effect of mechanical stimulation in rabbits' eyes: release of active substance in anterior chamber perfusates. Journal of Physiology, 176, 378-408. Eakins, K. E., Whitelocke, R. A., Perkins, E. S., Bennett, A., and Unger, W. G. (1972). Release of prostaglandins in ocular inflammation in the rabbit. Nature New Biology, 239, 248-249. Easty, D. L., and Chignell, A. (1973). Fluorescein angiography in anterior segment ischaemia. British Journal of Ophthalmology, 57, 18-26. Freidburg, D., Schultheiss, K., and Wigger, H. (1972). Fluoreszenzangiographische Befunde bei Rubiosis iridis. Berichte der Deutschen Ophthalmologischen Gesellschaft, 72, 339-343. Gartner, S., and Henkind, P. (1978). Neovascularization of the iris (rubeosis iridis). Survey of Ophthalmology, 22, 291-312. Jensen, V. A., and Lundbaek, K. (1968a). Fluorescein angiography of the iris in recent and long-term diabetes. Diabetologia, 4, 161 -163. Jensen, V. A., and Lundbaek, K. (1968b). Fluorescein angiography of the iris in recent and long-term diabetes: preliminary communication. Acta Ophthalmologica, 46, 584-585. Kottow, M. H. (1978). Anterior Segment Fluorescein Angiography. Williams & Wilkins: Baltimore, Maryland.
Editorial Kottow, M., and Hendrickson, P. (1975). Iris angiography in cystoid macular oedema after cataract extraction. Annali di Ottalmologia e Clinica Oculistica, 93, 487-493. Kottow, M., Metzler, W., and Hendrickson, P. (1976). Iris angiographic findings in retinal vein occlusion. In Vision and Circulation, Proceedings of the Third William MacKenzie Memorial Symposium, Glasgow, 1974, pp. 251-264. Edited by I. S. Cant. Kimpton: London. Laatikainen, L. (1977). Preliminary report on the effect of retinal panphotocoagulation on rubeosis iridis and neovascular glaucoma. British Journal of Ophthalmology, 61, 278-284. Maurice, D. M. (1963). A new objective fluorophotometer. Experimental Eye Research, 2, 33-38. Neufeld, A. H., Chavis, R. M., and Sears, M. L. (1973). Degeneration release of nore-epinephrine causes transient ocular hyperaemia indicated by prostaglandins. Investigative Ophthalmology, 12, 167- 175. Trevor-Smith, A., Jones, D. P., Sturrock, E. D., and Wright, P. (1977). An improved objective slit-lamp fluorophotometer using tungsten-halogen lamp excitation and synchronous detection. British Journal of Ophthalmology, 61, 722-725. Vannas, A. (1969). Fluorescein angiography of the vessels of the iris in pseudoexfoliation of the lens capsule, capsular glaucoma and some other forms of glaucoma. Acta Ophthalmologica, Suppl. 105. Vegge, T. (1972). A study of the ultra structure of the small iris vessels of the verret monkey (Cercopithecus aethiops). Zeitschrift fur Zellforschung und mikroscopische Anatomie, 123, 195-208. Whitelocke, R. A. F., and Eakins, K. E. (1973). Vascular changes in the anterior uvea of the rabbit produced by prostalglandins. Archives of Ophthalmology, 89, 495-499. Wong, I. G. (1972). Clinical use of iris fluorescein angiography. In Current Concepts in Ophthalmology, Vol. 3, pp. 29-40. Edited by F. C. Blodi. Mosby: St. Louis.
