Neovascularization of the Iris in Rhegmatogenous Retinal Detachment Sumiyoshi Tanaka, M.D., Hidenao Ideta, M.D., Junichi Yonemoto, M.D., Kiwamu Sasaki, M.D., Akira Hirose, M.D., and Chitoshi Oka, M.D.

To identify conditions associated with neovascularization of the iris in rhegmatogenous retinal detachment, we examined 36 eyes with this disorder seen at our hospital between 1979 and 1990. Clinical courses of disease were divided into the following three groups: (1) neovascularization of the iris without a history of a vitreoretinal operation (four eyes), (2) neovascularization of the iris after an unsuccessful vitreoretinal operation (26 eyes), and (3) neovascularization of the iris after surgical complications (six eyes). In all eyes of Groups 1 and 2, retinal detachment persisted at the onset of iris neovascularization; however, in six eyes, iris neovascularization subsided after retinal reattachment. Characteristic features of Groups 2 and 3 were patient age of 50 years or more, severe myopia, a history of increased intraocular pressure, a history of choroidal detachment, and a large scleral buckle. NEOVASCULARIZATION of the iris in rhegmatogenous retinal detachment is encountered by most vitreoretinal surgeons, but little is known about this phenomenon. Blumenkranz and Hernandez' investigated it in rabbits and Stefansson and associates' investigated it in cats. They concluded that iris neovascularization occurred at a high rate when the retina was artificially detached in eyes on which pars plana vitrectomy and lensectomy had been performed. Uno and associates" reported clinical cases. They studied ten eyes that developed

Accepted for publication Sept. 17, 1991. From Ideta Eye Hospital, Kumamoto, Japan. This study was presented in part at the XIII Congress of the Asia-Pacific Academy of Ophthalmology. Kyoto, Japan, May 17,1991. Reprint requests to Sumiyoshi Tanaka, M.D., Ideta Eye Hospital, 1-35, Gofuku-Machi, Kumamoto City, 860, Japan.

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neovascularization of the iris within six months after an unsuccessful retinal detachment operation. We studied 36 eyes with neovascularization of the iris associated with rhegmatogenous retinal detachment seen at our hospital.

Patients and Methods Our patients were included from the patients with 2,853 consecutive eyes with rhegmatogenous retinal detachment treated at our hospital between 1979 and 1990. Eyes with uveitis before the onset of retinal detachment, eyes with perforating injury or blunt trauma, and eyes with vascular disease of the retina or choroid were excluded because these factors could have influenced development of iris neovascularization. Slit-lamp examination disclosed 36 of 2,853 eyes (1.3%) with abnormal vessels at the edge or surface of the iris, or at the anterior chamber angle during the course of treatment. The 36 eyes were divided into three groups according to the clinical course of disease before the onset of iris neovascularization. Group 1 consisted of four eyes that had no history of a vitreoretinal operation. One eye had no history of any ocular operations, but three were aphakic. Group 2 consisted of 26 eyes with a history of unsuccessful vitreoretinal operations. Of these 26 eyes, 11 had silicone oil in the vitreous, and 15 did not. The six eyes of Group 3 had complications from vitreoretinal operations. Three had mild anterior segment necrosis, whereas the other three had a history of vortex vein damage. The following factors were analyzed in these 36 eyes: (1) incidence of persistent retinal detachment, (2) age, (3) refraction, (4) history of increased intraocular pressure (:2= 25 mm Hg for more than one week), (5) history of choroidal detachment, and (6) size and extent of the scleral buckle.

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Iris Neovascularization in Rhegmatogenous Retinal Detachment

Results

In all eyes of Groups 1 and 2, retinal detachment existed at the onset of iris neovascularization, whereas in two eyes of Group 3 it did not. Retinal detachment was not observed in one eye of Group 3 because of cataract. Iris neovascularization subsided after surgical reattachment of the retina in two eyes of Group 1 and in four eyes of Group 2. In Group 2, consisting of eyes with persistent retinal detachment after an operation, 20 of 26 eyes (77%) were from patients who were 50 years or more of age. We measured refraction in nine eyes and four of these eyes (44 %) were severely myopic « -8 diopters). There was a history of increased intraocular pressure in four of 26 eyes (15%), a history of choroidal detachment in 12 of 21 eyes (57%), a wide scleral buckle of 9 mm or more in 12 of 22 eyes (55%), and a long scleral buckle extending 300 degrees or more in 20 of 24 eyes (83%). In Group 3, consisting of eyes with complications from vitreoretinal operations, four of six eyes (67%) were from patients who were 50 years or more of age. We measured refraction in five eyes and two of these eyes (40%) were severely myopic « - 8 diopters). There was a history of increased intraocular pressure in four of six eyes (67%), a history of choroidal detachment in three of six eyes (50%), a wide scleral buckle of 9 mm or more in four of six eyes (67%), and a long scleral buckle extending 300 degrees or more in four of six eyes (67%). Discussion

Retinal detachment persisted at the onset of iris neovascularization in all eyes of Groups 1 and 2. This was compatible with the experimental animal models of Blumenkranz and Hernandez' and Stefansson and associates," which concluded that eyes without retinal detachment do not develop iris neovascularization. Group 3 was distinguished from the other two groups in that two eyes did not have retinal detachment at the onset of iris neovascularization. Interestingly, iris neovascularization subsided after surgical reattachment of the retina in six eyes of Groups 1 and 2. These clinical facts suggested that persistent retinal detachment had an essential role in the development of iris neovascularization. Bonner' reported nine eyes with retinal neovascularization complicating long-

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term rhegmatogenous retinal detachment caused by trophic holes in the lattice degeneration or by ocular blunt trauma. In eight of these eyes, the retinal new vessel regressed after retinal reattachment. Conversely, Cunha-Vaz, Fonseca, and Vieira" demonstrated by twopoint slit-lamp fluorophotometry that retinal blood flow was decreased in retinal detachment in humans. These reports, along with our study, suggest that decreased retinal circulation provokes neovascularization in eyes with retinal detachment. After retinal reattachment, improved retinal circulation may help the regression of the neovascularization. Patient age of 50 years or more, severe myopia, a history of increased intraocular pressure, a history of choroidal detachment, a wide scleral buckle ~ 9 rnm, and a long scleral buckle ~ 300 degrees were common features of the eyes in our Groups 2 and 3. Using fluorescein angiography, Yoshihara" reported that choroidal circulation was reduced in severely myopic eyes; using the ocular pulse amplitude as an index, Yoshida and associates" had the same result in eyes that had undergone scleral buckling procedures. Aim and BiIl8 reported that an artificial increase in ocular pressure reduced the rate of uveal blood flow in their experimental animal model of cats. On the basis of these reports, we considered the choroidal circulation in the eyes of our Groups 2 and 3 to be decreased. Three eyes ..of Group 3 had a history of vortex vein damage, and the other three eyes had a history of mild anterior segment necrosis. In the experimental animal model of Takahashi," choroidal circulation was reduced in eyes with severed vortex veins, and in the animal model of Hayreh and Baines," a filling defect of fluorescein in the choroid in eyes with occluded posterior ciliary arteries was found. These reports were the basis for our suggestion of a marked decrease of choroidal circulation in our Group 3 eyes with vortex vein damage and anterior segment necrosis in which the ciliary circulation might have been disturbed. Brown and associates" reported 13 eyes with neovascular glaucoma in association with arterial obstructive disease and speculated that choroidal ischemia, in addition to retinal ischemia, might increase the chances of inducing ocular neovascularization, including neovascularization of the iris. That study suggested that, on the basis of persistent retinal detachment, reduced choroidal circulation may contribute to the development of iris neovascularization in rhegmatogenous retinal detachment. Although persistent retinal detachment may have an es-

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sential role in the development of iris neovascularization, the reduced choroidal circulation could have a more important role in some cases. In experimental animal models, Nakamura and associates proposed that iris neovascularization developed in eyes in which the long posterior ciliary arteries were occluded (Nakamura, R., Nakano, E., Wakabayashi, Y., Iwasaki, T., Agawa, T., and Usui, M., 94th Japanese Ophthalmological Society Meeting, May 24, 1990). In the two eyes with anterior segment necrosis in our Group 3, neovascularization of the iris developed without persistent retinal detachment at onset. The mechanism of iris neovascularization in these two eyes may be similar to that in the animal models of Nakamura and associates. We speculated that two factors have an important role in the mechanism of iris neovascularization in rhegmatogenous retinal detachment. Persistent retinal detachment is an essential factor and reduced retinal circulation may lead to iris neovascularization. A second contributory factor may be the reduction of choroidal circulation caused by severe myopia, increased intraocular pressure, large scleral buckle, or surgical complications. Neovascularization of the iris is an ominous prognostic sign of rhegmatogenous retinal detachment. To prevent this condition, prompt reattachment of the retina and efforts to prevent the reduction of choroidal circulation are needed.

References 1. Blumenkranz, M. S., and Hernandez, E.: Rubeosis iridis and vitrectomy. ARVO abstracts. Supple-

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ment to Invest. Ophthalmol. Vis. Sci. St. Louis, C. V. Mosby, 1982, p. 234. 2. Stefansson, E., Landers, M. B. III, Wolbarsht, M. 1., and Klintworth, G. K.: Neovascularization of the iris. An experimental model in cats. Invest. Ophthalmol. Vis. Sci. 25:361, 1984. 3. Uno, T., Sato, M., Danjo. S., Emi, K., Ikeda, T., and Tano, Y.: Rubeosis iridis following retinal detachment surgery. [pn, Rev. Clin. Ophthalmol. 84:196, 1990. 4. Bonnet, M.: Peripheral neovascularization complicating rhegmatogenous retinal detachments of long duration. Graefes Arch. Clin. Exp. Ophthalmol. 225:59, 1987. 5. Cunha-Vaz, J. G., Fonseca, J. R., and Vieira, R.: Retinal blood flow in retinal detachment. Mod. Probl. Ophthalmol. 20:89, 1979. 6. Yoshihara, M.: Clinical studies on fundus changes and hemodynamics in degenerative myopes. Acta Soc. Ophthalmol. [pn. 82:610, 1978. 7. Yoshida, A., Hirokawa. H., Fukui, Y., and Sakamoto, J.: Choroidal circulatory changes after scleral buckling procedures. Acta Soc. Ophthalmol. [pn. 92:610,1988. 8. Aim, A., and Bill, A.: Blood flow and oxygen extraction in the cat uvea at normal and high intraocular pressures. Acta Physiol. Scand. 80:19, 1970. 9. Takahashi, S.: Studies on choroidal blood flow using the hydrogen clearance method. III. Effects of vortex vein occlusion. Folia Ophthalmol. Jpn. 33:958, 1982. 10. Hayreh, S. S., and Baines, J. A. B.: Occlusion of the posterior ciliary artery. I. Effects on choroidal circulation. Br. J. Ophthalmol. 56:719,1972. 11. Brown, G. c., Magargal, 1. E., Simeone, F. A., Goldberg, R. E., Federman, J. 1., and Benson, W. E.: Arterial obstruction and ocular neovascularization. Ophthalmology 89:139,1982.

Neovascularization of the iris in rhegmatogenous retinal detachment.

To identify conditions associated with neovascularization of the iris in rhegmatogenous retinal detachment, we examined 36 eyes with this disorder see...
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