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Show / ollnw[ of CIi" i,,, 1 NCllro- 0l'htlw["", It, SY 9( 3): 20( l-- 2V4, 1989. Anterior Segment Ischemia Secondary to Carotid Occlusive Disease Richard P. Mills, M. D. © 1989 Raven Press. Ltd.• New York The ischemic signs of carotid occlusive disease in the anterior segment can be summarized as follows: vasodilation in the conjunctiva, episclera, and iris; neovascularization in the iris and the anterior chamber angle with consequent neovascular glaucoma. with or without elevation of intraocular pressure; and noninflammatory uveitis with corneal edema, keratitic precipitates, flare and cells in the anterior chamber, and late development of cataract. A questionnaire was sent to neuro- ophthalmology and glaucoma specialists regarding their perceptions of this condition. On average, approximately 1 case per specialist per year was seen. One third of the respondents had seen significant ocular pressure increase in patients with rubeosis follOWing successful vascular surgery. Most felt that pametinal photocoagulation, though not as effective as in diabetic rubeosis, did cause regression of iris and angle neovascularization. The visual prognosis following all types of treatment was not good and was insufficient to justify a clear recommendation about the advisability of aggressive management of this condition. Key Words: Carotid- Carotid endarterectomyConjunctivitis- Extracranial- intracranial bypassIntraocular pressure- Neovascular glaucoma- Ocular ischemia- Panretinal photocoagulation- UveitisVascular surgery. From the Department of Ophthalmology. University of Washington, Seattle. Washington Presented at an annual meeting of the American Academy of Ophthalmology. Dallas. Texas, November 1987 Address ( orreSpond,' n r ,-, , md HTrint requests tll Department ,,( <) r, hth;, JrT" , I, :( 1- JlI, Un;\",,,; tv ,) 1 Washington, Seattle. 200 Carotid occlusive disease most commonly occurs without any ocular manifestations. Only in a small percentage of cases of carotid occlusion ( 1,2) do ischemic signs of the ipsilateral anterior segment develop. Unfortunately, none of these signs are pathognomonic; each may be attributed to a different condition, and so, mistakes in diagnosis are easy to make. SIGNS AND SYMPTOMS Our knowledge of the spectrum of anterior segment ischemic signs ( Table 1) has been refined by many observers ( 2- 6) since the original reports of Kearns and Hollenhorst ( 7) and Knox ( 8). Conjunctiva and Episclera Within conjunctiva and episclera, the eye usually becomes red. The redness often occurs in a pattern resembling a ciliary flush, and large dilated veins may appear, as are seen in patients with dural arteriovenous malformations of the cavernous sinus. The nonspecific redness may prompt ineffective treatment for conjunctivitis before the true cause is discovered. Pupil The pupil may show a sluggish reaction to light because of sphincter ischemia or neovascular proliferation on the iris surface. A relative afferent pupillary defect may signal significant retinal ischemia and reduced visual function. Given the hemorrhages in the fundus, the condition may be incorrectly interpreted as an ischemic central retinal vein occlusion. The cornea may become edematous ( even though the intraocular pressure is normal) because of ischemia, resulting in a hazy fundus view. ANTERIOR SEGMENT ISCHEMIA 201 SURVEY TABLE 2. Risk factors for neovascular glaucoma As few ophthalmologists have seen more than a handful of patients with anterior segment ischemia Lens Rarely seen initially, but commonly encountered as a late finding, is cataract. 32.0% 36.9% 13.0% 1.5% 14.0% 8.0% Brown et al. ( 11) 208 cases 33.0% 28.0% 8.0% 11.0% 3.0% 17.0% Hoskins ( 12) Risk factor 100 cases Diabetic retinopathy Central retinal vein occlusion Carotid occlusive disease Uveitis Other retinal vascular disease Miscellaneous or unknown evidence of 360 degrees of peripheral anterior synechiae, intraocular pressures are frequently within the normal range. In Brown and Magargal's latest series of 43 patients with the ocular ischemic syndrome, two- thirds of whom had rubeosis iridis, only one- third had intraocular pressure over 22 mm Hg ( 6). Apparently, aqueous production and outflow are both decreased, so intraocular pressures may not stray into the abnormal range ( 6,10,13). Despite the normal intraocular pressure, spontaneous retinal artery pulsations may be observed, and axonal damage resulting in glaucomatous optic disc changes may ensue. Only after restoration of more normal arterial pressure ( after vascular surgery) does aqueous production normalize and the outflow obstruction become manifest by markedly increased intraocular pressure ( 2,14- 16). It is generally agreed that the development of neovascular glaucoma in carotid occlusive disease is a poor prognostic sign. Aggressive treatment, including panretinal photocoagulation to reduce the ischemic stimulus, vascular surgery to improve flow, and medical and surgical glaucoma procedures to control intraocular pressures, offers the only chance for salvage of the eye ( 17). Anterior Chamber Ischemic uveitis, present in 18% of eyes with the ocular ischemic syndrome, as reported by Brown and Magargal ( 6), is characteristically unresponsive to steroid medication. Cells are common in the anterior chamber, but not in the vitreous. Posterior synechiae can result. Spontaneous hyphema may result ( 18). Iris and Chamber Angle TABLE 1. Anterior segment ischemic signs secondary to carotid occlusive disease Conjunctiva and episclera Injection Ciliary flush Prominent large vessels Pupil Sluggish reaction to light Relative afferent pupillary defect Cornea Edema ( even with normal lOP) Iris and anterior chamber angle Dilated vessels Rubeosis iridis Neovascular glaucoma Anterior chamber Flare and cells Spontaneous hyphema Lens Cataract The most serious of the anterior segment complications of carotid occlusive disease is the development of rubeosis iridis, with or without neovascular glaucoma. One must be careful to insure that the prominent iris vessels are truly neovascular, as the normal iris vessels may become dilated, along with those in the conjunctiva and episclera, in response to ischemia. The rubeosis is frequently evident at the pupillary margin and in the anterior chamber angle, and is indistinguishable from that seen in diabetes. However, the rubeosis seen in diabetes almost always occurs in patients with proliferative retinopathy. Therefore, diabetics without proliferative retinopathy, who present with rubeosis, should be investigated for carotid occlusive disease ( 9- 11). When severe bilateral carotid disease is present, a striking appearance of bilateral rubeosis may result. Review of a series of cases of rubeosis iridis published by Brown et al. ( 11) and Hoskins ( 12) may help place the risk factor of car~ tid o~ clusi. ve disease in proper perspective. ProlIferative diabetic retinopathy and central retinal vein occlusi~ n each were found in about one- third of the cases In each series ( Table 2). The different percentages for uveitis, carotid occlusive disease, and other retinal vascular disease probably reflected the different practice profiles of the authors: one limited to glaucoma and the other devoted to retinal disease. Rubeosis iridis is commonly associated with elevated intraocular pressure and optic nerve damage of glaucoma. However, in the rubeosis associated with carotid occlusive disease, the glaucoma is unusual, in that only one- third of patients have elevated intraocular pressure. Despite gonioscopic I Clin Neuro- ophthalmol, Vol. 9, No. 3, 1989 202 R. P. MILLS IJJ 60 0 :: E '. C0.1.> - 10 . c E~ z ~ o 80 ,.--------------------, 3: 1 3: 1 to 10: 1 10: 1 to 100: 1 ?? FIG. 3. Responses of ANGLE members to questionnaire item 1b. 1: 1 3: 1 10: 1 ?? FIG. 2. Responses of Frank Walsh Society members to questionnaire item 1a. o Response to Treatment Two additional questions dealt with response to treatment, so it was felt advisable to count responses only from those 92 respondents who saw at least one such patient a year. As the proportions 30.-------------------, ~ 20 :: E ' 0... C1> . c E 10 ~ Z Frequency The neuro- ophthalmologists were asked to estimate the relative frequency of posterior to anterior segment signs of carotid occlusion seen in their practice. The perceived incidence among neuroophthalmologists was in the range of 3: 1- 10: 1 ( Fig. 2). The glaucoma specialists were asked to estimate the relative frequency of diabetic rubeosis and rubeosis due to carotid occlusive disease. Most believed it to be between 10: 1 and 100: 1 ( Fig. 3). Thirty percent of the neuro- ophthalmologists and 38% of the glaucoma specialists recalled having seen patients with significant intraocular pressure rise following carotid endarterectomy ( Table 3). Scope One hundred eleven members of the Frank Walsh Society, and 224 physician members of ANGLE received questionnaires; 47 ( 42%) of the former and 109 ( 48%) of the latter completed them. A total of 138 cases were reported by the neuroophthalmologists, and 466 were reported by the glaucoma specialists. The mean estimate of the number of cases of rubeosis secondary to carotid occlusive disease per responding physician per year was only 1 among the neuro- ophthalmologists and only 1.4 among the glaucoma specialists. Interestingly, rubeosis was bilateral in 118 cases ( 20%). related to carotid occlusive disease, the author polled ophthalmologists specializing in neuroophthalmology and glaucoma- the two disciplines most likely to see such patients. A brief questionnaire was devised ( Fig. 1), recognizing the severe limitations on the interpretation of such data, in an effort to discover the perceptions of ophthalmic specialists about this condition. 1a. ( To Frank Walsh members) In your practice, about what ratio of posterior segment ( venous stasis retinopathy) to anterior segment ( rubeosis, etc.) complications of carotid occlusive disease have you seen? 1b. ( To ANGLE members) In your practice, rubeosis due to diabetes and rubeosis due to carotid occlusive disease occur in what ratio? 2. Estimate the number of cases of rubeosis secondary to carotid occlusive disease you have seen in the last 3 years. 3. What percentage of those were bilateral? 4. Have you had patients who experienced significant lOP rise following enderterectomy as inflow improves, while outflow remains impaired from angle neovascularization? 5. What is your opinion of panretinal photocoagulation in the management of rubeosis secondary to carotid diseae ( check one) __ works as well as in diabetic cases in inducing regression of rubeosis __ works, but not as reliably as in diabetics __ seldom causes regression of rubeosis without reestablishing carotid flow. 6. What is the prognosis for vision following all indicated treatment ( PRP, endarterectomy, cyclocryo, etc.)? ( check one) __ no improvement generally __ modest improvement __ dramatic improvement __ generally continues to deteriorate I Gin NeuTo- ophthalmol, Vol. 9, No. 3, 1989 ANTERIOR SEGMENT ISCHEMIA 203 TABLE 3. Have you seen significant lOP rise in patients with rubeosis following endarterectomy? TABLE 5. What is the usual visual prognosis following all indicated treatment in these patients? Yes No No answer Frank Walsh ( n = 47) 30% 45% 25% ANGLE ( n = 109) 38% 34% 28% 3%- Dramatic improvement 24%- Modest improvement 34%- No improvement 22%- Continues to deteriorate 17%- No opinion n = 92 respondents seeing > 1 case per year. were similar among the two specialty groups, the responses were pooled. Most felt that pametinal photocoagulation to reduce the ischemic stimulus for iris neovascularization was effective, but not as effective as for diabetic neovascularization ( Table 4). Prognosis The usual visual prognosis following all indicated treatment, including pametinal photocoagulation, vascular surgery of endarterectormy or extracranial to intracranial bypass surgery, and glaucoma procedures, was not optimistic ( Table 5). The median response was no improvement. Equal numbers of respondents showed modest improvement and continued deterioration, whereas only a few indicated dramatic improvement. DISCUSSION The anterior segment complications of carotid occlusive disease are uncommon. In fact, among glaucoma and neuroophthalmic specialists, about 1 case per year on average was seen. Although the literature indicates a ratio of about 2: 1 posterior: anterior segment signs of carotid occlusion, the respondents to the questionnaire indicated a ratio in the range of 3: 1- 10: 1. This could represent an underreporting because of greater awareness of the posterior segment changes among the neuroophthalmologists, but the complication of rubeosls iridis with neovascular glaucoma is sufficiently devastating that it is not likely to be overlooked with great frequency. It could also be explained by an underestimate of frequency, as the questionnaire was asking only for perceptions, not verified data. Published series ( 11,12) indicate that the ratio of TABLE 4. Panretinal photocoagulation in rubeosis secondary to carotid occlusive disease 9%- Works as well as in diabetic patients 48%- Works, but not as reliably . 23%- Seldom works without carotid surgery 20%- No opinion n = 92 respondents seeing> 1 case per year. diabetic rubeosis to rubeosis of carotid occlusive disease is in the range of 2: 1- 5: 1. The glaucoma specialists perceived the ratio as much higher, in the range of 10: 1- 100: 1. This may represent a difference in the severity of the intraocular pressure ( lOP) increase in the two conditions, which cause diabetic eyes with the higher lOP to be referred for glaucoma management, or again, it might represent an inaccurate perception, as no retrospective patient analysis was performed. If rubeosis is present with a normal intraocular pressure, a pressure rise may occur following successful vascular surgery, a phenomenon common enough to have been seen by one- third of the questionnaire respondents. Pametinal photocoagulation ( PRP) was perceived as effective in treating rubeosis associated with carotid occlusion, though somewhat less so than in diabetes. Prior reports have indicated that PRP has been at least partially effective in reducing iris neovascularization ( 13,15,19,20). If intraocular pressure is even slightly elevated, optic nerve perfusion is endangered, so attempts should be made to control it. Occasional case reports have appeared showing dramatic improvement following endarterectomy or extracranialintracranial bypass surgery ( 21- 23), but successful treatment is not often associated with significant visual improvement ( 18). In a series of 14 patients with ocular ischemic syndrome treated aggressively, Scimeca et a!' ( 17) reported that only 2 showed visual improvement of 2 Snellen lines or more, though only one patient ( who had refused carotid surgery) required enucleation. Questionnaire respondents agreed, indicating that aggressive treatment, including pametinal photocoagulation, inhibitors of platelet aggregation, vascular surgery, and glaucoma procedures on average did not result in visual improvement. Acknowledgments: The author is grateful to the individual members of the Frank Walsh Society and the Associated North American Glaucomatologist Learning Ensemble ( ANGLE) for completing the questionnaire and offering comment. This investigation was supported in part by an unrestricted grant from Research to Prevent Blindness, Inc. / Clill Neuro- ophthalrnol, Vol. 9, No. 3, 1989 204 R. P. MILLS REFERENCES 1. Keams IP. Ophthalmology and the carotid artery. Am J OphthalmoI1979; 88: 714. 2. Young LHY, Appen RE. Ischemic oculopathy- a manifestation of carotid artery disease. Arch NeuroI1981; 38: 358. 3. Cowan CL, Butler G. Ischemic oculopathy. Ann Ophthalmol 1983; 15: 1052. 4. Brown Gc, Magargal LE, Simeone FA, Goldberg RE, Fedennan JL, Benson WE. Arterial obstruction and ocular neovascularization. Ophthalmology 1982; 89: 139. 5. Sturrock GO, Mueller HR. Chronic ocular ischemia. Br J Ophthalmol 1984; 68: 716. 6. Brown Gc, Magargal LE. Ihe ocular ischemic syndromeclinical, fluorescein angiographic and carotid angiographic features. Int Ophthalmol ( in press). 7. Keams IP, Hollenhorst RW. Venous stasis retinopathy of occlusive disease of the carotid artery. Proc Staff Meet Mayo Clinic 1963; 38: 304. 8. Knox DL. 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