Journal of Neuro-Ophthalmology, March 1994, Volume 14, Issue 1

Retrobulbar ischemic optic neuropathy associated with sickle cell disease.

A 52-year-old black man with a history of sickle cell SS disease presented with sudden loss of vision in his right eye. Examination of the right eye revealed no light perception and an amaurotic pupil, but an otherwise normal neuro-ophthalmic examination. On initial presentation, there was no evidence of an acute vascular event on funduscopy. Computed tomography failed to demonstrate pathology of the brain or orbit. Repeat fundus examination, 2 weeks later, still failed to demonstrate retinal or optic nerve disease. However, optic nerve pallor and central cupping became evident after 2 months and continued to progress in the ensuing year. Magnetic resonance imaging performed at that time did not disclose the presence of demyelinating disease, or aneurysmal dilation of the carotid or ophthalmic artery. A diagnosis of retrobulbar ischemic optic neuropathy is considered likely in this patient. The association of retrobulbar ischemic optic neuropathy and sickle cell anemia has not been previously reported.

Journal of Neuro- Ophthalmology 14( 1): 45^ 18, 1994. © 1994 Raven Press, Ltd., New York Retrobulbar Ischemic Optic Neuropathy Associated with Sickle Cell Disease Jay I. Perlman, M. D., Ph. D., Scott Forman, M. D., and Eulogio R. Gonzalez, M. D., Ph. D. A 52- year- old black man with a history of sickle cell SS disease presented with sudden loss of vision in his right eye. Examination of the right eye revealed no light per­ception and an amaurotic pupil, but an otherwise nor­mal neuro- ophthalmic examination. On initial presenta­tion, there was no evidence of an acute vascular event on funduscopy. Computed tomography failed to dem­onstrate pathology of the brain or orbit. Repeat fundus examination, 2 weeks later, still failed to demonstrate retinal or optic nerve disease. However, optic nerve pal­lor and central cupping became evident after 2 months and continued to progress in the ensuing year. Magnetic resonance imaging performed at that time did not dis­close the presence of demyelinating disease, or aneurys­mal dilation of the carotid or ophthalmic artery. A diag­nosis of retrobulbar ischemic optic neuropathy is con­sidered likely in this patient. The association of retrobulbar ischemic optic neuropathy and sickle cell anemia has not been previously reported. Key Words: Retrobulbar ischemic optic neuropathy- Posterior ischemic optic neuropathy- Anterior ischemic optic neuropathy- Sickle cell disease- Vaso- occlusion. From the Bronx- Lebanon Hospital Center, Department of Ophthalmology, Bronx, New York, U. S. A. Address correspondence and reprint requests to Dr. Scott Forman, Department of Ophthalmology and Neurology, West­chester County Medical Center, Valhalla, New York 10595, U. S. A. Retrobulbar or posterior ischemic optic neurop­athy has been described in association with sys­temic lupus erythematosus vasculitis ( 1), giant cell arteritis ( 1,2), presumed atherosclerosis ( 3), ipsilat-eral internal carotid artery occlusion ( 4), and herpes zoster ophthalmicus ( 5). Rizzo and Lessell ( 6) reported two cases of bilateral posterior isch­emic optic neuropathy during general surgery; the etiology was presumed to be secondary to in­duced, profound systemic hypotension and ane­mia during surgical procedures. We present a pa­tient with sickle cell disease with sudden loss of vision in his right eye and a normal neuro-ophthalmic examination diagnosed as retrobulbar ischemic optic neuropathy. CASE REPORT A 52- year- old black man with a history of sickle cell SS disease and common migraine presented to the emergency room at Bronx- Lebanon Hospital Center complaining of right- sided retro- orbital headache and sinus pain without fever; he was treated for a presumed sinusitis with pseudoephe-drine, amoxicillin, and Tylenol, and discharged. Five days later, he returned to the emergency room with a complaint of sudden painless loss of vision in his right eye upon awakening that morn­ing. He had noted blurred vision in his right eye after an afternoon nap the day before, but attrib­uted this to the medication, and discontinued all medicines. Upon awakening the next morning with no vision in the same eye, he sought medical attention. The patient denied any accompanying headache or any other abnormal neurologic or vi­sual symptoms. His last sickle crisis was 7 years previously. Uncorrected visual acuity was NLP OD and 20/ 30 + 2 OS. An amaurotic pupil was noted in the 45 46 ]. I. PERLMAN ET AE. right eye. External eye examination and applana­tion tonometry was normal. Slit- lamp examination revealed comma- shaped conjunctival vessels of the inferior bulbar conjunctiva in both eyes. Fun-duscopic examination demonstrated optic disc cupping of 40% OD and 30% OS with moderate central excavation bilaterally. Neurologic examina­tion was unremarkable. The patient was afebrile and normotensive with a pulse of 58. Systemic ex­amination was significant for occasional premature ventricular beats and a II/ VI diastolic murmur. Emergent computed tomography scan revealed bilateral maxillary, sphenoid, and ethmoid sinus opacification, more prominent on the right, with no evidence of orbital or intracranial hemorrhage or mass ( Fig. 1). Laboratory findings were signifi­cant for a hematocrit of 22.5 and an erythrocyte sedimentation rate of 49. Intravenous fluids and antibiotics were admin­istered along with 100 mg oral prednisone daily. The patient received an exchange transfusion ex­change transfusion of 2 units packed red blood cells. At 4 days posttransfusion the hematocrit was 32.2. Right temporal artery biopsy was interpreted as normal, and steroid therapy was gradually ta­pered. Repeat orbital computed tomography re­vealed partial resolution of sinus opacification and funduscopy remained unremarkable on discharge. Fundus photography performed 2 weeks later revealed mild narrowing or spasm of the primary arterioles ( Fig. 2). However, fluorescein angiogra­phy was unremarkable with no evidence of de­layed arteriolar filling. A normal Goldmann visual field was obtained from the left eye. Fundus pho- FIG. 1. Computed tomography of the orbit and si­nuses. tography, 2 months after discharge, demonstrated deepening and enlargement of the right optic cup to 60% with central pallor. Magnetic resonance im­aging showed no evidence of demyelinating plaques, intracranial hemorrhage, or aneurysmal dilation of the carotid or ophthalmic arteries. An­giography to rule out an ophthalmic artery aneu­rysm was considered, but the risk of precipitating a vaso- occlusive process in a sickle cell patient was considered unacceptable. A pattern visual evoked potential ( VEP) of the right eye demonstrated poorly formed but repro­ducible responses to 56- and 28- second checks; the latency of the former was at the upper end of the normal range while the latter was abnormally de­layed. No reproducible VEP was present following 14- second check stimulation. The VEP response OS demonstrated normal latencies and amplitudes for all stimulus conditions. The results were inter­preted as being consistent with an optic nerve ab­normality anterior to the chiasm on the right. Optic disc cupping and pallor continued to pro­gress, and fundus photography 14 months post-discharge revealed moderate to severe central pal­lor ( Fig. 3). DISCUSSION The present case is unusual because of the ab­sence of significant fundus findings for 2 months following initial visual loss. Initial ocular examina­tion showed a surprising absence of retinal or optic nerve pathology. Disc edema was not observed at any time, with delayed optic atrophy the only manifestation of the patient's sudden and com­plete visual loss in the right eye. Computed to­mography and magnetic resonance imaging pro­vided no evidence for a compressive or demyelin­ating etiology. The diagnosis of retrobulbar or posterior ischemic optic neuropathy is warranted in this case of sudden unilateral visual loss and progressive optic disc pallor and atrophy. To our knowledge, this is the first reported case of posterior ischemic optic neuropathy in a patient with sickle cell disease. Posterior ischemic optic neuropathy is separate and distinct from the more common entity, anterior ischemic optic neuropa­thy, and is associated with acute visual loss and an afferent pupil in the absence of acute disc pathol­ogy. This can occur because of the separate and distinct arterial supplies of the anterior and poste­rior portions of the optic nerve, with the latter sup­plied by independent collaterals of the ophthalmic artery. Therefore, ischemia to the posterior part of the optic nerve would result in a normal- appearing / Nnuro- Ophthalmol, Vol. 14, No. 1, 1994 OPTIC NEUROPATHY AND SICKLE CELL DISEASE 47 FIG. 2. Optic nerve of right eye 2 weeks after initial presentation. disc during the acute phase with subsequent de­scending optic atrophy. Acute vaso- occlusive events are common sys­temic manifestations of sickle cell disease, and the eye is no exception. Although vaso- occlusive dis­ease of the retina and choroid have been reported ( 7,8), optic nerve involvement in sickle cell disease is rare indeed. Transient vaso- occlusive changes of the small capillary and precapillary arterioles of the disc may occur without visual acuity effects ( 9). Slavin and Barondes ( 10) reported a case of ante­rior ischemic optic neuropathy in a patient with hemoglobin SC disease, resulting in severe unilat­eral visual loss. In that case, fluorescein angiogra­phy performed 1 month after onset of visual loss demonstrated pallid ischemic disc edema bilater­ally, and narrowed retinal arterioles. The underlying etiology of the presumed isch­emic event in this patient is confounded by several components of the patient's history. Anterior isch­emic optic neuropathy has been reported in asso­ciation with ocular migraine ( 11). In this case, how­ever, the patient denied any pain, headache, or other migrainous symptoms associated with his sudden visual loss. Acute sinusitis has not been reported in association with ischemic optic neu­ropathy, but a relation to optic neuritis has been suggested ( 12). Despite the presence of sinus dis­ease in this patient, neuroimaging demonstrated no evidence of orbital extension. Although un­likely, use of the vasoconstrictor, pseudoephe-drine, may have played a role in the vaso- occlusive event. The vasoconstriction induced by pseu-doephedrine may have triggered focal ischemia, thereby precipitating the onset of a sickle crisis. Despite these complicating factors, we believe FIG. 3. Optic nerve of right eye at 14 months with marked central pallor and progressive enlargement and deepen­ing of the optic cup. J Neuro- Ophthalmol, Vol. 14, No. 1, 1994 48 J. I. PERLMAN ET AE. this case represents a retrobulbar ischemic optic neuropathy secondary to sickle cell vaso- occlusion of the circulation to the retrolaminar portion of the optic nerve. REFERENCES 1. Hayreh SS. Posterior ischemic optic neuropathy. 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