| Identifier |
Transient_Monocular_Blindness_guest_lecture |
| Title |
Transient Monocular Blindness (Guest Lecture) |
| Creator |
Shirley H. Wray, MD, PhD, FRCP |
| Affiliation |
(SHW) Professor of Neurology, Harvard Medical School; Director, Unit for Neurovisual Disorders, Massachusetts General Hospital, Boston, Massachusetts |
| Subject |
Sunlight Provoked Transient Monocular Blindness; Low Pressure Retinopathy; Ipsilateral Internal and External Carotid Occlusive Disease; Ischemic Eye Syndrome; Retinal Stroke; Transient; Transient Visual Loss; Ocular Ischemic Syndrome |
| History |
The patient is a 61 year old lawyer who carried a diagnoses of late onset diabetes mellitus, hypertension, hyperlipidemia, and glaucoma. He presented with transient blurred vision in his left eye (OS) In June 1989 whilst standing in the intense sunlight in the parking lot of a shopping mall, the patient noted blurred vision in the left eye, described as a generalized haze. He had never had an episode like this before. He left the parking lot and went into a shop. Whilst inside, his vision OS returned to normal. As soon as he went back outside into bright sunlight to get into his car, blurred vision OS returned and persisted for as long as he was in the sun. Inside his car, his vision returned to normal. He could look through the wind screen at the sunshine outside without a reoccurrence of monocular blurred vision OS. In the next few weeks however he had several more sunlight provoked visual episodes OS lasting for 5 to 10 minutes. The attacks were not accompanied by photopsias, or a loss of vision described as a shade coming down or a blind going across his visual field. On careful inquiry he denied any visual symptoms to suggest impaired contrast vision such as a bright white sheet of paper dazzling his vision and impairing reading, or blurring watching a bright television screen. He had no symptoms in the right eye. Symptomatic inquiry was negative for symptoms suggestive of a cerebral transient ischemic attack including speech impairment, diplopia, vertigo, weakness in the limbs or any sensory disturbance. Past History: Negative for cardiac disease or arrhythmia. Family History: Positive for diabetes and hypertension. Social History: Heavy pipe smoker in the past until 1985 and a heavy drinker over the period of his divorce in 1982. The patient consulted a neurologist on the Cape because he felt that "something was wrong". He was referred to Boston for evaluation. The neurovisual examination documented: Visual acuity OD 20/25, J1; OS 20/30, J1. Color vision intact and Goldmann visual fields full OU. Pupils equal and brisk to light and near Markedly dilated episcleral vessels OU with no rubeosis iridis Normal intraocular pressures Eye movements full with no nystagmus No ocular, carotid or cardiac bruits. BP 150/80 right arm and left, pulse 82 regular Dilated fundus examination showed: • OD: optic disc normal • OS: retinal arteries slight attenuated • Neovascular changes of the optic nerve head • Multiple dot and flame-shaped intraretinal hemorrhages. • Dilated tortuous retinal veins varying in caliber. Signs consistent with the diagnosis of a low pressure retinopathy. (see attached PPP) Pulsation of the branches central retinal artery on the surface of the left optic disc were easily elicited by gentle finger pressure on the globe indicating a very low retinal diastolic pressure. A diagnosis of the Ocular Ischemic Syndrome OS was made. Occlusive disease of the ipsilateral left internal carotid artery (ICA) and external carotid artery (ECA) was suspected. Carotid non-invasive test showed: 1. Occlusion of the left ICA associated with reversal of flow in the ophthalmic artery. 2. Moderate right ICA stenosis 3. Bilateral ECA stenosis 4. Collateral flow from right to left anterior cerebral arteries Three vessel angiography: Right common carotid arterial (CCA) injection showed: • Atheromatous irregularity and narrowing of the ICA origin intraluminal diameter 4.0 mm. • High grade stenosis of the origin of the ECA • Cross filling of the left middle CA from the right CCA injection representing a significant gradiant occlusion in the left carotid system • A choroidal blush, right globe, seen at 4.5 seconds. Right ophthalmic artery normal. The left CCA injection: • Complete occlusion of the left ICA at its origin • No flow demonstrated within the intracranial portion of the left ICA • Minimal stenosis of the origin of the ECA • Extensive collateral reconstitution of the supraorbital, supraocular orbital vessels with retrograde reconstitution of the left proximal ophthalmic artery and cavernous carotid. Normal flow demonstrated in both vertebral arteries and the basilar artery. Electroretinogram showed: A normal ERG OD Reduced and delayed cone ERG OS Impression: Light sensitivity OS appears related to cone dysfunction which in turn may be related to ischemia. Brain MRI showed: Scattered foci of T2 high-signal in the subcortical and periventricular white matter consistent with microangiopathic disease. The patient was not a candidate for carotid or temporal artery to middle CA bypass surgery. Medications: 1. Coumadin 2. Micronase and Glucophage to control his diabetes 3. Timoptic and Propine eye drops to lower intraocular pressure. In 1993 VA OD 20/25, OS 20/80. Fundus examination now showed: Mild background diabetic retinopathy OD A dense vitreous hemorrhage OS Ophthalmic Procedures: In 1993, panretinal photo-coagulation OS, stabilized VA OS 20/70 until 1995. In 1995, a recurrent vitreous hemorrhage reduced VA OS to light perception only. Vitrectomy was recommended but he moved to Florida prior to surgery and was lost to follow-up. |
| Anatomy |
Occlusive internal and external carotid disease ipsilateral to the symptomatic ischemic eye. |
| Pathology |
The Ocular Ischemic Syndrome is a progressive disorder that results from hypoperfusion of the eye. Kearns and Hollenhorst first reported the syndrome and introduced the term venous stasis retinopathy (3). The syndrome usually occurs in individuals older than 50 years of age and may extend into their 70's and 80's. Men are more frequently affected than women, and there is no racial preference. Most cases are known to be unilateral, although bilateral cases can occur. Transient monocular blindness is the most common ocular symptom of carotid disease. The most common symptom of the ocular ischemic syndrome is visual loss which may occur acutely or may develop slowly over a period of days to months. Visual acuity can range from 20/20 to 20/400, depending on the extent of involvement. Pain may be one of the earliest symptoms, with pain being located over an eye and sometimes radiating to the temporal portion of the skull. One of the commonest signs associated with the ocular ischemic syndrome is rubeosis iridis. The appearance of rubeosis iridis in patients who are not diabetic may be a sign that the ocular ischemic syndrome is present. As a result, neovascular glaucoma can occur in this condition; however, frequently neovascularization of the iris can occur without significant elevation of the intraocular pressure. |
| Disease/Diagnosis |
Ocular Ischemic Syndrome with occlusive ipsilateral carotid disease |
| Clinical |
This 61 year old patient describes in detail his first attack of transient monocular blurring (TMB) of vision in the left eye. It occurred: • On moving from a darkened area into a brightly lighted area - i.e. from a car into sunlight. • Attacks of TMB happened almost every time in bright light, not necessarily sunlight • "Blurring" was as a generalized haziness, like a film of vaseline over the eye • No dazzle looking at bright white magazine pages • Color vision intact • Duration: As long as he stayed in bright light. Vision recovered completely in normal light.. In 1979, Furlan et al reported the phenomenon of unilateral loss of vision, causing things to appear bleached like a photographic negative, in patients exposed to bright sunlight (2). On examination all the patients had decreased retinal artery pressure in the symptomatic eye and a high-grade stenosis or occlusion of the ipsilateral internal carotid artery. Attenuation of the visual evoked response immediately after exposure to bright light was subsequently demonstrated in four such patients but not in controls (1). A similar phenomenon of unilateral loss of vision induced by white light has also been recognized in patients with ipsilateral carotid occlusive disease (4). Light exposure may also induce episodic bilateral visual impairment in patients with high-grade stenosis or occlusion of both internal carotid arteries (5). The visual symptoms consist of blurring, dimming or scotomata in both eyes (never a shade of blind effect). The symptoms persist for as long as the patient is exposed to bright light and for seconds to hours after the exposure. Visual loss in bright or white light is considered to represent macular dysfunction as a result of retinal ischemia from reduced choroidal (choriocapillaris) blood flow causing a delay in the regeneration of visual pigments in the retinal pigment epithelial layer. Comment: Transient monocular blindness (TMB) is a herald symptom of stroke to the brain and/or eye. There are four types of monocular TMB: • TMB Type I due to transient retinal ischemia • TMB Type II due to retinal vascular insufficiency • TMB Type III due to transient angiospasm • TMB Type IV idiopathic and/or associated with anticardiolipid antibodies TMB Type I is one variety of carotid artery distribution transient ischemic attack (TIA) which requires emergency treatment. It is essential to take a meticulous history of the attack documenting onset, duration, frequency, activity of the person at the time, and speed and completeness of recovery of vision. What to look for funduscopically after dilation of the pupil must include: • Retinal emboli • Branch retinal artery occlusion •  visible embolus • Retinal infarct •  cytoid body • Venous stasis retinopathy • Asymmetric hypertensive retinopathy • A low diastolic ophthalmic artery pressure • Ischemic disc swelling (anterior ischemic optic neuropathy) Attached to this case is a PowerPoint Presentation showing fundus photographs, 3-vessel angiogram images and a unique film, made by Dr. Cogan, of microemboli shooting rapidly along branches of the central retinal artery. The fundus photographs show both early and late stages of low pressure retinopathy coupled with a photograph of rubeosis iridis. For complete review see Wray SH. (6). |
| Presenting Symptom |
Blurred Vision |
| Ocular Movements |
Normal |
| Neuroimaging |
Brain MRI: T2 hyperintense foci consistent with microvascular disease, negative for silent embolic infarcts. |
| Treatment |
Internal and/or external ipsilateral carotid endarterectomy when possible. |
| Etiology |
Severe occlusive carotid disease. |
| References |
1. Donnan GA. Sharbrough EW and Whisnant JP. Carotid occlusive disease: effect of bright light on visual evoked response. Arch of Neurol 1982, 39:687-689. http://www.ncbi.nlm.nih.gov/pubmed/7125996 2. Furlan AJ, Whisnant JP and Kearns TP. Unilateral visual loss in bright light: an unusual symptom of carotid artery occlusive disease. Arch of Neurol 1979, 36:675-676. http://www.ncbi.nlm.nih.gov/pubmed/508123 3. Kearns TP, Hollenhorst RW. Venous stasis retinopathy of occlusive disease of the carotid artery. Mayo Clin Proc 1963, 38:304-312. http://www.ncbi.nlm.nih.gov/pubmed/14043286 4. Sempere AP, Duarte J, Coria F and Claveria LE. Loss of vision by the colour white: a sign of carotid occlusive disease. Stroke 1992;23:1179. http://www.ncbi.nlm.nih.gov/pubmed/1636195 5. Wiebers DO, Swanson JW, Cascino TL and Whisnant JP. Bilateral loss of vision in bright light. Stroke 1989, 20:554-558. http://www.ncbi.nlm.nih.gov/pubmed/2929033 6. Wray SH. Visual Symptoms. In: Bogousslavsky J and Caplan LR eds. Stroke Syndrome. Cambridge University Press 2001,1:111-128. |
| Language |
eng |
| Format |
application/pdf |
| Format Creation |
Microsoft PowerPoint |
| Type |
Text |
| Relation is Part of |
937-2; 016-1 |
| Collection |
Neuro-Ophthalmology Virtual Education Library: Shirley H. Wray Collection: https://novel.utah.edu/Wray/ |
| Publisher |
North American Neuro-Ophthalmology Society |
| Holding Institution |
Spencer S. Eccles Health Sciences Library, University of Utah |
| Rights Management |
Copyright 2002. For further information regarding the rights to this collection, please visit: https://NOVEL.utah.edu/about/copyright |
| ARK |
ark:/87278/s6x7cd4n |
| Setname |
ehsl_novel_shw |
| ID |
2174243 |
| Reference URL |
https://collections.lib.utah.edu/ark:/87278/s6x7cd4n |
