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Woman presents with blurred vision, visual field defect
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A 64-year-old white female was referred to our clinic by her optometrist for evaluation of an edematous left optic nerve head. The patient reported blurred vision and a grey appearance to the inferior visual field of her left eye that first appeared roughly 3 weeks prior, but had not increased in severity.
The patient denied seeing any flashes of light or floaters, any pain, headache, jaw claudication or diplopia. This was the first time she had experienced these symptoms, and her ocular history was remarkable for a longstanding corneal scar in the right eye.
The patient’s medical history was unremarkable and she was a nonsmoker. The only medication she used was a 220-mg tablet of naproxen as needed. She had a positive family history of fatal valvular heart disease, stroke and hypertension.
The patient’s best corrected distance visual acuity was 20/20-1 in the right eye and 20/40+2 in the left eye. Her pupils were equal, round and reactive to light. Her left eye had a relative afferent pupillary defect (RAPD) graded with a neutral density filter at 0.3 log units. Extraocular motilities were full in both eyes, and cover testing revealed slight esophoria at 40 cm. Confrontation visual fields were full in the right eye and impaired infranasally in the left eye. Red color saturation was equal in each eye.
Fundus photo of the patient’s left optic nerve head at initial presentation shows superior sectoral edema of the optic nerve head that is obscuring the retinal vasculature.
Images: Peterson B
Humphrey 24-2 visual field of the patient’s left eye shows an absolute inferior-nasal defect.
The anterior segment showed an inferiorly located corneal scar in the right eye and 1+ nuclear sclerotic cataracts in each eye. Intraocular pressures were measured at 14 mm Hg OD and 15 mm Hg OS. Dilated fundus examination revealed crowded optic nerves with 0.0/0.0 cup-to-disc ratios. The right optic nerve head appeared healthy, with sharp margins and no edema or hemorrhaging. The left optic nerve head had superior sectoral edema, blurring the superior disc margin and obscuring the adjacent vasculature. Both maculae were flat without edema, the vitreous was normal, and the peripheral retina was unremarkable in both eyes.
A Humphrey 24-2 visual field (Carl Zeiss Meditec) was performed on each eye. The right eye result was unremarkable, showing sporadic depressions but with poor reliability. The left eye showed an absolute inferior-nasal altitudinal defect with good reliability. An optic nerve head optical coherence tomography test was performed, revealing robust nerve fiber layer in both eyes and elevation of the superior nerve fiber layer in the left eye.
The patient’s blood pressure was 158/95 mm Hg. A full blood panel was obtained that day to analyze the patient’s cholesterol level, triglycerides, high-density lipoprotein, low-density lipoprotein, erythrocyte sedimentation rate, C-reactive protein and complete blood count with platelets. The only remarkable finding from the blood panel was an elevated cholesterol level of 240 mg/dL. A computerized tomography (CT) scan of the orbit and head was ordered to rule out intracranial pathology.
The CT scan was negative for any pathology. The patient was seen by her internist 1 week later. At this appointment, her blood pressure was 132/82 mm Hg and her body mass index was 32.59. Her internist recommended she begin taking 81 mg aspirin daily and ordered an ultrasound of her carotid arteries. Her carotid ultrasound was positive for mild atherosclerotic plaques with no significant stenosis of either internal or common carotid arteries.
Brynn Peterson
At an ophthalmologic follow-up visit with us 5 weeks later, the patient’s RAPD was the same, her left visual field defect was stable, and her blood pressure was 140/82 mm Hg. The sectoral edema of her left optic nerve head had resolved, and the blood vessels were no longer obscured superiorly.
There are several differential diagnoses to consider for an adult with unilateral optic nerve head edema with an accompanying visual field defect. The most likely differentials are nonarteritic anterior ischemic optic neuropathy (NAION), arteritic anterior ischemic optic neuropathy (AAION) and optic neuritis (ON).
Nonarteritic anterior ischemic optic neuropathy
A NAION is typically characterized by acute, unilateral and painless vision loss in an individual older than 50 years. Reduction in visual acuity depends on the severity of optic nerve head ischemia. NAION is more common in individuals with small, crowded optic nerve heads and minute cup-to-disc ratios, as they are more prone to ischemic episodes due to structural crowding. Often, the optic nerve head edema is sectoral and presents with flame hemorrhages.
In the case of a longstanding NAION, the clinician should expect some degree of sectoral pallor as evidence of prior edema. In the majority of cases, it is common to have an altitudinal visual field defect in the affected eye that corresponds with optic nerve head edema. It is most commonly an inferior altitudinal defect, although superior altitudinal defects and central defects have also been regularly reported. Patient discovery of visual field loss and visual acuity reduction is most commonly identified upon waking in the morning.
Leonid Skorin Jr.
NAION is most prevalent in Caucasians. It typically presents in patients with vascular risk factors such as hypertension, nocturnal hypotension, hyperlipidemia, diabetes, obstructive sleep apnea, smoking and use of phosphodiesterase-5 inhibitors. NAION has been found to occur more commonly during the warm summer months. Vision loss is typically permanent and nonprogressive.
Arteritic anterior ischemic optic neuropathy
AAION is characterized by acute unilateral vision loss that may progress to bilateral vision loss if not diagnosed and treated with haste. It classically occurs in individuals older than 55 years. These individuals often present with a combination of other symptoms as well, such as new onset headache, scalp tenderness, pain at the temples or occipital area of the head, jaw claudication, unintentional weight loss, fever and malaise. The affected optic nerve head typically has an average cup-to-disc ratio and presents as edematous and pallid. There may be flame hemorrhages and cotton-wool spots in conjunction with the edema. There is a generalized reduction in the affected eye’s visual field.
Bilateral optic nerve head OCT shows the small cup-to-disc ratio, robust nerve fiber layer in both eyes and superior nerve fiber swelling in the left eye.
Fundus photo of the patient’s left optic nerve at follow-up visit 5 weeks after initial presentation. Sectoral edema of the optic nerve head has resolved, and the disc margin and retinal vasculature are clearly visible.
AAION is most common in individuals of Northern European descent. It is a consequence of inflammation of the posterior ciliary arteries and indicates a systemic vasculitis of the medium and large arteries. This vasculitis is most commonly known as either giant cell arteritis or temporal arteritis.
Due to the nature of the vasculitis, one or more of the following are typically elevated: erythrocyte sedimentation rate, C-reactive protein and platelets. The definitive diagnostic test for AAION is a temporal artery biopsy. Vision loss is typically permanent, and it is imperative that this condition is treated with corticosteroids quickly to prevent bilateral blindness.
Optic neuritis
ON typically presents with acute unilateral vision loss and an accompanying afferent pupillary defect. The mean age for initial presentation is 33 years. The majority of individuals report pain with eye movements in the affected eye. It is common to have reduced color vision and red color saturation in the impaired eye. The affected optic nerve head may appear with or without edema depending on the location of the inflammation. These individuals most often have a central or cecocentral visual field defect in the affected eye.
ON is most common in Caucasians. While ON is most commonly associated with multiple sclerosis (MS), it can stem from a variety of systemic autoimmune disorders and, thus, can present with varying systemic symptoms. In the case of demyelinating optic neuritis due to MS, the patient might report numbness or tingling in the extremities, fatigue and blurred vision when body temperature increases (Uhthoff’s sign). Vision loss typically improves, but recurrences over time are common.
This patient’s management
In this case, our patient presented with a NAION in her left eye. Her unilateral vision reduction and inferior altitudinal visual field defect support this diagnosis. As previously noted, she had the classic sectoral edema of her optic nerve head indicative of NAION. While our patient did not discover her vision loss upon waking, sudden discovery of vision loss is the second most common way these patients become aware of field loss.
We counseled our patient that while there is no treatment for her vision loss and that it is most likely permanent, it is important to manage her vascular risk factors. It is uncommon for the previously affected eye to suffer from another ischemic event, but it is common for the unaffected eye to later develop a NAION if systemic risk factors are not addressed.
While our patient had a strong family history of vascular disease and presented with an elevated blood pressure in our office, her blood pressure was within normal limits when she presented to her internist. Thus, she was not started on antihypertensive medications and instead she began a low dose aspirin.
We assert that our patient has white-coat hypertension (WCHT) or masked hypertension (MHT), as her blood pressure fluctuated in different settings at different times of day. In a study published by Mancia and colleagues, WCHT was defined as in-office blood pressure higher than 140/90 mm Hg, for which our patient would have qualified in our office.
MHT was defined as in-office blood pressure lower than 140/90 mm Hg but later elevated when measured at home, for which our patient could have potentially qualified with the blood pressure measured by her internist. This study found that although these individuals were not diagnosed with sustained hypertension at the initial visit, the likelihood of developing sustained hypertension over the following 10 years was significantly higher than in true normotensive individuals. The risk of developing sustained hypertension for WCHT was 2.51 times greater and for MHT was 1.78 times greater than for normotensives. As a consequence of this research, the clinician must take into account the statistically significant implications of WCHT and MHT and the effect it might have on the patient’s ocular and systemic health.
Our patient also had an elevated total cholesterol level of 240 mg/dL, but a protective HDL cholesterol level of 73 mg/dL. To determine if our patient would be an appropriate candidate for hyperlipidemia treatment, we utilized the Framingham Heart Study’s cardiovascular risk model to calculate her risk of heart attack within the next 10 years. Our patient did not have a score that qualified her for treatment with a cholesterol lowering drug, even if one were to utilize her highest systolic blood pressure in the calculation.
Most cardiovascular risk models do not take into account family history of cardiovascular disease, which in this patient’s case is extensive. At a follow-up visit, the patient reported that not only did all of her siblings have hypertension, but one also had a NAION, and another presumably had a central retinal artery occlusion. Although our patient presented with slightly atypical systemic risk factors for NAION, when all is considered together, she has several vascular red flags. It is imperative that she live a healthy lifestyle and see her internist as recommended to continue to monitor for vascular changes. Once the diagnosis of NAION has been made, it is judicious to try to determine the cause of the ischemia, due to the high prevalence of recurrence of NAION in the fellow eye.
- References:
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- National Heart, Lung, and Blood Institute. Risk assessment tool for estimating your 10-year risk of having a heart attack. http:// cvdrisk.nhlbi.nih.gov. Updated November 2014. Accessed June 9, 2015.
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- Tamhankar M, at al. Nonarteritic anterior ischemic optic neuropathy: epidemiology, pathogenesis, and etiologies. UpToDate: Wolters Kluwer Health. http://www.uptodate.com/contents/nonarteritic-anterior-schemic-optic-neuropathy-epidemiology-pathogenesis-and-etiologies. Updated June 6, 2013. Accessed June 9, 2015.
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- Wilson PWF, et al. Estimation of cardiovascular risk in an individual patient without known cardiovascular disease. UpToDate: Wolters Kluwer Health. http://www.uptodate.com/contents/estimation-of-cardiovascular-risk-in-an-individual-petient-without-known-cardiovascular-disease. Updated April 6, 2015. Accessed June 9, 2015.
- For more information:
- Brynn Peterson, OD, is a recent graduate of Pacific University College of Optometry in private practice in Wayzata, Minn. She can be reached at pete2654@pacificu.edu.
- Leonid Skorin Jr., OD, DO, MS, FAAO, FAOCO, is a Primary Care Optometry News Editorial Board member who practices in Albert Lea, Minn. He can be reached at the Mayo Clinic Health System; skorin.leonid@mayo.edu.
- Edited by Leo P. Semes, OD, FAAO, a professor of optometry, University of Alabama at Birmingham and a member of the Primary Care Optometry News Editorial Board. He may be reached at lsemes@uab.edu.
Disclosures: Peterson and Skorin report no relevant financial disclosures. Failed screening.