Photo Essay: Unusual Optic Nerve Findings
Case 1:
Impending Central Retinal Vein Occlusion
An 82-year-old woman presented with a 4-day history of “filmy vision” in the right eye. Her history included mitral valve prolapse with regurgitation, for which she took warfarin and digoxin, and mild hyperlipidemia, which was controlled with diet. The results of recent carotid artery studies were negative.
The patient’s visual acuity was 20/30 in the right eye. A dilated funduscopic evaluation revealed mild retinal vein dilation and tortuosity. Numerous dot and blot hemorrhages were scattered throughout the fundus (A). A fluorescein angiogram revealed an impending nonischemic central retinal vein occlusion (CRVO).
The patient returned 20 days later, complaining that her vision had deteriorated further. Her visual acuity was only 20/60 in the right eye. A dilated funduscopic examination revealed optic disc congestion; increased retinal vein tortuosity and dilation; and a significantly increased number of dot, blot, and flame-shaped hemorrhages. The hemorrhages now involved the macula, which explained the patient’s worsening visual acuity. A cottonwool spot (infarction of the nerve fiber layer) was visible just temporal to the optic disc (B).
Predisposing factors for CRVO include systemic arterial hypertension, ECG abnormalities (such as those seen in patients with mitral valve prolapse and regurgitation), diabetes mellitus, peptic ulcer, and thyroid disease.1 In this case, the mitral valve prolapse and regurgitation were thought to be the underlying cause. This type of occlusion is believed to arise from either thrombus formation or emboli at the level of the lamina cribrosa.
The patient was referred back to her primary care physician for reevaluation of her systemic therapy, and she is being monitored monthly for evidence of ischemic changes in the iris or retina.
The treatment options for patients with CRVO are limited. Scatter panretinal photocoagulation is indicated for iris or retinal neovascularization. Chronic macular edema, such as seen in this patient, carries the risk of significant visual morbidity. Up to 60% of patients with this condition have a visual acuity of less than 20/125 after 3 years.2 Focal macular laser photocoagulation is not effective for this type of macular edema.2,3
Case 2 on next page
REFERENCES:
1. Hayreh SS, Zimmerman B, McCarthy MJ, et al. Systemic diseases associated with various types of retinal vein occlusion. Am J Ophthalmol. 2001;131:61-77.
2. Central Vein Occlusion Study Group. Evaluation of grid pattern photocoagulation for macular edema in central vein occlusion. The central vein occlusion study group M report. Ophthalmology. 1995;102:1425-1433.
3. Gaudric A, Giorgi F, Sterkers M, et al. Photocoagulation with the argon laser in cystoid macular edema in retinal venous occlusions. Apropos of 68 cases [in French]. J Fr Ophtalmol. 1988;11:319-326.
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Case 2:
Resolving Central Retinal Vein Occlusion
Inability to focus and blurred vision in the right eye of recent onset prompted a 71-year-old woman to seek medical attention. Her vision had deteriorated progressively over 2 weeks; now her visual acuity measured 20/100 in the right eye and 20/25 in the left eye. There was no afferent pupillary defect, and the intraocular pressure was normal in both eyes.
The patient was taking hydrochlorothiazide, 5 mg/d, for longstanding hypertension and aspirinmeprobamate, 200 mg/d, for arthritis and headaches. Her blood pressure was 128/70 mm Hg, and auscultation revealed no carotid bruits. The patient’s complete blood cell count; erythrocyte sedimentation rate; and C-reactive protein, blood glucose, and lipid levels were all normal. A carotid duplex ultrasonogram showed no hemodynamically significant stenosis and essentially normal velocities of blood flow.
A slit-lamp examination revealed mild nuclear sclerotic cataracts in both eyes. A dilated funduscopic examination disclosed a moderately congested optic nerve with dilated and tortuous retinal vessels (A). Scattered throughout the fundus were dot, blot, and flame-shaped hemorrhages. A few yellowish white cottonwool spots were also seen. A fluorescein angiogram confirmed a nonischemic central retinal vein occlusion (CRVO).
The patient returned 5 weeks later. The vision in the right eye had improved to 20/40. A dilated funduscopic examination found resolving optic disc congestion, less dilation and tortuosity of the retinal blood vessels, and resolving retinal hemorrhages and cotton-wool spots (B).
Spontaneous improvement can occur in CRVO, especially if the condition remains nonischemic (ie, if neovascularization of the iris or retina does not occur). All patients with ischemic CRVO and those at high risk for conversion to ischemic status (ie, who show capillary nonperfusion on fluorescein angiographic examination) should be followed up monthly for 6 months. Up to 30% of eyes with nonischemic CRVO will become ischemic in 3 years.1
If fluorescein angiography is not available, a relative afferent pupillary defect test may provide additional diagnostic and prognostic information and help determine the risk of ischemia and neovascularization.2 If an afferent pupillary defect develops, ischemia of the retina will likely ensue.
Case 3 on next page
REFERENCES:
1. Greenberg PB, Gupta G. Current management of retinal vein occlusion. Retinal Physiol. 2005;2:18-23.
2. Hayreh SS, Klugman MR, Beri M, et al. Differentiation of ischemic from non-ischemic central retinal vein occlusion during the early acute phase. Graefes Arch Clin Exp Ophthalmol. 1990;228:201-217.
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Case 3:
Optic Disc Hypoplasia
A 62-year-old man was referred for consultation by his optometrist because of a suspicious-looking optic nerve head in the left eye. The patient felt that his vision was good, and he had no history of unusual eye findings. This was his first dilated eye examination.
The patient’s corrected visual acuity was 20/20 in both eyes. His intraocular pressure and external eye findings were normal. Funduscopic examination revealed a normal optic disc and retina in the right eye (A). The left eye had a smaller optic disc than the right (B). A peripapillary halo, known as the double-ring sign, can also be seen. The outer ring represents the junction between the sclera and lamina cribrosa where the choroid is discontinuous; the inner ring represents the termination of the retinal pigment epithelium.1 Because this is a stationary condition, the patient’s prognosis is excellent.
Optic disc hypoplasia is a developmental anomaly that can affect visual acuity and visual fields in patients with a more severe optic nerve defect. Children who have optic disc hypoplasia require a thorough neurologic evaluation, because this finding is often associated with neuroendocrinologic abnormalities and CNS anomalies, such as chiasmal malformations (de Morsier syndrome).2
Case 4 on next page
REFERENCES:
1. Mosier MA, Lieberman MF, Green WR, Knox DL. Hypoplasia of the optic nerve. Arch Ophthalmol. 1978; 96:1437-1442.
2. Skarf B, Hoyt CS. Optic nerve hypoplasia in children: association with anomalies of the endocrine and CNS. Arch Ophthalmol. 1984;102:62-67.
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Case 4
Cholesterol Plaque
A 71-year-old man presented with a 6-week history of decreased vision in his right eye. The patient, who had hypertension and migraine headaches, had successfully recovered from a stroke that occurred 1 year earlier. His medications included aspirin, 81 mg/d, clopidogrel, atenolol, and furosemide. He also took gabapentin, 300 mg hs, for his migraine headaches. He had a remote history of cigarette smoking.
The patient’s corrected visual acuity was 20/40 in the right eye and 20/20 in the left. He was pseudophakic. The rest of his eye examination was unremarkable, except for a cholesterol plaque at the first bifurcation of the inferior retinal blood vessel at the optic disc margin. Sheathing of the vessels could be seen beyond the bifurcation.
A cholesterol (Hollenhorst) plaque is an endogenous retinal embolus. These emboli usually arise from an ulcerated atheromatous plaque in the carotid artery. Cholesterol plaques appear as single or multiple yellow or copper-colored refractile bodies. As was the case in this patient, they do not always obstruct blood flow.
Cholesterol plaques can cause some focal ischemia and, in rare instances, segmental retinal ischemia. Vision is not usually affected, except perhaps transiently, or if a macular branch artery is involved. Often, the plaque breaks apart over time, and the smaller segments move further “downstream” in the vasculature.
No carotid bruits were audible in this patient, and he was referred back to his primary care physician for further systemic evaluation.
Case 5 on next page
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Case 5:
Tilted-Disc Syndrome
A 32-year-old woman complained of increased blurring of her distance vision. Results of a refraction showed that she had worsening myopia in both eyes. An increase in her prescription corrected her visual acuity to 20/20 in both eyes.
The rest of her ocular examination was unremarkable except for the appearance of the optic nerve heads (A and B). The patient had tilted discs, which result from the oblique insertion of the optic nerve into the globe. The discs are often small and oval or D-shaped, with the axis directed obliquely. Sometimes, as in this patient, the axis is horizontal. In about 80% of patients, the condition is bilateral.1 Nasal sweeping of the retinal vessels (situs inversus), inferonasal fundus hypopigmentation from thinning of the retinal pigment epithelium and choroid, and a rim of exposed sclera known as a crescent can often be seen inferiorly (A). Most patients with this condition are myopic or have oblique astigmatism. Visual field defects that mimic superior bitemporal hemianopsias may occur as a result of the inferonasal fundus changes. Because tilted-disc syndrome is a stationary condition, the prognosis is good.
REFERENCE:
1. Walsh TJ. Visual field defects. In: Walsh TJ, ed. Neuro-Ophthalmology: Clinical Signs and Symptoms. 3rd ed. Philadelphia: Lea & Febiger; 1992:562-615.