ACUTE BILATERAL PERIPHERAL CONE SYSTEM DYSFUNCTION Takuji Kurimoto, MD, PHD,* Mineo Kondo, MD, PHD,† Masashi Nishimura, MD, PHD,* Shinichirou Oono, MD,* Yuichi Tagami, MD,* Norio Okamoto, MD,* Osamu Mimura, MD, PHD*
Purpose: To report electrophysiological and psychophysical findings in an unusual case with acute loss of the peripheral visual field bilaterally. Methods: A 19-year-old woman underwent fundus photography, fluorescein angiography, visual field testing, determination of full-field electroretinograms (ERGs) and multifocal ERGs (mfERGs), and rod-cone perimetry in addition to routine ophthalmologic examinations. Results: Findings of fundus examination and fluorescein angiography were completely normal, and best-corrected visual acuity was 1.0 in both eyes. However, static perimetry revealed a temporal field defect in the right eye and an arcuate scotoma in the left eye. Full-field ERG cone responses were significantly reduced, but rod responses were normal in both eyes. Psychophysical rod-cone perimetry demonstrated that the peripheral cone system was impaired whereas the rod sensitivity was completely normal. mfERGs showed that the local cone responses were well preserved in the central retina but were severely reduced in the peripheral retina in both eyes. Conclusions: These results indicate that there is an unusual retinopathy showing acute dysfunction of the peripheral cone system bilaterally whereas the rod system is functioning normally. RETINAL CASES & BRIEF REPORTS 2:193–195, 2008
From the *Department of Ophthalmology, Hyogo College of Medicine, Nishinomiya; and †Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
peripheral visual field bilaterally. Electrophysiologic and psychophysical examinations revealed that the peripheral cone system was nearly selectively affected whereas the rod system was relatively well preserved.
T
here are several retinal disorders that are characterized by an acute onset retinal dysfunction without visible fundus abnormalities. One of the representative diseases is acute zonal occult outer retinopathy (AZOOR),1–3 which is characterized by an acute loss of visual function in one or more zones of the visual field, photopsia, minimal ophthalmoscopic changes, and electroretinographic (ERG) abnormalities. Because the fundus is essentially normal at the early stages, the ERG findings are the key to make a differential diagnosis of these disorders. We report an unusual case with an acute loss of the
Case Report A 19-year-old woman visited our hospital with a complaint of a sudden decrease in her peripheral vision associated with photopsia in the right eye. At the initial examination, her best-corrected visual acuity was 1.0 in both eyes, but Humphrey static perimetry revealed a temporal field defect in the right eye and an arcuate scotoma in the left eye. Fundus examination and fluorescein angiography were normal in both eyes (Figure 1). Laboratory tests showed an elevated titer of antibodies for antinuclear, anti-SS-A and anti-SS-B, and salivary gland scintigraphy revealed a dysfunction of salivary gland. She was diagnosed with Sjo¨gren syndrome as a systemic complication. Autoimmune optic neuritis was initially suspected because a faint high-intensity area was detected in her optic nerve in the magnetic resonance images (MRI), and steroid pulse therapy was performed twice. However, her visual field defect gradually increased in both eyes, and the scotoma became denser (Figure 2, upper trace).
Reprint requests: Takuji Kurimoto, MD, PhD, Department of Ophthalmology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan; e-mail: [email protected]
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Fig. 1. Fundus photographs (upper trace) and fluorescein angiograms (lower trace) in our patient.
We next suspected a retinal disease and recorded the full-field ERGs from both eyes. The single-flash cone responses and 30-Hz flicker responses of the full-field ERGs were severely reduced in both eyes, but the rod responses were well preserved (Figure 3, upper trace). These findings indicated that the function of the cone system was extensively disturbed. To assess the topographic changes of cone function objectively, we also recorded the multifocal ERGs (mfERGs) from both eyes. The mfERGs showed that the local cone responses were well preserved in the central retina but were severely reduced in the peripheral retina in both eyes (Figure 3, lower trace). Subjective sensitivity profiles of the rod and cone visual systems were also tested by light-adapted and dark-adapted perimetry using a modified Humphrey Field analyzer.4 We found that the cone sensitivities were within normal range in the central retina, but were not measurable in the periphery in both eyes (Figure 2, lower trace). The rod sensitivity was near the borderline at all locations tested (Figure 2, lower trace). Based on these electrophysiologic and psychophysical tests, our patient was diagnosed with an acute, bilateral retinal dysfunction of the peripheral cone system. Western blot analysis was performed using bovine retinal proteins to determine whether there were any antiretinal antibodies in the sera of our patients, but could not detect any autoantibodies. We have followed this patient for 15 months, and her peripheral visual field defects did not recover, and her visual acuity remained 1.0 in both eyes.
Discussion Our patient presented with a retinal dysfunction with unusual characteristics. She had an acute onset, progressive visual field defect in the peripheral field bilaterally. We initially suspected optic neuritis be-
cause her fundus and angiograms were normal. However, we found that her visual field defects were mainly caused by retinal dysfunction because the fullfield and multifocal ERGs were clearly abnormal. Most unusual was that our electrophysiologic and psychophysical tests demonstrated that the peripheral cone system was predominantly affected whereas the rod system was well preserved entirely. We have reported three cases with bilateral peripheral cone dysfunction, where the peripheral cone system was selectively impaired, but the rod system was normal.5 The electrophysiologic and psychophysical findings in these three patients were very similar to our present patient; however, the time course of the changes was very slow, as with inherited retinal dystrophy. However, our patient is clearly different from the previous three cases because the onset and progression of our patient was very rapid. A search of Medline did not extract any studies reporting a patient who had a bilateral retinal dysfunction of the peripheral cone system with an acute course. Our patient showed several clinical findings that resembled those found in patients with AZOOR.1–3 AZOOR was first described by Gass as being characterized by female predominance, acute onset visual field defect without visible fundus abnormalities, abnormal ERGs, and association with autoimmune disease. Thus, our patient may be part of the wide spectrum of clinical entities with AZOOR. However, the
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Fig. 2. Upper: Results of Humphrey static perimetry. Humphrey static visual field showing reduced sensitivity in the peripheral area in both eyes. Lower: The cone and rod sensitivity profile. The cone sensitivity profiles were determined under a white background with 31 red (600 nm) spots across the 60-degree horizontal meridian of the posterior pole. For rod sensitivity, two thresholds for blue-green (500 nm) and red (650 nm) stimuli were determined after 45 minutes of dark adaptation. The cone sensitivities were within normal range in the central retina but were unmeasurable in the periphery in both eyes. In contrast, the rod sensitivity was near the borderline even in the peripheral field where the cone system was severely impaired.
Fig. 3. Upper: Full-field electroretinograms (ERGs). Single flash cone response and 30-Hz flicker responses are severely reduced in both eyes but rod responses were within normal range in both eyes. Lower: Multifocal ERGs recorded with the VERIS system using 61 hexagonal stimuli. Topographic map of the multifocal ERG shows that the local responses were well preserved in the central retina, but were severely reduced in the peripheral retina in both eyes.
References 1.
selective depression of the peripheral cone system in both eyes is unusual in patients with AZOOR. The exact etiology of our patient is not definite. Association of autoimmune disease (Sjo¨gren syndrome) and selective dysfunction of cone system in our patient suggested that the autoimmune system may be involved in the cause of this disorder. Thus, we examined the serum of our patient. However, autoantibodies to the retinal protein were not detected. In summary, we reported a case with acute, bilateral loss of peripheral cone function. Our patient may be part of the wide spectrum of AZOOR. The exact diagnosis of our patient requires further study.
2.
3.
4.
5.
Gass JDM. Acute zonal occult outer retinopathy. Donders lecture: The Netherlands Ophthalmological Society, Maastricht, Holland, June 19, 1992. J Clin Neuro-ophthalmol 1993; 13:79–97. Jacobson SG, Morales DS, Sun XK, et al. Pattern of retinal dysfunction in acute zonal occult outer retinopathy. Ophthalmology 1995;102:1187–1198. Gass JDM, Agarwal A, Scott IU. Acute zonal occult outer retinopathy: a long-term follow-up study. Am J Ophthalmol 2002;134:329–339. Jacobson SG, Voigt WJ, Parel JM, et al. Automated light- and dark adapted perimetry for evaluating retinitis pigmentosa. Ophthalmology 1986;93:1604–1611. Kondo M, Miyake Y, Kondo N, et al. Peripheral cone dystrophy: A variant of cone dystrophy with predominant dysfunction in the peripheral cone system. Ophthalmology 2004;111: 732–739.
Purpose: To report electrophysiological and psychophysical findings in an unusual case with acute loss of the peripheral visual field bilaterally. Methods: A 19-year-old woman underwent fundus photography, fluorescein angiography, visual field testing, determination of full-field electroretinograms (ERGs) and multifocal ERGs (mfERGs), and rod-cone perimetry in addition to routine ophthalmologic examinations. Results: Findings of fundus examination and fluorescein angiography were completely normal, and best-corrected visual acuity was 1.0 in both eyes. However, static perimetry revealed a temporal field defect in the right eye and an arcuate scotoma in the left eye. Full-field ERG cone responses were significantly reduced, but rod responses were normal in both eyes. Psychophysical rod-cone perimetry demonstrated that the peripheral cone system was impaired whereas the rod sensitivity was completely normal. mfERGs showed that the local cone responses were well preserved in the central retina but were severely reduced in the peripheral retina in both eyes. Conclusions: These results indicate that there is an unusual retinopathy showing acute dysfunction of the peripheral cone system bilaterally whereas the rod system is functioning normally. RETINAL CASES & BRIEF REPORTS 2:193–195, 2008
From the *Department of Ophthalmology, Hyogo College of Medicine, Nishinomiya; and †Department of Ophthalmology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
peripheral visual field bilaterally. Electrophysiologic and psychophysical examinations revealed that the peripheral cone system was nearly selectively affected whereas the rod system was relatively well preserved.
T
here are several retinal disorders that are characterized by an acute onset retinal dysfunction without visible fundus abnormalities. One of the representative diseases is acute zonal occult outer retinopathy (AZOOR),1–3 which is characterized by an acute loss of visual function in one or more zones of the visual field, photopsia, minimal ophthalmoscopic changes, and electroretinographic (ERG) abnormalities. Because the fundus is essentially normal at the early stages, the ERG findings are the key to make a differential diagnosis of these disorders. We report an unusual case with an acute loss of the
Case Report A 19-year-old woman visited our hospital with a complaint of a sudden decrease in her peripheral vision associated with photopsia in the right eye. At the initial examination, her best-corrected visual acuity was 1.0 in both eyes, but Humphrey static perimetry revealed a temporal field defect in the right eye and an arcuate scotoma in the left eye. Fundus examination and fluorescein angiography were normal in both eyes (Figure 1). Laboratory tests showed an elevated titer of antibodies for antinuclear, anti-SS-A and anti-SS-B, and salivary gland scintigraphy revealed a dysfunction of salivary gland. She was diagnosed with Sjo¨gren syndrome as a systemic complication. Autoimmune optic neuritis was initially suspected because a faint high-intensity area was detected in her optic nerve in the magnetic resonance images (MRI), and steroid pulse therapy was performed twice. However, her visual field defect gradually increased in both eyes, and the scotoma became denser (Figure 2, upper trace).
Reprint requests: Takuji Kurimoto, MD, PhD, Department of Ophthalmology, Hyogo College of Medicine, 1-1 Mukogawa-cho, Nishinomiya, Hyogo 663-8501, Japan; e-mail: [email protected]
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2008
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NUMBER 3
Fig. 1. Fundus photographs (upper trace) and fluorescein angiograms (lower trace) in our patient.
We next suspected a retinal disease and recorded the full-field ERGs from both eyes. The single-flash cone responses and 30-Hz flicker responses of the full-field ERGs were severely reduced in both eyes, but the rod responses were well preserved (Figure 3, upper trace). These findings indicated that the function of the cone system was extensively disturbed. To assess the topographic changes of cone function objectively, we also recorded the multifocal ERGs (mfERGs) from both eyes. The mfERGs showed that the local cone responses were well preserved in the central retina but were severely reduced in the peripheral retina in both eyes (Figure 3, lower trace). Subjective sensitivity profiles of the rod and cone visual systems were also tested by light-adapted and dark-adapted perimetry using a modified Humphrey Field analyzer.4 We found that the cone sensitivities were within normal range in the central retina, but were not measurable in the periphery in both eyes (Figure 2, lower trace). The rod sensitivity was near the borderline at all locations tested (Figure 2, lower trace). Based on these electrophysiologic and psychophysical tests, our patient was diagnosed with an acute, bilateral retinal dysfunction of the peripheral cone system. Western blot analysis was performed using bovine retinal proteins to determine whether there were any antiretinal antibodies in the sera of our patients, but could not detect any autoantibodies. We have followed this patient for 15 months, and her peripheral visual field defects did not recover, and her visual acuity remained 1.0 in both eyes.
Discussion Our patient presented with a retinal dysfunction with unusual characteristics. She had an acute onset, progressive visual field defect in the peripheral field bilaterally. We initially suspected optic neuritis be-
cause her fundus and angiograms were normal. However, we found that her visual field defects were mainly caused by retinal dysfunction because the fullfield and multifocal ERGs were clearly abnormal. Most unusual was that our electrophysiologic and psychophysical tests demonstrated that the peripheral cone system was predominantly affected whereas the rod system was well preserved entirely. We have reported three cases with bilateral peripheral cone dysfunction, where the peripheral cone system was selectively impaired, but the rod system was normal.5 The electrophysiologic and psychophysical findings in these three patients were very similar to our present patient; however, the time course of the changes was very slow, as with inherited retinal dystrophy. However, our patient is clearly different from the previous three cases because the onset and progression of our patient was very rapid. A search of Medline did not extract any studies reporting a patient who had a bilateral retinal dysfunction of the peripheral cone system with an acute course. Our patient showed several clinical findings that resembled those found in patients with AZOOR.1–3 AZOOR was first described by Gass as being characterized by female predominance, acute onset visual field defect without visible fundus abnormalities, abnormal ERGs, and association with autoimmune disease. Thus, our patient may be part of the wide spectrum of clinical entities with AZOOR. However, the
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Fig. 2. Upper: Results of Humphrey static perimetry. Humphrey static visual field showing reduced sensitivity in the peripheral area in both eyes. Lower: The cone and rod sensitivity profile. The cone sensitivity profiles were determined under a white background with 31 red (600 nm) spots across the 60-degree horizontal meridian of the posterior pole. For rod sensitivity, two thresholds for blue-green (500 nm) and red (650 nm) stimuli were determined after 45 minutes of dark adaptation. The cone sensitivities were within normal range in the central retina but were unmeasurable in the periphery in both eyes. In contrast, the rod sensitivity was near the borderline even in the peripheral field where the cone system was severely impaired.
Fig. 3. Upper: Full-field electroretinograms (ERGs). Single flash cone response and 30-Hz flicker responses are severely reduced in both eyes but rod responses were within normal range in both eyes. Lower: Multifocal ERGs recorded with the VERIS system using 61 hexagonal stimuli. Topographic map of the multifocal ERG shows that the local responses were well preserved in the central retina, but were severely reduced in the peripheral retina in both eyes.
References 1.
selective depression of the peripheral cone system in both eyes is unusual in patients with AZOOR. The exact etiology of our patient is not definite. Association of autoimmune disease (Sjo¨gren syndrome) and selective dysfunction of cone system in our patient suggested that the autoimmune system may be involved in the cause of this disorder. Thus, we examined the serum of our patient. However, autoantibodies to the retinal protein were not detected. In summary, we reported a case with acute, bilateral loss of peripheral cone function. Our patient may be part of the wide spectrum of AZOOR. The exact diagnosis of our patient requires further study.
2.
3.
4.
5.
Gass JDM. Acute zonal occult outer retinopathy. Donders lecture: The Netherlands Ophthalmological Society, Maastricht, Holland, June 19, 1992. J Clin Neuro-ophthalmol 1993; 13:79–97. Jacobson SG, Morales DS, Sun XK, et al. Pattern of retinal dysfunction in acute zonal occult outer retinopathy. Ophthalmology 1995;102:1187–1198. Gass JDM, Agarwal A, Scott IU. Acute zonal occult outer retinopathy: a long-term follow-up study. Am J Ophthalmol 2002;134:329–339. Jacobson SG, Voigt WJ, Parel JM, et al. Automated light- and dark adapted perimetry for evaluating retinitis pigmentosa. Ophthalmology 1986;93:1604–1611. Kondo M, Miyake Y, Kondo N, et al. Peripheral cone dystrophy: A variant of cone dystrophy with predominant dysfunction in the peripheral cone system. Ophthalmology 2004;111: 732–739.
