대한안신경의학회지 : 제 3 권제 2 호 Clin Neuroophthalmol 3(2):91-96, December 2013 ISSN: REVIEW 시력소실 오선영 1,2 전북대학교의학전문대학원신경과학교실 1, 전북대학교병원신경과 2 Visual lo

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1 대한안신경의학회지 : 제 3 권제 2 호 ISSN: REVIEW 시력소실 오선영 1,2 전북대학교의학전문대학원신경과학교실 1, 전북대학교병원신경과 2 Visual loss Sun-Young Oh, MD 1,2 Department of Neurology, 1 Chonbuk National University School of Medicine, 2 Chonbuk National University Hospital, Jeonju, Korea The visual loss can be caused by variable diseases that involve the afferent visual pathway from retina diseases to the visual cortex lesion. Targeted detailed history taking and the subsequent neuro-ophthalmologic examination in addition to standard neurologic examination can lead to a correct diagnosis. In this article, clinical approaches to diagnose for visual loss are reviewed and some clinical syndromes are described. Keywords: Vision; History taking; Examination 서론눈으로들어오는사물이망막에맺히고시신경을통해대뇌시각중추까지들시각경로 (afferent visual pathway) 를통해들어오는과정은망막광수용체 시신경 (optic nerve) 시각교차 (optic chiasm) 시각로 (optic tract) 가쪽무릎핵 (lateral geniculate nucleus) 시각로부챗살 (optic radiation) 일차시각피질 (primary visual cortex) 의경로를따른다. 일시적인또는영구적인시력소실은응급실이나외래에서흔히만날수있으며안과적질환이나시신경병 (optic neuropathy) 또는뇌내시각경로를침범하는질환에서나타날수있다. 본장에서는시력소실에대한일련의병력청취와검사들, 그리고신경안과적계통검사를통한진단접근과시력소실을유발하는대표적인질환인시신경병증에대해간단히기술한다 병력청취시력소실이단안성인지양안성인지가병력청취에서가장중요 한질문은인데, 단안성시력소실은대개시신경교차이전의병변 (prechiasmal lesion) 즉, 안구자체질환또는시신경질환에서발생하며 (Tables 1, 2, Fig. 1), 양안성시력소실은대개시신경교차 (optic chiasm), 시신경로 (optic tract), 외측무릎체 (lateral geniculate), 시각부챗살 (optic radiation) 혹은후두엽 (occipital lobe) 병변, 즉시신경교차이후병터에서발생한다 (Table 3). 시력소실이단안성혹은양안성인지환자가잘구별하지못한다면, 환자에게각눈을가리게하면서검사하면단안성혹은양안성소실인지확인한다. 전형적으로, 동측반맹 (homonymous hemianopia) 이있는환자는측두 (temporal) 시야결손이있는쪽에만시야결손이있다고인지할수있다. 가장흔한일시적양안시력저하의원인은편두통시각전조, 후두엽일과성뇌허혈발작그리고후두엽간질 (Table 4) 이며 1,2 기타드문원인으로는소아에서의두부손상, 고혈압성뇌병증, 임신중독증, 그리고 cyclosporine 등여러약제독성에의한것으로대개이러한피질시각상실 (cortical blindness) 은수시간에서수일지속된다. Correspondence to: Sun-Young Oh, MD Department of Neurology, College of Medicine, Chonbuk National University, 20 Geonji-ro, Deokjin-gu, Jeonju , Korea Tel: ; FAX: ; ohsun@jbnu.ac.kr Received: Aug. 23, 2013 / Accepted: Sep. 15, 2013 Copyright 2013 The Korean Society of Neuro-Ophthalmology 91

2 Oh S-Y Visual loss 그다음질문은색각 (color vision) 에이상이있는지인데, 즉색이흐리게보이거나, 희미하게없어져보이거나색을구분하지못할수있으며, 빨간색을갈색이나오렌지색으로보인다고하면붉은색탈포화 (red desaturation) 를시사한다. 시신경병증은색각에영향을미치나, 굴절이상, 매체이상 ( 각막, 수정체, 유리체 ), 그리고일부망막질환들에서는색각은보존된다. 망막병증과시신경교차의후부의시력소실에서는일반적으로색각은보존된다. 만약시력소실이일시적이라면, 시력소실의양상을살피고, 커튼이내려오는것처럼보이거나, 스위스치즈처럼군데군데시력이손실되는지를물어야한다. 그렇다면시신경및망막에발생하는허혈성질환을시사한다. 또는시력소실이섬광이나번뜩이는색, 운동과관련되어있는지를물으며, 이러한양성시현상은편두통이나망막의질환과관련이있다. 단안혹은양안으로침범이되는지도확인하며, 음성현상을동반하는양안의침범은후방의병변 Table 1. 단안성시력소실의원인 1) 굴절이상 2) 매체이상 ( 각막이상, 수정체혼탁, 유리체혼탁등 ) 3) 망막 / 황반병변 (retinal and macular diseases) 4) 시신경병 (optic neuropathies) 5) 기능적인시력소실 6) 약시 을, 허혈성손상에서기원함을의미한다 (Fig. 2). 2,3 다음으로해야할질문은시력소실의시간적인진행양상 (tempo of visual loss) 인데, 일시적이라면얼마나오래지속되었는지이며, 수초간의시력소실은유두부종이나시신경유두의드루젠과연관이있다. 허혈성손상이라면약 5분정도지속되는경향이있고, 편두통은 20분에서수시간동안지속이된다. 시력소실이지속적이라면, 구체적인발생시간, 즉일과중혹은아침기상시에발생했는지 Table 2. 황반질환과시신경질환의감별 (clinical characteristics of macular and optic nerve lesions) Characteristics Macular Lesions Optic Nerve Lesions Reduced central acuity Yes Photostress test Long recovery Normal recovery Pain No Yes if inflammatory Yes RAPD No Yes Visual acuity Variable Variable Color vision Mildly reduced Often severe Amsler grid Metamorphopsia Scotoma Visual field Central scotoma or diffuse depression Variable Visual evoked responses ERG Normal or mildly abnormal Abnormal (full-field ERG often normal; multifocal ERG is usually abnormal) ERG, electroretinogram; RAPD, relative afferent papillary defect. Abnormal Normal Monocular visual loss - Ocular examination (refraction, media) - Pupils (RAPD?) - Fundsus 2. Cannot see through to the fundus 3. No RAPD 2. Can see through to the fundus 3. No RAPD 2. Can see through to the fundus 3. RAPD 4. Abnormal retina 2. Can see through to the fundus 3. RAPD 4. Normal, swollen or pale otic nerve Ocular media - cornea - anterior chamber: inflammation Hemorrhage - cataract - vitreous: Inflammation Hemorrhage Macular disease - macular hole - central serous retinopathy - macular hemorrhage - macular degeneration - retinal dystrophies Retina disease - retinal detachment - retinal vascular occlusion Optic nerve disease Fig. 1. 단안성시력소실의국소화 (The anatomical localization of monocular visual loss)

3 시력소실 오선영 등에대해묻는다. 허혈성시신경병증과시신경염은아침에일어날때발생하는경향이있으며, 중심망막동맥폐쇄 (central retinal artery occlusion, CRAO) 는흔히깨어있는동안에발생한다. 또한시력소실을알게된경위를구체적으로물어봐야한다. 환자가무심코한눈을가리고본눈에시력문제가있다고알게되었는지아니면갑자기양눈을뜨고있는동안에시력에뭔가이상을느꼈고각 Table 3. 일시적또는영구적인양안성시력소실의원인 2 - Vascular Vertebrobasilar ischemia (posterior cerebral artery territory) Cerebral anoxia Cerebral venous thrombosis (superior sagittal sinus) Hypertensive encephalopathy Malignant systemic hypertension Eclamsia - Head trauma - Occipital mass (e.g., tumor, abscess, or hemorrhage) - Demyelinating disease - Infection Occipital abscess Meningitis Progressive multifocal leukoencephalopathy Creutzfeldt-Jacob disease - Central nervous system toxicity Cyclosporine Taclolimus (FK-506) Mercury - Metabolic Hypoglycemia Porphyria Hepatic encephalopathy - Migraine - Occipital lobe seizures - Degenerative Alzheimer disease Posterior cortical atrophy 눈을확인한후에한쪽눈이침범되었다고인지하였는지를묻는다. 때때로환자는시력소실이갑자기발생했다고생각하지만, 자세하게병력청취를해보면시력소실이무심코한눈으로보았을때갑자기발견되었다고하고, 오른쪽어깨를살펴볼때코로왼쪽눈을가리면서보는때와같이, 왼쪽눈을가리지않음에도불구하고환자가오른쪽눈으로만보았을때와같은경우에발견할수있다. 마지막으로, 연관된증상들을확인해야하며, 예로, 오른쪽눈에일과성흑암시 (amaurosis fugax) 및일시적인왼쪽편마비가있는환자에서심한우측의경동맥협착이있거나, 시신경염이있는환자에서눈을움직일때안구통증이흔히동반된다. 또는동반증상들이기저전신질환의진단을내리는데도움이될수있는데, 즉, 턱관절의파행이나두피압통등은거대세포동맥염 (giant cell arteritis) 을, 또는급성파종뇌척수염 (acute disseminated encephalomyelitis) 에서선행되는바이러스감염등이다. 환자는연관된증상이주증상과관련있다고생각하지않기때문에그증상들을확인하는것이중요하다. 2. 시신경염 (optic neuritis) 시력소실을초래하는흔한질환중의하나로시신경병의가장흔한원인이되는시신경염에대해간단히기술한다. 탈수초화를동반하는시신경의염증으로인한시신경병을시신경염 ( optic neuritis ) 이라하며, 이러한염증성시신경염을일으키는원인은다양하다 (Table 5). 원인질환으로매독이나고양이발톱병 (cat scratch disease) 등감염성질환부터유육종증 (sarcoidosis), 시신경척수염 (neuromyelitis optica, NMO) 등비감염성질환등도포함된다. 본고에서는전형적인염증성시신경병증, 즉시신경염 (optic neuritis) 의임상적인특징과진단검사, 치료를포함하여비전형적시신경염으로시신경척수염 (NMO) 과기타시신경염을유발하는질환들에대해살펴보고자한다. 1,3 Table 4. Characteristics of the Three Most Common Causes of Binocular Transient Visual Loss 2 Visual symptoms Migrainous Visual Aura Occipital Transient Ischemic Attack Occipital Seizures Negative (hemianopia or blindness) Positive Very rich, moving Often black and white, scintillating, shimmering, jagged edges Positive Simple visual phenomena (phosphenes, bubbles) Colored Progression of symptoms Typical migrainous march, with progression Sudden onset and disappearance Usually not progressive of symptoms over time Duration of visual symptoms Typically 20 to 30 minutes A few minutes Usually brief (seconds) Often repeated Headache Associated symptoms Migrainous headache typically follows the aura May be absent Headache follows Visual aura may be followed by other migrainous aura (mostly sensory) Brow headache possible at the time of visual symptoms Vertebrobasilar ischemia: -Vertigo, dizziness -Imbalance -Diplopia -Bilateral extremity weakness None Often none May be associated with other seizures 93

4 Oh S-Y Visual loss Transient monocular visual loss Urgent ophthalmologic evaluation Funduscopy showing: Normal fundus Retinal arterial emboll Branch retinal artery occlusion Cotton wool spots Venous stasis retinal Disk edema (anterior ischemic optic neuropathy) Ocular transient ischemic event Retinal (central retinal artery or its branches) Optic nerve (posterior ciliary arteries) Choroid (posterior ciliary arteries) Eye (ophthaimic artery) Abnormal ocular examination: Intraocular hypertension (inermittent angle closure glaucoma) Hyphema Dry eyes Keratoconus Proptosis Retinal detachment Central retinal vein occlusion Optic nerve swelling Anomalous optic nerve (drusen, crowded) Ocular or orbital disease Emergently Look for vascular risk factors Look for symptoms / signs of giant cell arteritis Neurological examination (contralateral symptoms/signs) Cardiovascular examination (carotids/heart) Sedimentation rate (ESR), C-reactive protein (CRP), CBC, platelets Carotid workup: Carotid duplex scanning and transcranial Doppler MRA or CT-angiogram Electrocardiogram Age> 50 years Systemic symptoms of giant cell arteritis Elevated ESR and CRP Normal carotid arteries Giant cell arteritis Look for other causes: Trans-esophageal echocardiogram Look for arrhythmia Look for hypercoagulable states Antiphospholipid antibodies Look for autoimmune diseases Ipsilateral carotid artery stenosis or occlusion: Atheroma Dissection Fibromuscular dysplasia Radiation arteriopathy Arteritis (Takayasu...) Cardiac source of emboli Aortic arch atheroma Hypercoagulable state Autoimmune disease (Lupus, Sjögren,...) Antiphospholipid antibodies Central retinal artery spasm Ophthaimic artery stenosis Fig. 2. Diagnostic approach for monocular visual loss

5 시력소실 오선영 Table 5. Classification of inflammatory optic neuropathy 2 1. Optic neuritis associated with demyelinating disease - Idiopathic optic neuritis - Optic neuritis as a manifestation of - Multiple sclerosis - NMO - ADEM 2. Optic neuritis associated with infectious diseases - Bacterial infections: syphilis, cat scratch diseases - Viral infections: herpes zoster, herpes simplex, HIV, EBV - Parasitic infections: toxoplasmosis, systicercosis - Fungal infections: cryptococcosis, aspergillosis 3. Postvaccination optic neuritis - Hepatitis B virus, rabies virus, tetanus toxoid 4. Optic neuritis associated with other inflammatory disorders - Sarcoidosis - Systemic lupus erythematosus - Sjogren syndrome - Polyarteritis nodosa - Wegener granulomatosis - Inflammatory bowel disease - Behcet - Bee and wasp stings 5. Isolated recurrent optic neuritis (autoimmune optic neuritis) 1) 전형적인탈수초성시신경염 (Idiopathic demyelinating optic neuritis) 전형적인시신경염의경우 20대에서 50대사이의여자에호발하며, 급성단안의시력감소를주증상으로한다. 시력저하뿐아니라시야의감소, 색각의감소, 대비감도의감소등의시기능저하를보일수있으며그중환자가느끼는가장흔한증상은안통과함께시력의갑작스런감소이다 (Table 6). 전형적인탈수초성시신경염환자에서의시력감소는 2, 3일간에걸쳐일어나는것이대부분이고조금길면 7일에서 10일에걸쳐발생한다. 시력감소의정도는정상시력부터무광각까지다양하며성인의경우보통단안성인경우가많지만증상이없는반대쪽눈에도검사상시기능장애를보이기도한다. 섬광증상이시력저하가발생하기전에나타날수있고시신경염이치료된후에도지속되기도하는데, 시신경염에서의섬광증상은수평안구운동시잘나타나는특징을가지고있다. 시신경염에서특징적인증상은안통인데안통은크게안운동과상관없는안구주위의통증과안운동에의해악화되는안통으로나눌수있는데, 시신경염에만나타나는특이한증상은아니지만다른시신경병증과의감별에유용한증상이다. 섬광증상과마찬가지로시력저하가나타나기전에먼저안통이나타나기도한다. 색각이상이다양하게나타날수있는데이는시력저하보다더심한것이보통이다. 또불의밝기가정상눈에비해어둡게보이 Table 6. Common examination findings in optic neuritis Decreased vision Visual field defects Reduced color vision Uhthoff s symptom Decreased depth perception Pain Phosphenes; movement-induced, sound-induced Table 7. Common examination findings in optic neuritis Visual acuity loss Dyschromatopsia Reduced contrast sensitivity Reduced stereoacuity Visual field loss Afferent pupillary defect Normal or swollen optic nerve 고대비감도의장애도나타난다. 시신경염에서나타나는전형적인시야장애는중심암점이다. 하지만실제로중심암점을보이기보다는다양한다른형태의시야장애가나타나는경우가더많다 (Table 7). 2) 비전형적시신경염비전형적시신경염이란일차적인탈수초성염증반응에의한것이아니라이차적으로감염이나자가면역질환, 결체조직질환등의전신질환과관련되어발생한경우이다. 시신경염을동반하는자가면역질환들로는시신경척수염 (NMO), 전신성홍반성루푸스 (SLE), Antiphosphoid syndrome, 유육종 (Sarcoidosis), 쇼그렌증후군, 베쳇병 (Behcet s disease), 전신경화증등이알려져있다. 감염성질환은주로신경망막염 (Neuroretinitis) 의형태로나타나며 Bartonella henselae, 결핵 (Tuberculosis) 의원인균인 Mycobacterium tuberculosis, 브루셀라병 (brucellosis) 의원인이되는 brucellae, 라임병 (lyme disease) 을일으키는 Borrelia burgdorferi, 매독 (syphilis) 을일으키는 Treponema pallidum, 록키산열병의원인균이었던 rickettsia rickettsii 등이시신경염을일으킬수있고, Adenovirus, Coxachie virus, Cytomegalovirus (CMV), Epstein Barr virus (EBV), Human immune deficiency virus (HIV), Measles, Mumps, Rubeola, Rubella, Varicella and Herpes Zoster, Hepatitis A, B, C 등의바이러스도시신경을직접침범하거나간접적으로면역반응을촉진하여시신경염증을일으킬수있다. 비전형적인시신경염의증상을보일때는세밀한신경학적진찰과추가적인검사들을시행할수있는데뇌, 안와와척추자기공명영상촬영을필수적으로시행하는것이좋고그밖에척수검사, 혈청검사를시행하여 antinuclear antibldy test (ANA), Fluorescent treponemal antibody absorbtion (FTA-ABS), angiotensin-converting enzyme (ACE) level, Lyme titer, Chest X-ray 등 95

6 Oh S-Y Visual loss Table 8. 성인에서비전형적시신경염의특징 50세이상또는 12세이하동시혹은연속적인양측성시신경염발병후 2주가지나서까지악화되는심한시력저하 ( 빛감지불가능할정도 ) 2주이상지속되는안구통증안저소견전반부혹은후반부의뚜렷한부분적염증뚜렷한포도막염과망막정맥주위염시신경유두의심한팽대심한시신경유두출혈망막삼출황반별 ( 별황반삼출물, macular star) 3-5주후시력호전이전혀없거나계속악화됨다발성경화증의발생위험이낮음다발성경화증이외에다른전신질환의소견스테로이드치료가끝난뒤시력이악화됨가족력암의과거력시신경염이나다발성경화증병력없이시신경위축이있음 을시행하고, 망막의병변과시신경의병변을구별하기위해안과적인 검사로 Optical coherence tomography (OCT), Electroretinogram (ERG) 등을시행할수있겠다 (Table 8). 3. 시신경척수염 (NMO) 시신경척수염은과거 Devic disease 라고도알려진, 자가항체에의 해 ( 아 ) 급성의단안또는양안의시신경염과횡단성척수염을동반하 는중추신경계의탈수초질환의하나다. 횡단성척수염은시력소실을 선행해서또는뒤따라발생할수있다. 전형적인다발성경화증과임 상증상이비슷하고감별이어려웠지만, 최근중추신경계의수분통로 인 aquaporin-4 (AQP-4) 에대한자가항체가발견되면서 NMO 의발병 기전과임상특징에대한이해가증가되었다. 또한과거에는정상뇌영 상을진단기준으로여겨져왔으나최근 AQP-4 항체와연관한뇌영상 소견이알려지면서새로운진단기준이제시되고 (Table 9) NMO 진단 기준을모두만족하지않더라도척수염이나시신경염의일부증상, 또 는다른자가면역질환에서 AQP-4 항체를보이기도하여이를 NMO spectrum disorder 로따로분류하기도한다. 다발성경화증과비슷한 증상을보이지만일반적으로더심한시력소실을보이며, 시신경염은 Table 9. Revised diagnostic criteria for NMO (Wingerchuk et al. 2006) Two absolute criteria: i) optic neuritis ii) myelitis At least two of three supportive criteria: i) Presence of a contiguous spinal cord MRI lesion extending over three or more vertebral segments ii) MRI criteria not satisfying the revised McDonald diagnostic criteria for MS iii) NMO-IgG in serum 양안에동시에발병하거나 1 개월이내에연속적으로시신경염이발 생하는경우다발성경화증보다는 NMO 의가능성이더높겠다. 다발 성경화증에비해망막섬유두께의감소가심하며이는더광범위한 축삭손상을시사하며좋지않은예후를설명해준다. 예후는일반적 으로다발성경화증보다좋지못한것으로알려졌으며, 영구또는심 한시력소실과사지마비등을동반할수있다. 치료는주로급성기에 고용량의스테로이드정맥주사를하지만시력소실이심하고사지마 비를보이는경우에혈장혈장교환시행하는것이추천되고있다. 재 발방지를위해장기적으로면역억제치료를해야하며이를위해경구 스테로이드나 azathioprine 을투여할수있다. 그외이차약제로서 Rituximab, Cyclophosphamide 정주나 Mitoxantrone 정주, 또는 Mycophenolate mofetil 의경구투여를고려할수있다. 면역글로불린 (IVIG) 이효과적이라는보고도있다. 다발성경화증에서예방치료로 사용되는인터페론이 NMO 환자에서는연간재발률의감소를보이 지못했고, 일부환자에서는오히려증상의악화또는광범위한뇌병 변을일으키기도하였다고보고하고있어, NMO 에서인터페론의예 방치료는추천되지않고있다. REFERENCES 1. 김지수, 황정민외. 문답으로풀어가는신경안과진료. Seoul: E-public, Valerie Biousse, Nancy J Newman. Neuro-ophthalmology Illustrated. Thieme. New York: Stuttgart, 대한안신경학회. 안신경학. 서울 : 신흥메드사이언스,

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A 617 Special Issue Diabetic Retinopathy Won Ki Lee, M.D. Department of Ophthalmology The Catholic University of Korea College of Medicine Kangnam St. Mary s Hospital E mail : wklee@catholic.ac.kr Abstract R