대한안과학회지 2018 년제 59 권제 4 호 J Korean Ophthalmol Soc 2018;59(4):347-354 ISSN 0378-6471 (Print) ISSN 2092-9374 (Online) https://doi.org/10.3341/jkos.2018.59.4.347 Original Article 특발망막앞막에서수술전정면빛간섭단층촬영영상과수술후시력호전과의관계 The Correlation between Preoperative En Face Optical Coherence Tomography and Postoperative Visual Prognoses in Idiopathic Epiretinal Membranes 안성현 1 이태은 1,2,3 유인천 1,2,3 안민 1,2,3 조남천 1,2,3 정진구 1,2,3 Sung Hyun Ahn, MD 1, Tae Eun Lee, MD, PhD 1,2,3, In Cheon You, MD, PhD 1,2,3, Min Ahn, MD, PhD 1,2,3, Nam Chun Cho, MD, PhD 1,2,3, Jin Gu Jeong, MD 1,2,3 전북대학교의학전문대학원안과학교실 1, 전북대학교임상의학연구소 2, 전북대학교병원의생명연구원 3 Department of Ophthalmology, Chonbuk National University Medical School 1, Jeonju, Korea Research Institute of Clinical Medicine, Chonbuk National University 2, Jeonju, Korea Biomedical Research Institute, Chonbuk National University Hospital 3, Jeonju, Korea Purpose: To investigate the correlation between en face optical coherence tomography and improvements in the postoperative prognoses of idiopathic epiretinal membranes. Methods: The medical records of 59 epiretinal membrane patients who had epiretinal membrane peeling between January 2005 and January 2016, and were followed up for > 12 months, were retrospectively reviewed. The preoperative en face images were divided into four sections involving three circular areas (6,000 µm diameter circle, 3,000 μm diameter circle, and 1,000 μm diameter circle) and one square (6,000 6,000 μm). The surface area where no epiretinal adhesion was present was quantified by measuring the number of black pixels using image-editing software (Adobe Photoshop CS6, Adobe Systems, San Jose, CA, USA). Then the correlations among the value of black pixels, preoperative and postoperative visual acuities, and central retinal thickness were analyzed. Results: The best-corrected visual acuity (BCVA) was significantly increased after epiretinal membrane peeling (p < 0.001), and the central retinal thickness was significantly decreased (p < 0.001). As the number of black pixels in the circles and the square in the en-face images increased, the postoperative BCVA significantly increased (r = 0.645, p < 0.001; r = 0.590, p < 0.001, respectively). Conclusions: As the nonadhesive surfaces of the epiretinal membrane and the retina in preoperative en face images became wider, the increments of the BCVA after surgery were greater. Therefore, en face optical coherence tomography can be used to predict prognosis after epiretinal membrane peeling. J Korean Ophthalmol Soc 2018;59(4):347-354 Keywords: En face image, Epiretinal membrane, Optical coherence tomography Received: 2017. 9. 21. Revised: 2018. 1. 17. Accepted: 2018. 3. 29. Address reprint requests to Jin Gu Jeong, MD Department of Ophthalmology, Chonbuk National University Hospital, #20 Geonji-ro, Deokjin-gu, Jeonju 54907, Korea Tel: 82-63-259-3473, Fax: 82-63-250-1960 E-mail: terathan@naver.com * The study was presented as an e-poster at the 117th Annual Meeting of the Korean Ophthalmological Society 2017. * Conflicts of Interest: The authors have no conflicts to disclose. 망막앞막은 Iwanoff에의해 1865년처음기술되었으며, 1 내경계막표면에여러종류의세포들이증식하면서섬유세포막을형성하여발생하는것으로알려졌다. 2 이러한섬유세포막의견인력은황반의구조적손상및황반부종을일으킬수있으며, 이로인해시력저하나변시증등의증상이나타난다. 3-5 1978년 Machemer가처음으로유리체절제술을통한망막앞막의제거를보고하였고, 현재시력저 c2018 The Korean Ophthalmological Society This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. 347
- 대한안과학회지 2018 년제 59 권제 4 호 - 하및변형시등의증상이동반된경우수술적제거가치료로선호되고있다. 6-8 빛간섭단층촬영 (optical coherence tomography, OCT) 은망막의두께및부피를정량적으로측정할수있기때문에망막앞막과같은중심오목질환의진단및경과평가에유용하다. 최근에는스펙트럼영역빛간섭단층촬영 (spectral domain OCT, SD-OCT) 의발달로더욱빠른속도로고해상도검사가가능하게되었고, 이로인해망막의미세구조와시력에대한연구가활발해졌다. 9-11 망막앞막수술의예후인자로서수술전시력, 증상이나타난기간, 유리체망막견인유무, 변시증정도, 망막앞막의두께, 수술전황반부종유무등이제시되고있다. 12-15 또한망막앞막의 OCT를통한분석이망막앞막수술의예후를예측하는데도움이된다고알려져있다. 12,16-18 Kim et al 15 및 Kim et al 19 은후향적및전향적관찰증례연구에서 SD-OCT를통한망막앞막의유착정도가수술전수술의난이도를평가하는데유용하며, 망막앞막제거의시작부위를결정하는데도움을준다고하였다. 또한 Seidel et al 18 및 Kim et al 19 은망막앞막이침윤된범위가넓을수록망막조직의손상이커서, 망막앞막과망막의유착정도를파악하는것이수술후예후를예측하는데도움이된다고하였다. 이에저자들은망막과유착이없는망막앞막의상승부위를파악하는것이수술후예후를예측하는데유용할것으로생각하였다. 따라서저자들은망막과유착이없는망막앞막의범위에대해 OCT En Face 영상을통해정량화를시도하였으며, 시력예후및망막중심두께의변화와의상관관계를알아보고자하였다. 대상과방법 2005년 1월부터 2016년 1월까지전북대학교병원안과를내원하여특발망막앞막으로진단된후망막앞막제거술을받은환자중 12개월이상경과관찰한환자 59명 59 안의의무기록을후향적으로분석하였다. 20/50 이하의시력감소가보이는경우, 20/50 이상의시력이라도변시증등의증상이심한경우에수술적처치를시행하였다. 수술은유리체절제술을시행하였고, 경도의백내장이있는경우에는백내장수술을동시에시행하였다. 특발망막앞막은망막앞막이후유리체박리이외에다른안과적질환없이황반에국한된경우로하였다. 포도막염, 외상, 망막혈관질환, 망막박리수술등에의한이차망막전막은대상군에서제외하였다. 당뇨망막병증, 나이관련황반변성, 녹내장등시력에영향을미칠수있는안과적질환이있 는환자도제외하였다. Lens Opacities Classification System (LOCS) Ⅲ 분류에서 NO3, C3, P3 이상의백내장을동반한경우는수술전빛간섭단층촬영신호강도에영향을미칠수있고, 또한이러한환자에서망막앞막제거술과백내장수술을같이시행한경우시력호전정도가커서연구결과에영향을미칠수있기때문에대상군에서제외하였다. 또한유리체절제술만시행하였으나경과관찰중백내장이발생한경우도대상군에서제외하였다. 환자군의나이, 성별, 술전및술후 12개월째최대교정시력을조사하였다. 술전 CIRRUS TM HD-OCT4000 (Carl Zeiss, Oberkochen, Germany) 을이용한빛간섭단층촬영을시행하였고, 이를통해술전및술후 12개월째중심망막두께 (central retinal thickness, CRT) 를조사하였다. 또한 macular cube 512 128 scan을 advanced visualization 모드를통해 internal limiting membrane (ILM) slab을기준으로 En Face OCT 영상을얻었다. OCT 내소프트웨어를통해얻어진이영상에서망막앞막의상승부위가 line scan ophthalmoscope (LSO) image 위에자동적으로오버레이되기때문에이부위는 black pixel로나타난다. 이렇게얻어진영상들을 early treatment diabetic retinopathy study (ETDRS) subfields에준하여, 3개의원 (6,000 μm diameter circle, 3,000 μm diameter circle, 1,000 μm diameter circle) 과 1개의사각형 (6,000 6,000 μm square), 총 4가지로영상의크기를편집하였다. 그리고각각의이미지를그래픽편집소프트웨어 (Adobe Photoshop CS6, Adobe Systems, San Jose, CA, USA) 에서불러온뒤, 창 메뉴의 막대그래프 항목에서 256색중검은색에해당하는레벨0 ( 레벨0 레벨255) 의픽셀값을 black pixel 값 으로정하였다. 따라서영상에서검은색이많을수록 black pixel 값이높게나타나며, 이부위를망막앞막의유착이없는부위라고생각할수있다 (Fig. 1-3). 이를바탕으로 black pixel 값, 수술전후최대교정시력및수술전후중심망막두께와의상관관계에대하여분석하였다. 모든환자에서전신마취또는 2.0% Lidocaine과 0.5% Bupivacaine을이용한구후마취후수술을진행하였다. 수술은두명의망막전문의에의해시행되었으며, 23게이지평면부유리체절제술을시행하였다. 필요에따라수정체유화술및인공수정체삽입술을함께시행하였다. 망막앞막은안내집게및흡입바늘을사용하여제거하였다. 필요에따라내경계막제거를함께시행하였으며, 1.0 mg/ml 의인도사이아닌그린염색약을사용하여, 30초간유입용액을정지시켜충분히염색시킨후내경계막및망막앞막 348
- 안성현 외 : 망막앞막과 정면빛간섭단층촬영 - A B C D Figure 1. Four types of En Face optical coherence tomography (OCT) images. 6,000 6,000 μm square (A), 6,000 μm diameter circle (B), 3,000 μm diameter circle (C), and 1,000 μm diameter circle (D). The original En Face OCT image (A) was edited in three circles according to the early treatment diabetic retinopathy study subfields. Then we obtained the black pixel values of each of the images. A B Figure 2. Large area of elevated epiretinal membrane (ERM) peeling. Line scanning ophthalmoscope image (A) and En Face image (B). Black pixelated areas calculated automatically reveal elevated ERM in (B). It shows that the retina and the ERM have a wide area of contact in (A). And the larger the area of contact, the lower the black pixel value may be considered as shown as the narrow area of black color in (B). A B Figure 3. Small area of elevated epiretinal membrane (ERM) peeling. Line scanning ophthalmoscope image (A), and En Face image (B). It shows that the retina and the ERM have a narrow are of contact in (A). And the narrower the area of contact, the greater the black pixel value may be considered as shown as the greater area of black color in (B). 349
- 대한안과학회지 2018 년제 59 권제 4 호 - 을제거하였다. 본연구는전북대학교병원생명의학연구윤리심의위원회 (institutional review board, IRB) 의승인을받았으며 ( 승인번호 : 2017-06-014), 헬싱키선언을준수하였다. 통계는 SPSS statics software package version 20.0 (IBM, Armonk, NY, USA) 을사용하였고, 단변량분석은 Wilcoxon signed rank test로검정하였고, black pixel 값, 수술전후최대교정시력및수술전후중심망막두께등의인자들간의분석은선형회귀모형을사용하였다. 또한 p값이 0.05 미만인경우를통계학적으로의의가있는것으로판단하였다. 결과 대상환자 59명 59안중남자는 27명, 여자는 32명이었으며, 수술시나이는 41세에서 80세로평균 64.8 ± 8.9세 였다. 59안중 23안은인공수정체안이었으며, 36안은수정체안이었다. 수정체안 36안중 15안은망막앞막제거술과백내장수술을동시에시행하였다. 술전평균최대교정시력은 0.51 ± 0.29 logmar였고, 수술후 12개월째평균최대교정시력은 0.24 ± 0.23 logmar로유의한시력변화가관찰되었다 (p<0.001) (Table 1). 수술전평균중심망막두께는 468.97 ± 101.44 μm, 수술후평균중심망막두께는 354.75 ± 63.20 μm로유의하게감소하였고 (p<0.001), 수술전후중심망막두께차이는평균 113.53 ± 86.11이었다 (Table 2). 또한수술전 En Face 영상의평균 black pixel 값은 6,000 6,000 μm square (6,000 squre), 6,000 μm diameter circle (6,000 circle), 3,000 μm diameter circle (3,000 circle), 1,000 μm diameter circle (1,000 circle) 에서각각 42,893.92 ± 6,826.66, 33,799.24 ± 5,652.37, 8,094.85 ± 1,958.61, 861.90 ± Table 1. Demographic characteristics and clinical features of the patients Characteristics Value Number of patients 59 Sex (male:female) 27:32 Age at surgery (years) 64.8 ± 8.9 Preoperative lens state (phakic:pseudophakic) 36:23 Types of operation (phacovitrectomy:vitrectomy) 15:44 BCVA (logmar) (preoperative:postoperative) 0.51 ± 0.29:0.24 ± 0.23 * BCVA change (logmar) 0.27 ± 0.24 Values are presented as mean ± SD unless otherwise indicated. SD = standard deviation; BCVA = best corrected visual acuity * p-value < 0.001, Wilcoxon signed rank test. Table 2. Central retinal thickness after and before epiretinal membrane peeling (ERMP), and values of the black pixelated area on En Face images Value CRT (μm) (preoperative:postoperative) 468.97 ± 101.44:354.75 ± 63.20 * CRT chage (μm) 113.53 ± 86.11 6,000 6,000 μm square (pixels) 42,893.92 ± 6,826.66 6,000 μm diameter circle (pixles) 33,799.24 ± 5,652.37 3,000 μm diameter circle (pixles) 8,094.85 ± 1,958.61 1,000 μm diameter circle (pixles) 861.90 ± 391.41 Values are presented as mean ± SD unless otherwise indicated. CRT = central retinal thickness; SD = standard deviation. * p-value < 0.001, Wilcoxon signed rank test. Table 3. Correlation between the visual prognosis and values of the black pixelated area on En Face images Postoperative BCVA BCVA change Preoperative BCVA r * p-value r * p-value r * p-value 6,000 6,000 μm square pixels 0.300 0.021-0.312 0.016 0.645 <0.001 6,000 μm diameter circle pixels 0.247 0.059-0.321 0.013 0.590 <0.001 3,000 μm diameter circle pixels 0.199 0.131-0.125 0.344 0.352 0.006 1,000 μm diameter circle pixels 0.162 0.220 0.035 0.792 0.163 0.218 BCVA = best corrected visual acuity. Spearman correlation test; Statistically significant. 350
- 안성현외 : 망막앞막과정면빛간섭단층촬영 - 391.41이었다 (Table 2). 시력호전정도와 6,000 square 및 6,000 circle의 En Face 영상 black pixel 값은각각높은상관관계를보였다 (r=0.645, p<0.001) (r=0.590, p<0.001) (Table 3, Fig. 4). 또한 3,000 circle의 black pixel 값도시력호전정도와유의한상관관계를보였으나 (r=0.352, p=0.006), 1,000 circle 의 black pixel 값과시력호전정도는통계학적으로유의 하지않았다 (p=0.218) (Table 3). 반면, En Face 영상 black pixels 값과수술전후중심망막두께변화량은통계적으로유의하지않았다 (Table 4). 시력과중심망막두께와의상관관계를분석한결과, 수술전중심망막두께및수술전후중심망막두께변화량은수술후시력과유의한상관관계를보였으나 (r=0.360, p=0.005) (r=0.286, p=0.028), 시력호전정도와는통계학적으로유 A B Figure 4. Scattergram showing the significant positive correlation between the change in best corrected visual acuity (BCVA) and preoperative epiretinal membrane area (pixels) with no retinal contact. (A) BCVA and 6,000 6,000 μm square (r = 0.645, p < 0.001), and (B) BCVA and 6,000 μm diameter circle (r = 0.590, p < 0.001). Table 4. Correlation between the values of the black pixelated area on En Face images and the values of central retinal thickness (CRT) change r * CRT change p-value 6,000 6,000 μm square pixels 0.055 0.680 6,000 μm diameter circle pixels 0.042 0.758 3,000 μm diameter circle pixels 0.081 0.540 1,000 μm diameter circle pixels 0.040 0.764 * Spearman correlation test. Table 5. Correlation between the visual prognosis and the values of the central retinal thickness (CRT) Postoperative BCVA BCVA change r * p-value r * p-value Preoperative CRT 0.360 0.005-0.026 0.843 CRT change 0.286 0.028 0.179 0.174 Preoperative BCVA 0.580 <0.001 0.663 <0.001 BCVA = best corrected visual acuity. Spearman correlation test; Statistically significant. Table 6. Correlation between the values of the central retinal thickness (CRT) Postoperative CRT CRT change r * p-value r * p-value Preoperative CRT 0.536 <0.001 0.786 <0.001 * Spearman correlation test; Statistically significant. 351
- 대한안과학회지 2018 년제 59 권제 4 호 - 의하지않았다 (Table 5). 또한수술전중심망막두께는수술후중심망막두께및수술전후중심망막두께변화량과높은상관관계를보였다 (r=0.536, p<0.001) (r=0.786, p<0.001) (Table 6). 수술전시력과수술후시력은유의한상관관계를가졌고 (r=0.580, p<0.001), 수술전시력과시력호전정도의상관관계도유의한결과를보였다 (r=0.663, p<0.001) (Table 5). 고찰 망막앞막제거술은난이도및위험도가높은수술인데, 이는안내집게를이용하여망막앞막을잡을때망막앞막아래에있는망막을잡으면서신경절세포층에비가역적인손상을초래할수있기때문이다. 따라서망막과의유착이없는망막앞막부위의범위가넓을수록집게를이용해서잡기가쉬우며, 안전하게망막앞막을제거하는것을용이하게해준다. Wilkins et al 20 은 OCT를통해망막앞막과망막표면사이의분리가없는전반적유착 (global adherence) 과망막표면과일부유착이있으나망막표면과명확한분리가관찰되는국소적유착 (focal adherence) 으로망막앞막을구분하였고, 전반적유착형태가국소적유착을보이는망막앞막보다수술이더어렵고합병증발병이높을것이라고주장하였다. 또한 Kim et al 19 은 SD-OCT 를이용하여망막앞막의유착형태를국소적유착 (focal), 전반적유착 (broad), 완전유착 (complete) 3가지로분류하여망막제거술의난이도와의상관관계를분석하였고, 완전유착의경우국소적유착보다수술의난이도가 8.6배증가한다고주장하였다. 따라서망막앞막과망막표면사이의유착이심할수록수술난이도가증가하여시력예후가좋지않을것으로생각해볼수있다. 또한 Seidel et al 18 및 Kim et al 19 은망막앞막의침윤 (infiltration) 정도, 제거술후남아있는내경계막, 그리고시력예후와의관계에대하여연구하였는데, 망막앞막그자체로도망막조직에손상을주기때문에, 망막앞막이침윤된범위가넓을수록망막조직이더많이손상을받는다고하였다. 본연구에서는 HD-OCT를이용하여망막앞막을분석하였는데, 망막앞막과망막의접촉이클수록 En Face 영상에서검은색으로나타나는부위의면적이작고 (Fig. 2), 접촉이작을수록검은색으로나타나는부위의면적이큰것을알수있었다 (Fig. 3). 따라서그래픽편집소프트웨어를이용하여이러한 En Face 영상의 black pixel 값을구하여망막과의접촉이없는부위를수치화하였다. 한편 Pavlidis et al 21 도 En Face OCT 영상의 black pixel 값을이용하여, 유리체절제술후망막앞막의예후인자로서 En Face OCT의유용성에대하여연구하였는데, Pavlidis et al 21 의연구에서는 6,000 square En Face OCT 영상의 black pixel 값만을분석한반면, 본연구에서는 ETDRS subfields에준하여 En Face OCT 영상을더세분화하였다는점에서차이가있다. 한편, 본연구에서는 3,000 circle의 black pixels 값보다 6,000 square 및 6,000 circle의 black pixel 값이시력호전정도와더높은상관관계를보였고, 저자들은추가적으로 6,000 square에서 3,000 circle을제외한영역의 black pixel 값 (6,000 square black pixel 값 3,000 circle black pixel 값 ) 과 6,000 circle의 black pixel 값에서 3,000 circle을제외한영역의 black pixel 값 (6,000 circle black pixel 값 3,000 circle black pixel 값 ) 을구하였고시력호전정도와의상관관계를분석하였는데, 각각 3,000 circle보다더높은상관관계를보였다 (r=0.631, p<0.001) (r=0.580, p<0.001). 망막앞막수술의경우막을얼마나제거해야하는지에대한지침이없으나, 대부분의술자들은망막혈관궁내에는견인이없어야한다고믿으며, 망막손상없이모든방향으로많이제거해야한다고생각한다. 그러므로본연구의결과는중심부분뿐만아니라, 중심이외부분의망막앞막유착도시력예후에중요하며, 따라서수술시가능한한넓은범위의망막앞막을제거해야한다는주장을뒷받침한다고생각하였다. 추후망막앞막의망막유착범위, 망막앞막제거범위및시력예후와의관계에대한추가적인연구가필요할것으로생각된다. 본연구에서는그래픽편집소프트웨어 (Adobe Photoshop CS6, Adobe Systems) 에서레벨 0에해당되는검은색만 black pixel로정의하여 black pixel 값 을구하였는데, En Face 이미지에서어둡게나타나는부분을다른어두운색의레벨로확장하여 pixel 값을구한다면결과에변화가있을수있기때문에이는본연구의한계점으로생각된다. 수술후시력에영향을주는예후인자로지금까지제시된것들은저자마다다양하다. 수술전중심망막두께중심망막두께와관련하여 Kim et al 15 와 Kwon et al 22 의연구에서술전망막중심두께가최종시력과상관관계를보였는데, 본연구에서도술전망막중심두께와 12개월째최대교정시력이유의한상관관계를보였다 (r=0.360, p=0.005). 또한 Suh et al 23 의연구에서는술전중심망막두께는술후중심망막두께, 술후시력, 시력호전정도와상관관계가있다고하였고, 시력호전정도를제외하고는 (p=0.843), 352
- 안성현외 : 망막앞막과정면빛간섭단층촬영 - 본연구에서도술전중심망막두께가술후중심망막두께 (r=0.536, p<0.005) 및술후시력과유의한상관관계를보였다 (r=0.360, p=0.005) (Table 5, 6). 수술전후중심망막두께변화반면, Suh et al 23 의연구에서중심망막두께변화정도는술후시력및시력호전정도와상관관계가없다고보고하였는데, 본연구에서는술후시력과는유의한상관관계를보였으나 (r=0.286, p=0.028), 시력호전정도와는통계학적으로유의하지않았다 (p=0.174) (Table 5). 따라서중심망막두께가시력예후에미치는영향에대해서는추후다양한연구가필요할것으로보인다. 또한본연구에서는 En Face 영상의 black pixel 값과수술전후중심망막두께변화량은통계학적으로유의하지않았는데, 망막앞막의침윤정도외에중심망막두께에영향을주는다른요인이있는지에대한연구가필요할것으로보인다. 수술전시력많은연구들에서수술전시력은수술후최종시력에영향을주는예후인자로서알려져있다. 15,22,24 본연구에서도수술전시력은수술후 12개월째시력과유의한상관관계를가졌고 (r=0.580, p<0.001), 시력호전정도와도높은상관관계를보였다 (r=0.663, p<0.001) (Table 5). 따라서수술전시력은망막앞막에서중요한예후인자로생각된다. 망막앞막에서유리체절제술후수정체핵경화의빠른진행이보고되었으며, 수술적치료에따른가장많은합병증으로알려져있다. 7,24-26 Ando et al 27 은망막앞막환자에서유리체절제술만시행한환자와백내장수술을동시에받은환자를비교하였는데, 2년경과관찰후유리체절제술만받은환자군의 65% 가백내장진행으로인해시력이저하되었다고보고하였다. 본연구에서는유리체절제술만시행한환자와, 백내장수술을동시에시행한환자를따로분류하지않았으며, 수술전중등도이상의백내장이있는경우는대상군에서제외하였다. 따라서백내장수술여부및수술전백내장정도에대한분석이없다는점은본연구의제한점으로생각한다. 이외에도후향적연구이며대상환자수가많지않았다는점, 상대적으로경과관찰기간이짧아재발에대한분석을시행하지못했다는제한점이있다. 따라서향후, 백내장에의한영향까지고려하여더많은환자를대상으로장기간의전향적연구가필요하다. 결론적으로, 유리체절제술을통한망막앞막제거술을시행하는경우망막과의유착이없는부위가넓을수록더욱좋은예후를기대할수있으며, 수술전정면빛간섭단 층촬영영상을통해이러한부위를파악하여수술을용이하게할수있다. 따라서망막앞막의수술후시력예후예측인자로서정면빛간섭단층촬영영상이유용할것으로생각된다. REFERENCES 1) Koutsandrea CN, Apostolopoulos MN, Alonistiotis DA, et al. Indocyanine green-assisted epiretinal membrane peeling evaluated by optical coherence tomography and multifocal electroretinography. Clin Ophthalmol 2007;1:535-44. 2) Smiddy WE, Maguire AM, Green WR, et al. Idiopathic epiretinal membranes. Ultrastructural characteristics and clinicopathologic correlation. Ophthalmology 1989;96:811-20. 3) Michels RG. Vitreous surgery for macular pucker. Am J Ophthalmol 1981;92:628-39. 4) de Bustros S, Rice TA, Michels RG, et al. Vitrectomy for macular pucker: use after treatment of retinal tears or retinal detachment. Arch Ophthalmol 1988;106:758-60. 5) Ando F, Ohba N, Touura K, Hirose H. Anatomical and visual outcomes after episcleral macular buckling compared with those after pars plana vitrectomy for retinal detachment caused by macular hole in highly myopic eyes. Retina 2007;27:37-44. 6) McDonald HR, Verre WP, Aaberg TM. Surgical management of idiopathic epiretinal membranes. Ophthalmology 1986;93:978-83. 7) de Bustros S, Thompson JT, Michels RG, et al. Nuclear sclerosis after vitrectomy for idiopathic epiretinal membranes. Am J Ophthalmol 1988;105:160-4. 8) Margherio RR, Cox MS Jr, Trese MT, et al. Removal of epimacular membranes. Ophthalmology 1985;92:1075-83. 9) van Velthoven ME, Faber DJ, Verbraak FD, et al. Recent developments in optical coherence tomography for imaging the retina. Prog Retin Eye Res 2007;26:57-77. 10) Ko TH, Fujimoto JG, Schuman JS, et al. Comparison of ultrahighand standard-resolution optical coherence tomography for imaging macular pathology. Ophthalmology 2005;112:1922.e1-15. 11) Schmidt-Erfurth U, Leitgeb RA, Michels S, et al. Three-dimensional ultrahigh-resolution optical coherence tomography of macular diseases. Invest Ophthalmol Vis Sci 2005;46:3393-402. 12) Odrobina D, Michalewska Z, Michalewski J, et al. Long-term evaluation of vitreomacular traction disorder in spectral-domain optical coherence tomography. Retina 2011;31:324-31. 13) Kinoshita T, Kovacs KD, Wagley S, Arroyo JG. Morphologic differences in epiretinal membranes on ocular coherence tomography as a predictive factor for surgical outcome. Retina 2011;31:1692-8. 14) Falkner-Radler CI, Glittenberg C, Hagen S, et al. Spectral-domain optical coherence tomography for monitoring epiretinal membrane surgery. Ophthalmology 2010;117:798-805. 15) Kim J, Rhee KM, Woo SJ, et al. Long-term temporal changes of macular thickness and visual outcome after vitrectomy for idiopathic epiretinal membrane. Am J Ophthalmol 2010;150:701-9.e1. 16) Shiono A, Kogo J, Klose G, et al. Photoreceptor outer segment length: a prognostic factor for idiopathic epiretinal membrane surgery. Ophthalmology 2013;120:788-94. 17) Theodossiadis PG, Theodossiadis GP, Charonis A, et al. The pho- 353
- 대한안과학회지 2018 년제 59 권제 4 호 - toreceptor layer as a prognostic factor for visual acuity in the secondary epiretinal membrane after retinal detachment surgery: imaging analysis by spectral-domain optical coherence tomography. Am J Ophthalmol 2011;151:973-80. 18) Seidel G, Weger M, Stadlmüller LG, et al. Association of preoperative optical coherence tomography markers with residual inner limiting membrane in epiretinal membrane peeling. PLoS One 2013;8:e66217. 19) Kim JS, Chhablani J, Chan CK, et al. Retinal adherence and fibrillary surface changes correlate with surgical difficulty of epiretinal membrane removal. Am J Ophthalmol 2012;153:692-7, 697.e1-2. 20) Wilkins JR, Puliafito CA, Hee MR, et al. Characterization of epiretinal membrane using optical coherence tomography. Ophthalmology 1996;103:2142-51. 21) Pavlidis M, Georgalas I, Körber N. Determination of a new parameter, elevated epiretinal membrane, by En Face OCT as a prognostic factor for pars plana vitrectomy and safer epiretinal membrane peeling. J Ophthalmol 2015;2015:838646. 22) Kwon SI, Ko SJ, Park IW. The clinical course of the idiopathic epiretinal membrane after surgery. Korean J Ophthalmol 2009;23: 249-52. 23) Suh MH, Seo JM, Park KH, Yu HG. Associations between macular findings by optical coherence tomography and visual outcomes after epiretinal membrane removal. Am J Ophthalmol 2009;147: 473-80.e3. 24) Rice TA, de Bustros S, Michels RG, et al. Prognostic factors in vitrectomy for epiretinal membranes fo the macula. Ophthalmology 1986;93:602-10. 25) Pournaras CJ, Donati G, Brazitikos PD, et al. Macular epiretinal membranes. Semin Ophthalmol 2000;15:100-7. 26) Donati G, Kapetanios AD, Pournaras CJ. Complications of surgery for epiretinal membranes. Graefes Arch Clin Exp Ophthalmol 1998;236:739-46. 27) Ando A, Nishimura T, Uyama M. Surgical outome on combined procedures of lens extraction, intraocular lens implantation, and vitrectomy during removal of the epiretinal membrane. Ophthalmic Surg Lasers 1998;29:974-9. = 국문초록 = 특발망막앞막에서수술전정면빛간섭단층촬영영상과수술후시력호전과의관계 목적 : 특발망막앞막환자에서수술전정면빛간섭단층촬영 (En Face optical coherence tomography) 영상과술후예후와의관련성에대하여알아보고자한다. 대상과방법 : 2005 년 1 월부터 2016 년 1 월까지특발망막앞막으로진단된후망막앞막제거술을받은환자중 12 개월이상경과관찰한환자 59 명 59 안의의무기록을후향적으로분석하였다. 술전 En Face 영상을 early treatment diabetic retinopathy study (ETDRS) subfields 에준하여, 3 개의원 (6,000 μm diameter circle, 3,000 μm diameter circle, 1,000 μm diameter circle) 과 1 개의사각형 (6,000 6,000 μm square), 총 4 가지로나누었고, 그래픽편집소프트웨어 (Adobe Photoshop CS6, Adobe Systems, San Jose, CA, USA) 를통해영상의 black pixel 값을측정하여, 망막앞막의유착이없는부위를수치화하였다. 이후 Black pixel 값, 수술전후시력및수술전후중심망막두께와의상관관계에대하여분석하였다. 결과 : 망막앞막제거술후최대교정시력은유의하게증가하였고 (p<0.001), 중심망막두께는유의하게감소하였다 (p<0.001). 6,000 6,000 μm square 및 6,000 μm diameter circle 의 En Face 영상 black pixel 값이증가할수록수술전후최대교정시력호전정도가증가하였으며, 이는통계학적으로유의하였다 (r=0.645, p<0.001) (r=0.590, p<0.001). 결론 : 망막앞막환자의수술전 En Face 영상에서망막앞막과망막의유착이없는부위의면적이클수록수술후최대교정시력의증가량이많았다. 따라서망막앞막의수술후시력예후예측인자로서정면빛간섭단층촬영영상이유용할것으로생각된다. < 대한안과학회지 2018;59(4):347-354> 354