대한안과학회지 2008 년제 49 권제 11 호 J Korean Ophthalmol Soc 2008;49(11):1737-1745 DOI : 10.3341/jkos.2008.49.11.1737 군날개수술전후의각막형태검사기와파면수차계를이용한난시벡터분석및고위수차의변화 권상민 이동준 정우진 박우찬 동아대학교의과대학안과학교실 목적 : 군날개환자에서각막형태검사기와파면수차계를이용하여군날개크기에따른수술전후의난시벡터분석및고위수차의변화를알아보고자하였다. 대상과방법 : 환자 31 명 (34 안 ) 을대상으로군날개크기 3 mm 이상군과 3 mm 미만군으로나누어술전과술후 1 주, 1 개월, 3 개월에각막형태검사기와파면수차계를시행하여난시벡터분석, 고위수차의변화를알아보았다. 결과 : 술전 B (blurring strength) 값과고위수차값 (RMS) 은두군모두에서술후 3 개월째의미있는감소를보였으며 (P<0.05), 난시벡터의산포도에서는술후 3 개월째 3 mm 미만군은술후 (0,0) 점을향해모이지만, 3 mm 이상군은산발적으로분포하였다. 술전에대한술후 1 주째고위수차값의변화율을비교하면군날개크기 3 mm 미만군에서 3 mm 이상군에비하여의미있게변화율이컸다 (p<0.05). 결론 : 군날개환자에서군날개크기 3 mm 이상에비하여 3 mm 미만에서술후난시벡터의유의한개선및고위수차변화율이더크게나타났기때문에보다효과적인난시와고위수차의개선을위해선 3 mm 미만에서수술을고려하는것이바람직할것으로사료된다. < 대한안과학회지 2008;49(11):1737-1745> 군날개란섬유혈관조직이각막윤부를넘어각막으로침범하는질환을가리키며원인과기전은명확히알려져있지않지만각막윤부각결막상피장벽의진행성파괴로인한만성염증, 세포증식, 혈관형성등으로특징지어질수있다. 1 군날개를가진환자는난시의변화가오게되며군날개에의해비대칭적인직난시 (withthe-rule astigmatism) 가발생할수있음이보고되고있다. 2-4 군날개가난시를유발시키는정확한원인은잘알려져있지않지만군날개에의해각막이눌려지거나변형이생겨난시가유발될수있으며, 5-7 군날개가장자리의눈물막이각막난시를유발한다는가설도있다. 8 그러나기존의많은논문에서군날개수술후이러한난시의변화를해결할수있음을보고하였다. 9-12 < 접수일 : 2008 년 2 월 13 일, 심사통과일 : 2008 년 7 월 8 일 > 통신저자 : 박우찬부산시서구동대신동 3 가 1 동아대학교병원안과 Tel: 051-240-5227, Fax: 051-254-1987 E-mail: wcpark@dau.ac.kr * 본논문의요지는 2007 년대한안과학회제 98 회추계학술대회에서구연으로발표되었음. 최근수술후시력의질을평가하는하나의수단으로안구수차 (ocular aberration) 의개념이도입되었는데안구수차는평면파 (plane wavefront) 가 Snell s law 에따라굴절될때기대되는상과실제로존재하는상과의차이를나타내는것으로안구의형태가변하게되면수차또한변화하는것으로알려져있으며, 13,14 군날개또한각막전면의굴곡을변화시키기때문에불규칙적인난시의변화뿐아니라수술전후에안구수차 (ocular aberration) 가변할것으로예상되며군날개수술전후이러한안구수차를연구한논문을보면 Pesudovs and Figueiredo 15 가 67 안의군날개수술전후의고위수차의변화를관찰하였으며술전총고위수차값 (RMS) 0.94±0.83 micron 에서술후 0.45±0.35 micron 으로의미있게감소함을보고하였다 (P<). 그러나연구에서군날개수술전후고위수차의변화를알아보기위해각막형태검사기 (corneal topographer) 를사용하였으며파면수차계 (wavefront aberro meter) 를이용하여분석한연구는없었다. 그래서본저자들은이러한안구수차의변화를알아내기위해서는보다정확한고위수차분석의필요성을인식하여, 군날개환자에서파면수차계를이용하여군날개크기에따른수술전후의고위수차의변화를알아보았으며, 또한 1737
권상민외 : 군날개수술전후고위수차의변화 각막형태검사기를이용하여난시와난시축의변화를알아보기위해난시벡터분석 (power vector analysis) 을시행하였다. 대상과방법 2006 년 2 월부터 2007 년 6 월까지 3 개월이상경과관찰이가능했던군날개환자 31 명 34 안을대상으로하였으며, 원추각막이나각막궤양또는각막혼탁등의 Figure 1. Pterygium was measured at the slit lamp with the eye in the primary position. The measurements were taken from the limbus to the leading edge of pterygium and recorded in millimeter. 전안부질환을가지고있거나과거안구외상이나안과적수술을받았던환자는대상에서제외하였다. 군날개의크기는세극등으로검사하여각막윤부에서군날개두부의정점까지길이로정하며 3 mm 미만 18 안과 3 mm 이상 16 안으로나누었으며 (Fig. 1), 군날개크기를 3 mm 로나눈것은 Oner et al 16 이군날개환자 148 안 (108 명 ) 의연구에서군날개의크기 (maximal length) 3 mm 이상 (mean 2.22±1.14D) 에서 3 mm 미만 (mean 1.10±0.53D) 보다의미있게난시가증가되므로 (P<0.05) 이전에수술을고려해야함을보고하였으며저자들도군날개의크기가난시및난시축에미치는영항을알아보고자군날개크기 3 mm 기준으로경도 (<3 mm) 와중등도 ( 3 mm) 인두군으로나누어각각의술후난시벡터변화및고위수차값을비교분석하였다. 평균연령은 46.5 세였으며, 남녀비는 4:6 이었다. 수술방법은 Alcaine R (Alcon inc., US) 으로점안마취후, 2% lidocaine 을군날개주위의테논낭하에주입하고군날개조직과결막하섬유혈관조직을절제하며공막의출혈부위는전기소작하였다. -70 에서냉동보관된양막을 BSS (balanced salt solution) 와항생제로충분히세척하고양막을노출된공막의크기보다크게디자인하여상피가위로향하도록덮어준후주변부양막을결막밑에위치시키고, 10-0 nylon 을이용하여공막과단속봉합하며, 내직근위에서는양막과결막만을연속봉합하였다. M J J B 0 45 = = = = S + ( C ( C M 2 C / 2 / 2) cos( / 2) sin( 2α ) + J 2 0 + 2α ) J 2 45 (A) (B) Figure 2. (A) The 3 Cartesian coordinates (x, y, z) of each power vector correspond to the powers of 3 lenses that, in combination, fulfill a refractive prescription: a spherical lens of power M, a Jackson crossed cylinder of power J 0 with axes at 90 degrees and 180 degrees, and a Jackson crossed cylinder of power J 45 with axes at 45 degrees and 135 degrees. The Pythagorean length of the power vector, B, is a measure of overall blurring strength of a spherocylindrical lens or refractive error. (B) Power vector analysis (S=spherical diopters, C=cylindrical diopters, α=axis (degree), Power vector=(m, J 0, J 45)). 1738
대 한 안 과 학 회 지 2008년 제 49 권 제 11 호 치료용 렌즈를 올리고 압박붕대를 시행하여 수술을 마무리 하였고 수술은 모두 같은 술자에 의해 시행 되었 다. 수술 후, 각막 및 양막의 상피가 재생될 때까지 압박 붕대를 시행하였으며 상피가 재생된 후에는 Tarivid (Santen, Japan) 항생제와 1% Methyl-prednisolone 점안액을 하루 네번 2주간 사용 후 tapering하였으며, Mitomycin C는 사용하지 않았다. 환자는 수술 후 1, 3, 7, 14일째, 그 이후는 1개월 간격으로 6개월간 재발 과 기타 술 후 합병증에 대하여 경과 관찰 하였다. 술 전과 술 후 1주, 1개월, 3개월에 현성굴절검사 및 각막형태검사기(Corneal topograper, Oculus inc., Germany)와 파면수차계(LADARWAVE, Hart mann shack aberrometer, Alcon inc., US)를 시행하여 난시벡터분석, 코마수차, 구면수차, 전체수차의 변화를 알아 보았으며, 각막형태검사기 측정시 optical zone의 크기를 3 mm로 하여 산동없이 1회 시행하였 으며, 파면수차계의 측정은 Mydrine -P (Santen, Japan)를 5분 간격으로 3회 점안하여 환자를 충분히 산동시킨 후 암실에서 총 5회 실시하여 의미있는 3회 값을 이용하였고, optical zone의 크기는 6.5 mm와 4.0 mm 둘다 측정 하였다. Figure 2와 같은 수식으로 난시벡터분석을 시행하 여 M과 B값을 구하였으며, 여기서 M은 sperical equivalent이며, B값은 구면원주렌즈 또는 굴절오차 값의 blurring strength로 그 의미는 굴절오차에 대 17 한 벡터크기를 말한다. 통계적인 분석은 SPSS 15.0 for Window를 이용하여 wilcoxon signed rank test 및 analysis of variance (ANOVA)를 통해 각 군의 측정값을 비교하였으며, P<0.05를 유의한 차 이가 있다고 보았다. 결 과 각막형태검사기를 이용한 난시벡터분석과 현성굴절 검사 결과 군날개 크기 3 mm 미만 군에서 술 전 평균 B (blurring strength)값과 M (spherical equi valent)값은 0.93±0.45, 0.331±0.638이였던 것이 술 후 3개월째엔 0.59±0.43 (B)와 4±0.515 (M)로 의미 있게 감소 되었으며(P<0.05), 3 mm이상 군에서도 술 전 평균값이 1.97±0.64 (B)와 1.094± 1.494 (M)에서 술 후 3개월째 1.23±0.52 (B)와 0.526±1.029 (M)로 의미 있게 감소되었다(P<0.05). Figure 3. Pre- and post-operative topography pictures in a patient with pterygium. Astigmatism was with-the-rule preoperatively (A) but against-the-rule at the postoperative first week and postoperative third month (B)(C)(D). 1739
권상민외 : 군날개수술전후고위수차의변화 Table 1. Summary of the mean value and standard deviation of power vector analysis before and after pterygium surgery. M (spherical diopter + cylindrical diopter/2) and B (blurring strength) significantly decreased in <3 mm and 3 mm Mean±SD M J 0 J 45 B p-value for M and B* Pterygium size < 3 mm Pre op 0.331±0.638 0.228±0.691-0.045±0.436 0.931±0.446-1 Week later 0.282±0.449 0.225±0.646-0.035±0.393 0.811±0.432 and (Pre op vs 1 Wk) 1 Month later 0.107±0.623 0.159±0.566-0.031±0.266 0.733±0.476 and (Pre op vs 1 Mo) 3 Months later 4±0.515 0.091±0.512-3±0.191 0.594±0.428 and (Pre op vs 3 Mo) Pterygium size 3 mm Pre op 1 Week later 1 Month later 3 Months later 1.094±1.494 0.712±1.174 0.553±1.494 0.526±1.029 0.109±0.740-0.274±0.546-0.178±0.740-0.144±0.401-0±0.780 0.295±0.554 0.247±0.780 0.210±0.440 1.971±0.642 1.497±0.486 1.411±0.612 1.230±0.523 * Wilcoxon signed rank test for M and B; SD=standard deviation. - and (Pre op vs 1 Wk) and (Pre op vs 1 Mo) and (Pre op vs 3 Mo) Figure 4. Pre- and post-operative best corrected visual acuity (BCVA) profile in patients. There was no significant change between pre- and postoperative BCVA in both <3 mm and 3 mm. 그러나 3 mm 이상군에서는술전에있었던직난시가술후도난시로역전되는양상을볼수있었으며 (Fig. 3)(Table 1), 현성굴절검사결과술전에비해술후 3 개월째두군모두에서의미있는시력의변화는없었다 (Fig. 4). 난시벡터 (J 0, J 45 ) 의산포도에서군날개크기 3 mm 미만군은술전산발적으로분포되어있던양상이술후 (0,0) 점을향해모이고있는반면, 군날개크기 3 mm 이상군에서는술후에도산발적으로분포하게되며 (Fig. 5), 난시축의변화를살펴보면 3 mm 이상에서술전직난시가술후도난시로변화되며넓게분포하는반면, 3 mm 미만군에서는직난시가술후점차줄어들어 (0,0) 점을향함을알수있었다 (Fig. 6). 파면수차계시행 (pupil size=6.5 mm) 후고위수 차값 (RMS) 의변화는군날개크기 3 mm 미만군에서코마수차는술전 0.81±0.48 micron, 술후 3 달째 0.32±0.17 micron 이며, 구면수차는술전 0.36± 0.12 micron, 술후 3 달째 0.16±0.15 micron, 그리고전체수차에서술전 2.21±1.05 micron, 술후 3 달째 1.18±0.54 micron 으로술전과비교하여모두술후의미있는값의감소를보였으며 (p<0.05), 군날개크기 3 mm 이상군에서는코마수차에서술전 1.24± 0.61 micron, 술후 3 달째 0.53±0.26 micron, 구면수차에서술전 0.49±0.44 micron, 술후 3 달째 0.23±0.19 micron 이며, 전체수차에서술전 3.53± 1.54 micron, 술후 3 달째 1.81±0.74 micron 으로 3 mm 미만군과마찬가지로모두의미있는감소를보였다 (P<0.05)(Table 2). 고위수차값의변화율을그래프로나타내어두군을 1740
대한안과학회지 2008 년제 49 권제 11 호 Figure 5. Scattergraph shows the astigmatic component of the power vector as represented by the 2-dimensional vector (J 0, J 45), which is the projection of the power vector into the astigmatism plane formed by the coordinate axes (J 0, J 45). Preoperative manifest astigmatism is reduced, and the cluster of points gathered around the zero point at postoperative third month for pterygium size <3 mm (A) but, the cluster of points did not gather for pterygium size 3 mm at postoperative third month (B). Figure 6. Scattergraph of power vector (J 0, J 45) on average shows that astigmatic axes did not change for pterygium size < 3 mm at the postoperative 3 months (A). But preoperative astigmatic axes changed from with-the-rule to against-the-rule at the postoperative first week for pterygium size 3 mm (B). 비교하면코마수차와구면수차및전체수차모두에서술전에대한술후 1 주째변화율이군날개크기 3 mm 미만군에서 3 mm 이상군에비하여의미있게변화율이컸다 (Fig. 7). 1741
권상민외 : 군날개수술전후고위수차의변화 Table 2. Summary of mean value and standard deviation of high order aberrations with wavefront aberrometer before and after pterygium surgery (wavefront aberrometer pupil size=6.5 mm) Mean±SD (RMS, µm) Pre op 1 Wk 1 Mo 3 Mo Preop vs 1 Wk Pterygium size < 3 mm (6.5 mm*) p-value Preop vs 1 Mo Preop vs 3 Mo Coma aberration 0.81 ±0.57 0.47 ±0.44 0.36 ±0.28 0.32 ±0.29 Spherical aberration 0.56 ±0.27 0.41 ±0.18 0.34 ±0.12 0.25 ±0.13 Total aberration 2.21 ±1.72 1.84 ±1.17 1.51 ±1.39 1.18 ±1.21 Pterygium size 3 mm (6.5 mm*) Coma aberration 1.30±1.44 0.87±0.74 0.70±0.78 0.56±0.41 0.03 Spherical aberration 0.79±0.51 0.58±0.43 0.40±0.23 0.34±0.34 Total aberration 3.73±1.88 2.62±2.01 2.27±1.92 1.92±1.73 * Pupil size in wavefront aberrometer; Wilcoxon signed rank test for each aberration; Zernike total high order aberration; SD=standard deviation. Figure 7. Change rates of high order aberrations (coma A, spherical B, total C) were significantly greater in group I than in group II at the preoperative period vs postoperative first week period (pterygium size <3 mm= group I, pterygium size 3 mm= group II), (* p<0.05, Wilcoxon signed rank test). 고 찰 많은연구에서군날개는불규칙적인난시를유발하며군날개절제후이러한난시가감소됨을보고하였으나대부분이각막형태검사기분석이나 surface regul arity index 및 surface asymmetry index 를이용하였으며, 18-20 파면수차계를이용하여고위수차를분석한경우는없었다. Pesudovs and Figueiredo 15 가각막형태검사기를이용하여군날개수술전후의고위수차값을분석하였는데군날개크기가클수록절제후남게되는수차또한커짐을상대적위험도를이용하여나타내었고, 상대적위험도가군날개크기 4 mm~5 mm 에서가장크게나타나군날개크기 4 mm 이하일때수술하는것이바람직하다고보고하였다. Lin and Stern 21 도군날개환자에서각막형태검사기를이용하여난시의변화를관찰하였으며군날개가각막반경의 45% 를넘어서침범했거나시축으로부터 3.2 mm 이내에병변이있을경우군날개크기에비례하여난시가증가한다는사실을보고하였다. 군날개의발생은각막의비대칭적인직난시를유발할수있으며 Ozdemir and Cinal 22 은군날개수술후술전과벡터분석을통하여수술전 81% 의직난시를보이던것이수술후에는 44% 에서 oblique 와 38% 에서도난시로나타남을보고하였고, 술후초기에는 3.23D (diopter) 의벡터변화가생겼으나술후후기에는 2.70D (diopter) 로벡터변화가줄어들어술후에도난시축이변화되기때문이라고하였다. 수술후난시축의변화는군날개절제술후각막만곡도의복원에있어수평만곡도의증가가수직만곡도의증가보다커지기때문이며, 이런한난시축의변화는군날개크기 3 mm 이상군에서두드러지게나타났으며시간이지날수록각막조직의재생과정및조직학적재형성으로 1742
대한안과학회지 2008 년제 49 권제 11 호 Table 3. Summary of mean value and standard deviation of high order aberrations with wavefront aberrometer before and after pterygium surgery (wave front aberrometer pupil size=4.0 mm) Mean±SD (RMS, µm) Pre op 1 Wk 1 Mo 3 Mo p-value Preop vs 1 Wk Preop vs 1 Mo Preop vs 3 Mo Pterygium size < 3 mm (4.0 mm*) Coma aberration Spherical aberration Total aberration 0.74 ±0.54 0.52 ±0.35 2.13 ±1.56 0.42 ±0.41 0.34 ±0.24 1.47 ±1.31 0.31 ±0.32 0.31 ±0.15 1.38 ±1.45 0.28 ±0.24 0.23 ±0.16 1.12 ±1.18 Pterygium size 3 mm (4.0 mm*) Coma aberration Spherical aberration Total aberration 1.17±1.57 0.64±0.51 3.16±1.69 0.82±1.23 0.52±0.52 2.47±1.83 0.64±0.62 0.38±0.37 1.95±1.86 0.47±0.40 0.32±0.31 1.86±1.54 0.03 * Pupil size in wavefront aberrometer; Wilcoxon signed rank test for each aberration; Zernike total high order aberration; SD=standard deviation. 난시축이다시변화하는것으로알려져있다. 9,23 저자들도마찬가지로군날개크기 3 mm 이상군에서술전직난시가군날개절제후초기에도난시나 oblique 로난시축이변화됨을알수있었으며군날개에의해유발된난시는군날개절제후감소하게되며변화되는양상을난시벡터분석을통하여 B (length of vector) 값과난시벡터의산포도로나타내었다. 저자들은연구결과 B 값은군날개크기에상관없이술후모두의미있게감소함을보고했으나난시벡터 (J 0, J 45 ) 의분석에서군날개크기에따라차이를보인것은군날개에의해발생한비측의편평한각막만곡도는군날개절제술직후변하게되며군날개크기 3 mm 미만군에선수술후에도남아있던편평한각막만곡도가점차회복되어이로인해난시벡터의산포도에서술전산발적으로분포되어있던양상이술후점차 (0,0) 점을향해모이게되며, 군날개크기가큰 3 mm 이상군에선군날개절제후남아있던편평한각막만곡정도가변하지않고남게될가능성이커난시벡터의산포도에서시간이지나도산발적으로분포하는원인으로생각되어진다. 저자들은각막형태검사기를이용한난시벡터분석뿐아니라다른연구에서시도되지않았던파면수차계를이용하여안구전체에대한군날개수술전후의고위수차변화를알아보았으며, 군날개수술후코마수차, 구면수차, 전체수차에서술전과비교하여고위수차값이의미있게감소함을알수있었다. 군날개크기 3 mm 미만과이상모두술전과비교하여술후의미있는고위수차값의감소를보였지만두군의변화율을비교해 보면코마수차와구면수차및전체수차모두에서술전에대한술후 1 주째변화율이군날개크기 3 mm 미만군에서 3 mm 이상군에비하여의미있게변화율이커짐을알수있었다. 저자들은파면수차계측정시 Pupil size 6.5 mm zone 의고위수차를비교해보았으며 3 mm 이상의군날개의경우측정범위 (pupil size=6.5 mm) 를고려할때군날개자체로인해생기는측정시오차가더욱반영되었을가능성이있어 Pupil size 4.0 mm zone 으로측정하여고위수차를알아보았으며전체적으로 6.5 mm zone 으로측정시보다고위수차값이적어짐을알수있었다 (Table 3). 이것은 6.5 mm zone 으로측정시군날개가가리고있는면적에의해수술전후측정시반영된결과일가능성이있다. 하지만 4.0 mm zone 의측정시에도고위수차모두에서술전에대한술후 1 주째변화율이군날개크기 3 mm 미만군에서 3 mm 이상군에비하여의미있게변화율이커짐을알수있었다. 군날개크기에따른수술의시기는저자들마다다양하게보고되고있지만, 대부분에서적절한시기에해야만난시의변화를줄일수있으며시력또한향상될수있다고보고하고있으며, 24,25 본연구에서도군날개크기 3 mm 이상에비하여 3 mm 미만에서술후난시벡터의유의한개선및고위수차변화율이더크게나타났기때문에보다효과적인난시와고위수차의개선을위해선 3 mm 미만에서수술을고려하는것이바람직할것으로사료된다. 군날개수술전후의파면수차계의측정은저자들에의해처음 1743
권상민외 : 군날개수술전후고위수차의변화 으로시도되었으며고위수차분석에있어저니케다항식 (Zernike polynomial expansion) 을이용하였다. 아직까지본연구와비교대상이부족하여본연구결과에대한논의와군날개등안질환에있어저니케다항식의적용이 26,27 적합한지좀더연구가필요할것으로사료된다. 참고문헌 1) Reinstrow SD. The conjunctiva. In : Podos SM, Yanoff M, eds. Textbook of Ophthalmology, first ed. London: Mosby- Wolfe, 1995: v. 1. chap. 2. 2) Lindsay RG, Sullivan L. Pterygium-induced corneal astigma tism. Clin Exp Optom 2001;84:200-3. 3) Avisar R, Loya N, Yassur Y, Weinberger D. Pterygiuminduced corneal astigmatism. Isr Med Assoc J 2000;2:14-5. 4) Kampitak K. The effect of pterygium on corneal astigmatism. J Med Assoc Thai 2003;86:16-23. 5) Walland MJ, Stevens JD, Steele AD. The effect of recurrent pterygium on corneal topography. Cornea 1994;13:463-4. 6) Hansen A, Norn M. Astigmatism and surface phenomena in pterygium. Acta Ophthalmol 1980;58:174-81. 7) Gridley MJ, Perlman EM. A form of variable astigmatism induced by pseudopterygium. Ophthalmic Surg 1986;17:794-795. 8) Oldenburg JB, Garbus J, McDonnell JM, McDonnell PJ. Conjunctival pterygia: mechanism of corneal topographic changes. Cornea 1990;9:200-4. 9) Kang SW, Cho BJ. Changes in the corneal curvature and recurrence rate following pterygium surgery with relation to pterygium size and morphology. J Korea Ophthalmol Soc 2001;42:1255-64. 10) Soriano JM, Janknecht P, Witschel H. Effect of pterygium operation on preoperative astigmatism: prospective study. Ophthalmologe 1993;90:688-90. 11) Budak K, Khater TT, Friedman NJ, Koch DD. Corneal topographic changes induced by excision of perilimbal lesions. Ophthalmic Surg Lasers 1999;30:458-64. 12) Stern GA, Lin A. Effect of pterygium excision on induced corneal topographic abnormalities. Cornea 1998;17:23-7. 13) Oh JR, Kim JS, Lee DH. The change of ocular aberration after LASIK surgery. J Korea Ophthalmol Soc 2003;44:278-83. 14) Roberts C. The cornea is not a piece of plastic. J Refract Surg 2000;16:407-13. 15) Pesudovs K, Figueiredo FC. Corneal first surface wavefront aberrations before and after pterygium surgery. J Refract Surg 2006;22:921-5. 16) Oner FH, Kaderli B, Durak I, Cingil G. Analysis of the pterygium size inducing marked refractive astigmatism. Eur J Ophthalmol 2000;10:212-4. 17) Thibos LN, Horner D. Power vector analysis of the optical outcome of refractive surgery. J Cataract Refract Surg 2001; 27:80-5. 18) Tomidokoro A, Miyata K, Sakaguchi Y, et al. Effects of pterygium on corneal spherical power and astigmatism. Ophthalmology 2000;107:1568-71. 19) Bahar I, Loya N, Weinberger D, Avisar R. Effect of pterygium surgery on corneal topography: a prospective study. Cornea 2004;23:113-7. 20) Yagmur M, Ozcan AA, Sari S, Ersöz TR. Visual acuity and corneal topographic changes related with pterygium surgery. J Refract Surg 2005;21:166-70. 21) Lin A, Stern GA. Correlation between pterygium size and induced corneal astigmatism. Cornea 1998;17:28-30. 22) Ozdemir M, Cinal A. Early and late effects of pterygium surgery on corneal topography. Ophthalmic Surg Laser Imaging 2005;36:451-6. 23) Hong JW, Lee TS. Comparison of refractive change measured by corneal topography between before and after pterygium excision. J Korea Ophthalmol Soc 1996;37:1614-9. 24) Maheshwari S. Pterygium-induced corneal refractive changes. Indian J Ophthalmol 2007;55:383-6. 25) Avisar R, Loya N, Yassur Y, Weinberger D. Pterygiuminduced corneal astigmatism. Isr Med Assoc J 2000;2:14-5. 26) Smolek MK, Klyce SD. Zernike polynomial fitting fails to represent all visually significant corneal aberrations. Invest Ophthalmol Vis Sci 2003;44:4676-81. 27) Klyce SD, Karon MD, Smolek MK. Advantages and disadvantages of the Zernike expansion for representing wave aberration of the normal and aberrated eye. J Refract Surg 2004;20:S537-41. 1744
대한안과학회지 2008 년제 49 권제 11 호 =ABSTRACT= Power Vector and Aberrations Using Corneal Topographer and Wavefront Aberrometer Before and After Pterygium Surgery Sang Min Kwon, M.D., Dong Joon Lee, M.D., Woo Jin Jeung, M.D., Woo Chan Park, M.D. Department of Ophthalmology, Dong-A University College of Medicine, Pusan, Korea Purpose: To determine the power vector and aberrations before and after surgery for pterygium using a corneal topographer and a wavefront aberrometer. Methods: The study group consisted of 34 eyes of 31 patients with pterygium, and were divided into two groups by pterygium size (< 3 mm, group I 3 mm, group II). Power vector and wavefront aberrations were evaluated using a corneal topographer (Oculus inc., Germany) and a wavefront aberrometer (LADARWAVE R, Hartmann shack aberrometer, Alcon inc., US) at pre- and postoperative 1 week, 1 month, and 3 months. Results: The preoperative blurring strength (B) and high order aberrations significantly decreased at postoperative 3 months in all groups (P<0.05). Power vector scattergraphs showed the cluster of points gathered around the zero point in group I, but not in group II at postoperative month three. The change rates of high order aberrations were significantly greater in group I than in group II in the preoperative period compared to the postoperative first week period. Conclusions: Improvements of the power vector and high order aberrations were more remarkable in group I (< 3 mm) than in group II ( 3 mm). To reduce aberrations and astigmatism effectively, we suggested surgical intervention in eyes with pterygia sized < 3.0 mm. J Korean Ophthalmol Soc 2008;49(11):1737-1745 Key Words: Corneal topographer, High order aberrations, Power vector analysis, Wavefront aberrations, Wavefront aberrometer Address reprint requests to Woo Chan Park, M.D. Department of Ophthalmology, Dong-A University College of Medicine #3-1 Dongdaesin-dong, Seo-gu, Pusan 602-714, Korea Tel: 82-51-240-5227, Fax: 82-51-254-1987, E-mail: wcpark@dau.ac.kr 1745