대한안과학회지 2015 년제 56 권제 4 호 J Korean Ophthalmol Soc 2015;56(4):532-540 ISSN 0378-6471 (Print) ISSN 2092-9374 (Online) http://dx.doi.org/10.3341/jkos.2015.56.4.532 Original Article 백내장종류에따른안내수차의패턴분석 Analysis of Internal Optical Aberrations in Eyes with Different Types of Cataract 한지윤 엄영섭 임재원 강수연 김효명 송종석 Ji Yun Han, MD, Young Sub Eom, MD, Jay Won Rhim, MD, Su Yeon Kang, MD, Hyo Myung Kim, MD, PhD, Jong Suk Song, MD, PhD 고려대학교의과대학안과학교실 Department of Ophthalmology, Korea University College of Medicine, Seoul, Korea Purpose: The present study investigates the patterns of internal optical aberrations in eyes with different types of cataract. Methods: Eighty eyes of 70 cataract patients were included in the present study. Internal optical aberrations were measured with a KR-1W wavefront aberrometer before cataract operation. Types of cataract were classified into three groups; cortical, nuclear and posterior subcapsular cataracts. The differences in the results of the wavefront data of 6-mm pupil diameter zones were compared among three groups. The Kruskal-Wallis test and Mann-Whitney U test were used for comparing data. Results: A total of 80 eyes consisting of 30 cortical cataracts, 30 nuclear cataracts and 20 posterior subcapsular cataracts were found. In the 6-mm pupil diameter zone, the average internal spherical aberrations by original value were 0.042 μm of cortical cataracts, -0.092 μm of nuclear cataracts and -0.109 μm of posterior subcapsular cataracts. The average internal spherical aberrations by absolute value were 0.122 μm of cortical cataracts, 0.533 μm of nuclear cataracts and 0.202 μm of posterior subcapsular cataracts. The internal spherical aberrations by original value were not statistically significantly different, but by absolute value were statistically significantly different (p = 0.003, Kruskal-Wallis test). Nuclear cataracts have a much higher positive or negative value than other cataract groups in the distribution of internal spherical aberrations by original value for each type of cataract. Other than this difference, the internal astigmatism and internal high order aberrations were not statistically significantly different. Conclusions: The change in internal spherical aberrations of nuclear cataract from the original value was larger than cortical and posterior subcapsular cataract. Therefore, nuclear cataracts have much higher positive or negative values than other cataract groups. J Korean Ophthalmol Soc 2015;56(4):532-540 Key Words: Different types of cataract, Internal optical aberrations, Internal spherical aberrations Received: 2014. 7. 21. Revised: 2015. 2. 12. Accepted: 2015. 3. 24. Address reprint requests to Jong Suk Song, MD, PhD Department of Ophthalmology, Korea University Guro Hospital, #148 Gurodong-ro, Guro-gu, Seoul 152-703, Korea Tel: 82-2-2626-3178, Fax: 82-2-857-8580 E-mail: crisim@korea.ac.kr * This study was presented as a narration at the 110th Annual Meeting of the Korean Ophthalmological Society 2013. * This study was partially supported by the Korea University Ophthalmology Alumni Fund. 빛번짐, 눈부심, 대비감도감소등에따른시기능저하가단순굴절이상만으로는충분히설명하기에부족하며, 고위수차와연관성이있다는연구들이보고됨에따라백내장수술후시력향상및환자의만족도에있어고위수차의중요성은점점증가하고있다. 1-6 노화에따른안구수차의변화에대한이전연구에서연령이증가할수록안구구면수차 (ocular spherical aberration) 와안구코마 (ocular coma) 값이증가하는데, 이러한변화중안구구면수차의증가는주로안내구면수차 c2015 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. 532
- 한지윤외 : 백내장종류별안내수차패턴분석 - (internal spherical aberration) 변화에의해나타나며, 안구코마값의증가는주로각막코마 (corneal coma) 값의변화에의해나타난다고하였다. 7 또한백내장환자에서고위수차를비교한이전연구에서피질백내장 (cortical cataract) 의경우안구코마값이우세하고, 핵백내장 (nuclear cataract) 에서는안구구면수차값이우세하다고보고하였다. 8 그러나기존의연구들은안구의전체수차를평가하거나각막의수차만을평가한경우가대부분이었고, 수정체의변화나백내장자체에의해좀더실제적인변화를보일수 있는안내수차를평가하지않아, 백내장의종류에따라안내수차가어떻게달라지는지에대한연구는부족한실정이다. 따라서, 본연구에서는안구전체와각막의수차는물론이두값을이용하여안내수차에대한정보를따로제시하는 KR-1W 수차계를이용하여백내장종류에따라안내수차의양상에어떠한차이가있는지알아보고자하였다. A B C Figure 1. A case of posterior subcapsular cataract that was completely examined all of the aberration data using KR-1W. (A) A slit photo showed a posterior subcapsular cataract (NO1, NC2, C1, P4 in LOCS III score). (B) A photo with retroillumination. (C) The result of KR-1W wavefront aberrometer in this case. Astig = astigmatism; HOA = high order aberrations. 533
- 대한안과학회지 2015 년제 56 권제 4 호 - 대상과방법 본연구는후향적연구로서 2011년 8월부터 2013년 3월까지본원에백내장수술을받고자내원한환자중수술전검사로 KR-1W 수차계 (Topcon Corp., Tokyo, Japan) 를이용하여안내수차를측정한 70명 80안을대상으로의무기록을분석하였다. 백내장의분류는피질과후낭하혼탁을 5단계, 핵을혼탁과색조에따라서각기 6단계로분류한 lens opacities classification system III (LOCS III) 9 을기준으로하여피질백내장, 핵백내장, 후낭하백내장세그룹으로분류하였다. 피질백내장은 C3 이상이면서 NO2, NC2 이하인경우를대상으로하였고, 핵백내장은 NO3, NC3 이상이면서 C2 이하인경우를대상으로하였다. 또한후낭하백내장은 P3 이상이면서 N2, C2 이하인경우를대상으로하였으며, 모든그룹에서 P1, P2인경우는제외하였다. KR-1W 안구수차계는 Hartmann Shack 방식으로황반부에조사된레이저가반사되어눈을통과하여나올때발생하는수차를바둑판모양의렌즈군과 charge-coupled device (CCD) 에서동시에기록함으로써수차를측정한다. 또한각막지형도를이용하여동시에각막의수차를측정하고, 같은중심축을기준으로측정한전체안구의수차와각막의 수차를이용하여안내수차를계산하여나타낸다. 10,11 이검사는산동제 (phenylephrine chloride 0.5% + tropicamide 0.5%) (Mydrin-P, Santen, Osaka, Japan) 를 10분간격으로 3 회점안하여산동한후외부빛이유입되지않는암실에서측정하였으며, 이를통해얻은동공지름 6 mm 범위에서의안내수차값이백내장종류에따라어떠한차이를보이는지알아보았다. 이때안구수차와각막수차, 안내수차중어느하나라도측정이되지않은경우는모두제외하고, 모든결과가정확히측정된데이터만포함하였다 (Fig. 1). 자료의통계분석은 SPSS 12.0 (SPSS Inc., Chicago, IL, USA) 을이용하였으며얻어진자료가정규분포를하지않는것으로나타나독립표본비모수검정방법으로분석하였다. 세그룹간의비교는 Kruskal-Wallis test를이용하였고, 세그룹간비교에서유의한차이가있는경우에 Mann-Whitney U test 를이용하여두그룹씩각각비교하였다. p값이 0.05 미만인경우통계적으로유의한차이가있는것으로간주하였다. 결과 총 70명 80안의백내장환자가본연구에포함되었으며, 이들의평균연령은 59.08 (±8.73) (range, 32-88) 세였고남성이 23안 (22명), 여성이 57안 (48명) 이었다. 백내장종류에 Table 1. Demographic characteristics Sex (M/F) (number of eyes, patients) 23 (22)/57 (48) Total mean age ± SD (years, range) 59.08 ± 8.73 (32-88) Type of cataract No. of eyes (mean age ± SD) p-value * Cortical opacity 30 (59.13 ± 5.077) 0.808 Nuclear opacity 30 (59.43 ± 10.04) Posterior subcapsular opacity 20 (58.45 ± 11.11) * Kruskal-Wallis test (p < 0.05 significant). Table 2. The average of internal astigmatism and internal high order aberrations on 6-mm diameter zone (root mean square value) Astig. Total HOA 3rd order HOA 4th order HOA Trefoil Coma Tetrafoil 2nd Astig. CO -0.9467 0.566 0.403 0.283 0.280 0.272 0.182 0.139 NS -1.097 0.884 0.526 0.650 0.223 0.451 0.170 0.175 PSCO -1.1375 0.708 0.524 0.355 0.254 0.402 0.136 0.191 p-value 0.343 0.280 0.728 0.031 0.644 0.215 0.087 0.868 The internal astigmatism and internal high order aberrations were not statistically significantly different except for 4th order high order aberrations. Astig = astigmatism; HOA = high order aberrations; CO = cortical opacity; NS = nuclear sclerosis; PSCO = posterior subcapsular opacity. Table 3. The average of internal spherical aberrations by original value and absolute value on 6-mm diameter zone CO NS PSCO p-value Internal SA (original, μm) 0.042-0.092-0.109 0.053 Internal SA (absolute, μm) 0.122 0.533 0.202 0.003 The internal spherical aberrations by original value were not statistically significantly different, but by absolute value were statistically significantly different. SA = spherical aberrations; Absolute = absolute value; Original = original value; CO = cortical opacity; NS = nuclear sclerosis; PSCO = posterior subcapsular opacity. 534
- 한지윤외 : 백내장종류별안내수차패턴분석 - Figure 2. The average of internal astigmatism and internal high order aberrations on 6-mm diameter zone. The internal astigmatism and internal high order aberrations were not statistically significantly different except for 4th order high order aberrations (p = 0.031, Kruskal-Wallis test). Astig = astigmatism; HOA = high order aberrations; CO = cortical opacity; NS = nuclear sclerosis; PSCO = posterior subcapsular opacity. * p < 0.05 based on Kruskal-Wallis test. A B Figure 3. The average of internal spherical aberrations by original value and absolute value on 6-mm diameter zone. SA = spherical aberrations; Absolute = absolute value; Original = original value; CO = cortical opacity; NS = nuclear opacity; PSCO = posterior subcapsular opacity. * p < 0.017 based on Bonferroni-corrected post hoc Mann-Whitney U test. (A) The internal spherical aberrations by original value were not statistically significantly different. (B) The internal spherical aberrations by absolute value were statistically significantly different. Table 4. The internal spherical aberrations by absolute value were statistically significantly different between cataract group of cortical opacity and nuclear opacity CO vs NS NS vs PSCO CO vs PSCO p-value * 0.001 0.043 0.347 The internal spherical aberrations by absolute value were not statistically significantly different between cataract group of nuclear opacity and posterior subcapsular opacity, cortical opacity and posterior subcapsular opacity. CO = cortical opacity; NS = nuclear sclerosis; PSCO = posterior subcapsular opacity. * Bonferroni-corrected post hoc Mann-Whitney U test for comparisons between two groups (p < 0.017 significant). 따른분류는피질백내장 30안, 핵백내장 30안, 후낭하백내장 20안이었고, 그룹간연령별차이는없었다 (Table 1). 동공지름 6 mm 범위에서안내난시 (Internal Astigmatism) 및고위수차 (High order aberrations) 값은세그룹간에비교했을때 4차고위수차만통계적으로유의한차이를보였으며, 그외에는유의한차이를보이지않았다 (Table 2) (Fig. 2). 안내구면수차 (Internal spherical aberrations) 값은고유값으로비교했을때음성과양성의값이존재하여세그룹간에유의한차이가없었지만, 고유값을절대값으로바꾸어비교했을때는통계적으로유의한차이를보였다 (Table 3) (Fig. 3). 또한절대값으로두그룹씩다시비교했을때피질백내장과핵백내장간에는유의한차이를보였 535
- 대한안과학회지 2015 년제 56 권제 4 호 - Figure 4. The distribution of internal spherical aberrations by original value for each type of cataract. 지만, 핵백내장과후낭하백내장, 피질백내장과후낭하백내장간에는유의한차이가없었다 (Table 4). 그룹별안내구면수차의비교를고유값으로했을때는차이가없었으나절대값으로했을때핵백내장에서유의하게높은소견을보여, 각백내장종류에따라안내구면수차의고유값분포를그래프로나타낸결과 (Fig. 4) 큰양이나음의값을보인경우는대부분핵백내장으로, ±0.5 μm 이상인경우가피질백내장은 0%, 핵백내장 33.3% (10 안 /30 안 ), 후낭하백내장 15% (3안/20안) 로핵백내장에서높은양의값이나높은음의값을보이는경우가통계적으로유의하게더많았다 (p=0.002, Kruskal-Wallis test). 고 찰 수차는렌즈등의광학계에서상을맺을때원거리에서오는평행광선은광학계를지난다음한점에맺혀야하지만, 한점에모이지않아빛번짐이있거나일그러져보이는현상을말하며, 12 고위수차는일반안경이나콘택트렌즈로교정이불가능한모든굴절이상또는불규칙난시를일컫는용어로코마 (coma), 트레포일 (trefoil), 구면수차 (spherical aberration) 등의용어와 Zernike 계수로표현된다. 13 고위수차와관련한이전연구를보면, Applegate et al 2,14 은 Zernike 표의중심부에가까운수차 ( 코마, 구면수차, 2차난시 (2nd astigmatism) 등 ) 일수록 Zernike 표주변부에있는수차보다물체의상이왜곡되어보이고, 시력의질이저하되는데더큰영향을미친다고보고하였고, Amano et al 7 은연령이증가할수록안구구면수차와안구코마값모두증가하는데, 안구구면수차는각막구면수차보다주로수정체혼탁에의한안내구면수차변화와연관이있으며, 안구코마값은안내코마값보다주로노화에따른각막의변화와더연관이있다고보고하였다. 또한 Rocha et al 8 은백내장종류에따라피질백내장에서안구코마값이우세하며, 핵백내장에서안구구면수차값이더우세하다고하였다. 본연구에서는동공지름 6 mm 범위에서안내난시및고위수차값을백내장종류에따른세그룹으로나눠비교했을때 4차고위수차만이통계적으로유의한차이를보였으며, 그외에코마, 구면수차, 2차난시등다른항목에서는유의한차이를보이지않았다. 본연구에서코마값이유의한차이를보이지않은것은코마가각막의변화와더연관이있다는기존의연구결과로미루어보아안구수차에서각막수차의값을뺀안내수차값만을비교했기때문이라고생각한다. 또한구면수차와관련한기존연구들을보면, Kuroda et al 15 은핵백내장 6안과피질백내장 18안, 백내장이없는정상안 9안을대상으로한연구에서핵백내장에서단일고위수차값으로가장우세한것은구면수차이며, 그룹별로안구구면수차 (Ocular spherical aberrations) 값을비교한결과대부분양의값을보인정상안이나피질백내장과는달리모든핵백내장환자에서구면수차값이평균 -1.274 ± 0.733 μm로전부음의값을보인다고하였고, Lee et al 16 은 33안을대상으로하여연령에따라핵백내장의 grade는증가하였고, 안내구면수차의평균값은 -0.38 ± 0.86 μm로핵백내장의 grade가증가할수록안내구면수차값은감소하는음의상관관계를보인다고하였다 (r=-0.450, p=0.009). 하지만이러한연구들과달리, Alió et al 17 은정상안 72안을대상으로한연구에서안내구면수차는양의값을보인경우와음의값을보인경우둘다있었지만, 연령이증가할수록안내구면수차값이증가하는양상의양의상관관계를보인다고하였고 (r=0.382, p=0.001), Sachdev et al 18 은경도에서중등도사이의핵백내장 10안, 피질백내장 10안, 정상안 20안을대상으로하여핵백내장에서가장우세한고위수차가구면수차이며, 안내구면수차의평균값이핵백내장 0.518 ± 0.486 μm, 정상안 0.150 ± 0.124 μm로핵백내장에서정상안에비해통계적으로유의하게더큰안내구면수차값을가진다고하였다. 이는앞서언급한논문들과비교했을때핵백내장에서구면수차가가장우세한고위수차라는연구결과는비슷하게나왔지만, 구면수차가양의값또는음의값중어떤값을보이는지와연령과백내장 grade와의상관관계등에있어서는상반된결과를나타내 536
- 한지윤외 : 백내장종류별안내수차패턴분석 - A B Figure 5. A case of nuclear cataract that had highly negative spherical aberration. The HOA map of ocular wavefront shows a delay of light (cool color) in the central pupillary area. In the color-coded map, cool color represents relatively delayed wavefront and a warm color represents relatively advanced wavefront. (A) A slit photo showed a nuclear cataract (NO4, NC4, C1 in LOCS III score). (B) The result of KR-1W wavefront aberrometer in this case. HOA = high order aberrations. 고있다. 본연구에서는백내장종류에따른세그룹간에안내구면수차의평균을고유값으로비교했을때는유의한차이가없었으나, 절대값으로비교했을때는핵백내장에서피질백내장이나후낭하백내장그룹에비해통계적으로유의하게더큰평균값을보이며, 핵백내장에서다른그룹에비해안내구면수차값이상대적으로더높은양의값또는음의값을보이는경우가많았다. 핵백내장그룹에서안내구면수차가 ±0.5 μm보다높은양의값과음의값을보이는경우를살펴보면, 먼저높은음의값을보이는경우는색코 드지도상에서중심부가청색계열, 주변부가적색계열로나타나는데이는핵경화가동공중심부쪽에심하여주변부에비해상대적으로파동진행이느려지기때문이라생각한다 (Fig. 5). 15 또한높은양의값을보이는경우는핵경화가중심부에국한되지않고수정체주변부까지생겨색코드지도상에서청색계열이주변부에나타나는것을볼수있는경우였다 (Fig. 6). 따라서기존연구들에서안내구면수차에대해상반된결과를보였던것은수정체의핵경화상태에따라안내구면수차가양의값또는음의값으로변하기때문이라생각한다. 537
- 대한안과학회지 2015 년제 56 권제 4 호 - A B Figure 6. A case of nuclear cataract that had highly positive spherical aberration. The HOA map of ocular wavefront shows a delay of light (cool color) in the periphery. (A) A slit photo showed a nuclear cataract (NO5, NC5, C2 in LOCS III score). (B) The result of KR-1W wavefront aberrometer in this case. HOA = high order aberrations. Dubbelman et al 19,20 은조절과정에서수정체중심부의상대적비대와수정체앞면의곡률반경의변화가구면수차의변화에영향을미친다고보고한바있고, Yoo et al 21 은정상인을대상으로하여동공지름 6 mm 범위에서산동전후각막구면수차값은차이가없었으나, 안구와안내구면수차는산동후에유의하게음의방향으로증가하였으며이는산동제의조절마비효과에의해수정체표면이원뿔곡선형 (conoid shape) 으로변화하기때문이라고보고하였다. 본연구에서는환자에따라서동공의크기가 6 mm보다작아동공지름 6 mm 범위의수차값이측정되지않을수있어산동을시행한후측정을하였으며, 산동이안내구면수차에영향을미칠수있지만세그룹간평균연령의 차이가없어조절에의한영향이어느한그룹에더많이영향을주지않았으리라생각한다. 본연구의한계점으로는백내장을분류하는데있어서후향적으로의무기록에따라세가지백내장종류중가장영향이있다고판단되는백내장종류로분류하였다는점이다. 피질, 핵, 후낭하혼탁이모두심하게있는경우는연구의대상에서제외하였으나, 본대상중분류된형태이외의다른부분의혼탁이고위수차를분석하는데다소영향을줄수있으리라생각을한다. 또한안내수차분석에있어각막후면의영향이있을수있으나각막후면수차에대한분석이따로이루어지지않았고, 그룹별대상환자수가 20 안또는 30안으로비교적적다는점, 백내장그룹과비교할 538
- 한지윤외 : 백내장종류별안내수차패턴분석 - 수있는정상안그룹이없다는점, 난시평가에서난시축에대한고려가없었다는점이이연구의제한점이라고할수있다. 결론적으로, 안내구면수차가높은양의값이나음의값을가질경우백내장혼탁에있어핵경화의분포상태를예측하는데참고하는데이터로이용할수있을것이라생각하며, 추후더많은환자를대상으로백내장혼탁의중증도와안내수차와의상관관계에대한연구도이루어진다면임상적으로더가치가있을것으로생각한다. REFERENCES 1) Porter J, Guirao A, Cox IG, Williams DR. Monochromatic aberrations of the human eye in a large population. J Opt Soc Am A Opt Image Sci Vis 2001;18:1793-803. 2) Applegate RA, Marsack JD, Ramos R, Sarver EJ. Interaction between aberrations to improve or reduce visual performance. J Cataract Refract Surg 2003;29:1487-95. 3) Kuroda T, Fujikado T, Ninomiya S, et al. Effect of aging on ocular light scatter and higher order aberrations. J Refract Surg 2002;18: S598-602. 4) Donnelly WJ 3rd, Pesudovs K, Marsack JD, et al. Quantifying scatter in Shack-Hartmann images to evaluate nuclear cataract. J Refract Surg 2004;20:S515-22. 5) Marcos S. Aberrations and visual performance following standard laser vision correction. J Refract Surg 2001;17:S596-601. 6) Tomidokoro A, Soya K, Miyata K, et al. Corneal irregular astigmatism and contrast sensitivity after photorefractive keratectomy. Ophthalmology 2001;108:2209-12. 7) Amano S, Amano Y, Yamagami S, et al. Age-related changes in corneal and ocular higher-order wavefront aberrations. Am J Ophthalmol 2004;137:988-92. 8) Rocha KM, Nosé W, Bottós K, et al. Higher-order aberrations of age-related cataract. J Cataract Refract Surg 2007;33:1442-6. 9) Chylack LT Jr, Wolfe JK, Singer DM, et al. The Lens Opacities Classification System III. The Longitudinal Study of Cataract Study Group. Arch Ophthalmol 1993;111:831-6. 10) Piñero DP, Juan JT, Alió JL. Intrasubject repeatability of internal aberrometry obtained with a new integrated aberrometer. J Refract Surg 2011;27:509-17. 11) Jeong JH, Kim MJ, Tchah HW. Clinical comparison of laser ray tracing aberrometer and shack-hartmann aberrometer. J Korean Ophthalmol Soc 2006;47:1911-9. 12) Artal P, Guirao A, Berrio E, Williams DR. Compensation of corneal aberrations by the internal optics in the human eye. J Vis 2001;1:1-8. 13) Artal P, Guirao A. Contributions of the cornea and the lens to the aberrations of the human eye. Opt Lett 1998;23:1713-5. 14) Applegate RA, Sarver EJ, Khemsara V. Are all aberrations equal? J Refract Surg 2002;18:S556-62. 15) Kuroda T, Fujikado T, Maeda N, et al. Wavefront analysis in eyes with nuclear or cortical cataract. Am J Ophthalmol 2002;134:1-9. 16) Lee J, Kim MJ, Tchah H. Higher-order aberrations induced by nuclear cataract. J Cataract Refract Surg 2008;34:2104-9. 17) Alió JL, Schimchak P, Negri HP, Montés-Micó R. Crystalline lens optical dysfunction through aging. Ophthalmology 2005;112:2022-9. 18) Sachdev N, Ormonde SE, Sherwin T, McGhee CN. Higher-order aberrations of lenticular opacities. J Cataract Refract Surg 2004; 30:1642-8. 19) Dubbelman M, Van der Heijde GL, Weeber HA. Change in shape of the aging human crystalline lens with accommodation. Vision Res 2005;45:117-32. 20) Dubbelman M, Van der Heijde GL, Weeber HA, Vrensen GF. Changes in the internal structure of the human crystalline lens with age and accommodation. Vision Res 2003;43:2363-75. 21) Yoo EJ, Kang SY, Kim HM, Song JS. The effects of pharmacologic pupil dilatation on ocular, corneal, and internal aberrations. J Korean Ophthalmol Soc 2013;54:581-6. 539
- 대한안과학회지 2015 년제 56 권제 4 호 - = 국문초록 = 백내장종류에따른안내수차의패턴분석 목적 : 안구의전체수차가아닌수정체의변화에의해주로나타나는안내수차를이용하여백내장종류에따라어떠한차이가있는지알아보고자하였다. 대상과방법 : 백내장수술을받고자내원한환자 70 명 80 안을대상으로수술전검사로 KR-1W 수차계를이용하여안내수차를측정한환자에서백내장종류 ( 피질백내장, 핵백내장, 후낭하백내장 ) 에따라동공지름 6 mm 범위에서의안내수차의값과그수치의절대값을독립표본비모수검정을통해비교하여그차이를알아보았다. 결과 : 전체 80 안중피질백내장 30 안, 핵백내장 30 안, 후낭하백내장 20 안이었고, 동공지름 6 mm 범위에서안내구면수차의고유값평균은피질백내장 0.042 μm, 핵백내장 -0.092 μm, 후낭하백내장 -0.109 μm 로통계적으로유의한차이를보이지않았으나, 절대값으로비교했을때는피질백내장 0.122 μm, 핵백내장 0.533 μm, 후낭하백내장 0.202 μm 로핵백내장이다른두백내장에비해유의하게더컸다 (p=0.003, Kruskal-Wallis test). 또한백내장그룹별로안내구면수차의분포를보았을때높은양의값또는음의값을갖는경우는대부분핵백내장이었다. 그외에안내난시나코마등다른고위수차값은통계적으로유의한차이를보이지않았다. 결론 : 백내장의종류에따라안내구면수차값을비교한결과핵백내장의경우피질백내장이나후낭하백내장에비해안내구면수차값의변화가컸고, 높은양의값이나높은음의값을갖는경우가많았다. < 대한안과학회지 2015;56(4):532-540> 540