대한안과학회지 2015 년제 56 권제 10 호 J Korean Ophthalmol Soc 2015;56(10):1599-1603 ISSN 0378-6471 (Print) ISSN 2092-9374 (Online) http://dx.doi.org/10.3341/jkos.2015.56.10.1599 Original Article 근원거리사시각이차이나는감각외사시의수술결과 Surgical Outcome of Sensory Exotropia with Distant-Near Disparity 원훈재 김대희 임현택 Hun Jae Won, MD, Dae Hee Kim, MD, Hyun Taek Lim, MD, PhD 울산대학교의과대학서울아산병원안과학교실 Department of Ophthalmology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea Purpose: To assess clinical features of sensory exotropia with distant-near disparity, surgical outcome, and compare according to amount of medical rectus resection. Methods: Authors retrospectively reviewed medical records of patients of sensory exotropia with follow-up over 6 months. We defined patients with over 10 prism diopter (PD) disparity as distant-near disparity sensory exotropia (DND-XT) and without disparity as basic sensory exotropia (B-XT). First, we analyzed and compared data of visual acuity, cause and age of visual loss, amount of deviation. Second, Surgical failure was analyzed with dividing DND-XT into conventional surgery group as Parks formula and reduced medial rectus resection group in accordance with disparity. Surgical success was defined as less than 10 PD deviation in distant, near fixation. Results: B-XT consisted of 58 patients (40 males) and DND-XT of 33 patient (13 males). There was no significant difference between 2 groups in onset and cause of visual loss, deviation at distant fixation. But, log MAR visual acuity of worse eye was better in DND-XT than B-XT (1.74 ± 0.78, vs. 2.10 ± 0.74, p = 0.039). Average deviation in distant fixation in DND-XT was 46.55 ± 16.59 PD in distant and 14.93 ± 8.91 PD in near fixation. All patients underwent surgery of medial rectus resection and lateral rectus recession and average deviation was 6.83 ± 7.71 PD at distant fixation, 3.02 ± 0.69 PD at near fixation at last follow-up. Among 33 patients, 16 patients underwent conventional amount of surgery and 17 patients with reduced medial rectus resection. In patient with conventional surgery, 9 patients were surgical failure (8 patients of over-, 1 patient of under-correction) but in patient with reduced amount of resection, only 1 patient was under-correction. Conclusions: As a result of medial rectus resection and lateral rectus recession in DND-XT, more surgical failures due to over-correction were observed with conventional resection and higher surgical success was attained in consideration of disparity. J Korean Ophthalmol Soc 2015;56(10):1599-1603 Key Words: Distant-near disparity, Medial rectus resection, Sensory exotropia 한눈의시력이손상되면감각융합이파괴됨으로써사시가발생할수있는데, 이를감각사시 (sensory strabismus) Received: 2015. 4. 10. Revised: 2015. 6. 4. Accepted: 2015. 8. 14. Address reprint requests to Hyun Taek Lim, MD, PhD Department of Ophthalmology, Asan Medical Center, #88 Olympic-ro 43-gil, Songpa-gu, Seoul 05505, Korea Tel: 82-2-3010-3680, Fax: 82-2-470-6440 E-mail: htlim@amc.seoul.kr 라한다. 1 감각이상은원추각막, 2 노인성백내장 3 등의전안부이상, 유리체출혈등의망막질환, 4 굴절이상, 5 선천이상 6 등에의해발생할수있다. 감각사시는 5-6세전에는내사시와외사시가비슷한비율로발생하며, 그이후에는외사시가주로발생하는것으로알려져있다. 1,7-9 감각사시의치료로는일반적으로프리즘안경, 수술을포함한몇가지방법이이용되고있으나주요치료법은외안근수술이다. 10-15 감각외사시에대해서는사시안의내직 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. 1599
- 대한안과학회지 2015 년제 56 권제 10 호 - 근절제및외직근후전술이주로이용되어왔다. 그런데감각외사시중에는근거리와원거리에서의사시각이서로다른유형의외사시가있고이유형사시의치료법에대해서는아직명확한방법이제시되지못해왔다. 대개근거리사시각이원거리사시각에비해적은형태의감각외사시인데일반적인단안외안근절제및후전술을시행하면근거리에서의과교정혹은원거리에서의저교정등수술성공률을높이기어려운문제가있어왔다. 16-21 이에저자들은근원거리사시각이차이나는감각외사시 (distance-near disparity sensory exotropia) 의적정수술법을모색하기위한목적으로본연구를기획하였다. 내직근은근거리사시각에더관여하고, 상대적으로외직근은원거리사시각에더관여한다는가설에근거하여근거리사시각이원거리사시각에비해작은경우내직근수술량을감량하는수술법을적용하였다. 본연구의목적은근원거리사시각이차이나는감각외사시의수술결과를분석하는것이다. 전통적인감각외사시수술술식과내직근수술량을감량한수술술식의성공률을비교하여보다나은수술방법을제안하고자하였다. 대상과방법 본연구는의무기록자료를검토한후향적분석연구이다. 대상자료는 2010년 1월부터 2014년 6월까지서울아산병원안과에서감각외사시로진단받고 6개월이상경과관찰해온환자들의의무기록자료이다. 그중에서근거리와원거리에서의사시각차이가없는경우를 기본감각외사시 (basic sensory exotropia, B-XT), 그리고근거리사시각과원거리사시각이 10PD 이상차이나는경우를 근원거리사시각이차이나는감각외사시 (distance-near disparity sensory exotropia, DND-XT) 라고이름하였다. 대상환자의수술전최대교정시력, 시력저하의원인및시력상실당시의연령, 수술술식, 수술전후제일눈위치에서의근원거리사시각자료를기록, 취합하였다. 근원거리사시각측정은나쁜눈으로중심주시가가능한경우는프리즘교대가림검사로측정하였고, 가능하지않은경우는크림스키법 (Krimsky method) 으로측정하였다. 원거리사시각은 5 m 거리의시표를보게하면서측정하였고근거리사시각은 33 cm 거리에서측정하였다. 크림스키법으로원거리사시각을측정할때에는시차 (parallax) 발생가능성을최소화하기위해, 환자는원거리를주시하도록한상태에서, 검사자는환자의 1 m 앞에위치하여환자의주시안시선축의바로아래에서시선축을가리지않은채로편위안의위치를관찰하여측정하였다. 첫째, B-XT 군과다른 DND-XT 군의임상특징을파악하기위해시력, 시력저하원인, 나이, 사시각크기등기초자료를비교분석하였다. 둘째, 내직근수술량의조정 (modification) 여부에따라 DND-XT 군을다시비조정군과조정군으로나누어수술결과를분석하였다. 수술은저자중책임저자가수행하였는데책임저자는 2012년 6월이전에는원거리최대외사시각을기준으로 Parks formula 22 상의전통적인수술량대로내직근을절제하였고 2012년 6월이후에는근원거리사시각의차이정도에따라내직근수술량을감량하여절제하였다. 근원거리사시각차이가 20PD 이내인경우원거리외사시각에대한 Parks formula보다 1.5 mm 적게, 20PD 초과 30PD 이내의차이인경우 2.0 mm 적게, 그리고 35PD 이상차이나는경우에는 2.5 mm 적게내직근절제술을시행하였다. 비조정군은결국전통적인술식 (Parks formula group) 으로수술한군이고, 조정군은내직근수술량을감량하여수술한군 (reduced resection group) 으로구분하였다. 두군의수술성적을비교하기위하여최종관찰시점에서의수술성공률을조사하여비교하였다. 수술성공의기준은근거리, 원거리에서모두에서 10프리즘디옵터미만의편위를유지하고있는경우로정하였다. 재수술이필요하거나재수술을받은경우는수술실패에포함하였다. 통계분석은 SPSS (version 18.0, SPSS Inc., Chicago, IL, USA) 프로그램을이용하였고, 두군간의비교는 Wilcoxon s signed rank test를사용하여분석하였다. p-value가 0.05 미만인경우를통계적유의수준으로정하였다. 결과 후향적의무기록조회결과 B-XT 군으로 58명 ( 남자 40 명 ), DND-XT 군으로 33명 ( 남자 13명 ) 이추출되었다. 평균나이는 B-XT 군이 40.4 ± 18.8세, DND-XT 군이 37.8 ± 20.1세였다. 한눈시력상실이발생한나이는 B-XT 군에서평균 10.6 ± 16.7세, DND-XT 군에서 16.1 ± 18.0세로두군간의유의한차이는없었다 (p=0.202) (Table 1). 한눈시력상실의원인측면에서는 B-XT 군에서각막혼탁 8명, 시신경병증 8명, 안구파열 7명, 부등시성약시 7명의순이었으며, DND-XT 군에서는시신경병증 6명, 망막박리 6명, 부등시성약시 3명의순이었고역시두군간주목할만한차이를발견할수없었다 (Table 2). 원거리주시때의외사시각의크기면에서두군을비교하면, B-XT 군은평균 48.77 ± 19.31PD, DND-XT 군은평균 46.55 ± 16.59PD로유의한차이가없었다. 최대교정시력면에서는첫째, 좋은눈의시력은두군이각각 0.13 ± 1600
- 원훈재외 : 근원불일치감각외사시의수술결과 - Table 1. Basic characteristics of sensory exotropia with and without distant-near disparity Basic XT DND-XT p-value Patient number 58 33 Age at presentation (years) 40.40 ± 18.77 37.88 ± 20.07 0.533 Male sex (n, %) 40 (68.97) 13 (39.39) Age at visual loss 10.59 ± 16.72 16.12 ± 17.96 0.202 0-1 years (n, %) 6 (10.34) 8 (24.24) 2-8 years (n, %) 18 (31.03) 8 (24.24) Over 9 years (n, %) 25 (43.10) 10 (30.30) Unknown (n, %) 9 (15.52) 7 (21.21) V/A in better eye (log MAR) 0.13 ± 0.30 0.12 ± 0.22 0.970 V/A in worse eye (log MAR) 2.10 ± 0.74 (0.2-LP) 1.74 ± 0.78 (0.4-NLP) 0.039 Amount of distance XT (PD) 48.77 ± 19.31 46.55 ± 16.59 0.725 Values are presented as mean ± SD unless otherwise indicated. Basic-XT = basic sensory exotropia; DND-XT = sensory exotropia with distant-near disparity; V/A = visual acuity; log MAR = logarithm of the minimum angle of resolution; LP = light perception; NLP = non-light perception; XT = exotropia; PD = prism diopter. Table 2. Cause of sensory deficit of sensory exotropia with and without distant-near disparity Basic-SXT DND-SXT Congenital cataract 2 2 Acquired cataract 1 1 Optic neuropathy 8 6 Retinal detachment 6 6 Glaucoma 4 2 Corneal opacities 8 2 Vitreous opacities 2 1 Congenital retinal disorders 3 2 Corneoscleral laceration 7 1 Amblyopia 7 3 Etc. 10 7 Total 58 33 Basic-SXT = basic sensory exotropia; DND-SXT = sensory exotropia with distant-near disparity. 0.30 logmar, 0.12 ± 0.22 logmar로유의한차이가없었으나 (p=0.970), 나쁜눈의시력은각각 2.10 ± 0.74 logmar (0.2-광각), 1.74 ± 0.78 (0.4-무광각) logmar로 DND-XT 군의시력이더좋았다 (p=0.039). 다음은 DND-XT 군에대한세부임상데이터분석결과이다. 평균원거리외사시각이 46.55 ± 16.59PD인데비해근거리사시각은 14.93 ± 8.91PD로그차이는 29.83 ± 19.25PD였다. 이들은모두단안내직근절제및외직근후전술을받았고, 그중조정봉합에의한수술은 14명, 비조정봉합에의한수술은 19명이었다. 수술후평균 9.62개월 ( 범위 : 6-35개월 ) 까지경과관찰하였다. 수술후최종관찰시점에서평균원거리사시각은 6.83 ± 7.71PD, 근거리사시각은 3.02 ± 0.69PD였으며, 그결과근원거리사시각의차이는수술전 29.83 ± 19.25PD에서 3.44 ± 8.31PD로통계적으로유의하게감소하였다 (Table 3). 다시 DND-XT 군을내직근절제수술량의조정여부에 Table 3. Deviation angle preoperatively and at the last F/U Pre-op. (PD) Post-op. final F/U (PD) At distance fixation 46.55 ± 16.59 6.83 ± 7.71 At near fixation 14.93 ± 8.91 3.02 ± 0.69 Difference (D-N) 29.83 ± 19.25 3.44 ± 8.31 Values are presented as mean ± SD. F/U = follow-up; Pre-op. = preoperative; PD = prism diopters; Post-op. = postoperative; D-N = distant-near. Table 4. Deviation angle in patients with standard and reduced amount of medial resection Pre-op. (PD) Post-op. final F/U (PD) Group 1 (standard) At distance fixation 43.08 ± 9.47 10.09 ± 8.85 At near fixation 15.50 ± 9.03 5.06 ± 4.40 Difference (D-N) 27.83 ± 10.40 8.00 ± 11.45 Group 2 (reduced) At distance fixation 55.21 ± 18.87 4.20 ± 3.08 At near fixation 18.50 ± 6.25 2.02 ± 1.00 Difference (D-N) 28.68 ± 7.06 2.40 ± 2.08 Values are presented as mean ± SD. Pre-op. = preoperative; PD = prism diopters; Post-op. = postoperative; F/U = follow up; D-N = distant-near. 따라전통적술식수술군과내직근감량수술군으로구분하였을때전자는 16명, 후자는 17명으로나누어졌다. 전통적수술군 16명중 9명이최종관찰시점에서수술실패기준에해당하였다 ( 과교정 8명, 저교정 1명 ). 이에반해감량수술군 17명중수술실패기준에해당하는환자는단지 1명 ( 저교정 ) 으로전통적수술군에비해유의하게수술실패율이낮았다. 두군의수술전근원거리사시각의차이는각각 27.83 ± 10.40PD와 28.68 ± 7.06PD로유의한차이가없었으나, 수술후에는각각 8.00 ± 11.45PD와 2.40 ± 2.08PD 로감량수술군에서더유의하게감소하였다 (Table 4). 1601
- 대한안과학회지 2015 년제 56 권제 10 호 - 고찰 본연구에서근원거리사시각이차이나는감각외사시는전예에서눈벌림과다형 (divergence excess) 외사시였다. 즉원거리사시각이모두근거리사시각보다큰유형이었다. 이들은한눈시력저하에의해원거리융합눈모음능력이감퇴되어원거리외사시가되었으나근거리주시상태에서는상대적으로눈모음이유지되어원거리에서보다작은외사시각을유지하는형태이다. 저자들의조사결과, 강한근접눈모음에의해근거리외사시각을작게유지하는경우와고도조절눈모음비 (high accommodative convergence/accommodation ratio [AC/A]) 에의해작은근거리외사시각을유지하는경우가있었다. 23 고도조절눈모음비에의한눈벌림과다형감각외사시는근거리주시시의조절노력정도에따라근거리외사시각의크기가가변적이었고정위까지눈모음도가능한특성을보여주었다. 이에비해근접눈모음에의한눈벌림과다형감각외사시는주시여하에따라근거리외사시각이가변적이지않았고정위까지눈모음이가능한경우는없었다. 24 이들감각외사시환자는시력저하발생이전에는양안융합이가능한사람들이었기때문에한눈시력상실후원거리운동융합능력은잃어버렸으나근거리운동융합능력은약간저하되었거나유지하고있는상태라고할수있겠다. 본연구에서는전통적인 Parks formula에서의제안수술량보다내직근절제수술량을감량하여좋은수술결과를얻었다. Parks formula대로내직근절제술을하였을때, 수술후근거리에서과교정되는경우가많았다. 근거리과교정은시간경과후에도호전되지않았고재수술이필요하였다. 강한근접눈모음에의한눈벌림과다형감각외사시에서근접눈모음은불수의적눈모음이므로수술후원거리두눈정렬상태가정위가된후에도강한근접눈모음이작용할수있고이경우근거리과교정이쉽게일어날것이다. 또한고도조절눈모음비감각외사시유형에서도수술후고도조절눈모음비에의해근거리물체에대해조절노력을하는순간강한눈모음이유도될것이고이는근거리과교정으로나타날것으로유추할수있다. 따라서눈벌림과다형감각외사시에서는근거리주시시의과도한눈모음을줄여주어야수술후과교정발생을줄일수있을것이고이것은내직근절제수술량을감량함으로써가능할것이라고추론할수있겠다. 이러한추론에근거하여본연구에서는내직근절제수술량을감량하고상대적으로외직근후전수술량을증량하거나조정봉합수술방법에따라외직근후전수술량을조정하였다. 본연구의결과눈벌림과다형감각외사시에는내직근절제수술량을감량하는것이효과 적이라고판단된다. 후향적의무기록조사에의한연구방식이므로두수술법에의한효과를성급히단순비교하기에는무리가있을수있다. 이점은본연구의분명한제한점이다. 그러나저자들이임상경험에비추어전통적수술방식이근거리과교정을다수유발한다고판단하여특정시점부터는수술술기를바꾸어내직근절제수술량을감량하는방식으로수술하였기때문에, 본연구에서는후향적조사방식에따른약점은상대적으로작은편이라고생각된다. 결론적으로근원거리사시각이차이나는감각성외사시는눈벌림과다형외사시이고, 내직근절제수술량을감량하여수술하는방식이전통적인수술술식에비해수술성공률이높았다. 근접눈모음이나고도조절눈모음비에의해근거리눈모음이상대적으로강한유형의감각외사시이므로수술전눈모음의양상을분석하고근원거리사시각차이정도에따라내직근절제수술량을감량하고이에따라외직근후전수술량을조정하면전통적인기존술식에비해더높은수술성공률을얻을수있을것으로기대된다. 참고문헌 1) Havertape SA, Cruz OA, Chu FC. Sensory strabismus-eso or exo?. J Pediatr Ophthalmol Strabismus 2001;38:327-30; quiz 354-5. 2) Ciftci S, Simsek A, Dogan E, Ciftci L. Sensory exotropia due to keratoconus and review of the literature. Clin Ophthalmol 2013; 7:2069-72. 3) Lou DH, Xu YS, Li YM. Sensory exotropia subsequent to senile cataract. J Zhejiang Univ Sci B 2005;6:1220-2. 4) Fujikado T, Ohmi G, Ikeda T, et al. Exotropia secondary to vitreous hemorrhage. Graefes Arch Clin Exp Ophthalmol 1997;235:143-8. 5) Kim IG, Park JM, Lee SJ. Factors associated with the direction of ocular deviation in sensory horizontal strabismus and unilateral organic ocular problems. Korean J Ophthalmol 2012;26:199-202. 6) Gnanaraj L, Rao VJ. Corneal birth trauma: a cause for sensory exotropia. Eye (Lond) 2000;14 Pt 5:791-2. 7) Park BG, Kim JL, Lee SG. Clinical features associated with the direction of deviation in sensory strabismus. J Korean Ophthalmol Soc 2012;53:1138-42. 8) Kim KS, Park SC. The clinical consideration of sensory strabismus. J Korean Ophthalmol Soc 2005;46:316-22. 9) Choi MY, Hwang JM. Clinical analysis of sensory strabismus with organic amblyopia in children. J Korean Ophthalmol Soc 2005;46: 1374-81. 10) Brown SM. Fresnel prism treatment of sensory exotropia with restoration of sensory and motor fusion. J Cataract Refract Surg 1999;25:441-3. 11) Merino P, Mateos C, Gómez De Liaño P, et al. Horizontal sensory strabismus: characteristics and treatment results. Arch Soc Esp Oftalmol 2011;86:358-62. 12) Park YC, Chun BY, Kwon JY. Comparison of the stability of postoperative alignment in sensory exotropia: adjustable versus non- 1602
- 원훈재외 : 근원불일치감각외사시의수술결과 - adjustable surgery. Korean J Ophthalmol 2009;23:277-80. 13) Chang JH, Kim HD, Lee JB, Han SH. Supermaximal recession and resection in large-angle sensory exotropia. Korean J Ophthalmol 2011;25:139-41. 14) Hopker LM, Weakley DR. Surgical results after one-muscle recession for correction of horizontal sensory strabismus in children. J AAPOS 2013;17:174-6. 15) Gusek-Schneider G, Boss A. Results following eye muscle surgery for secondary sensory strabismus. Strabismus 2010;18:24-31. 16) Schulz E. Surgical indication and results in exotropia with divergence excess. Ophthalmologica 1983;187:1-7. 17) Kushner BJ. Selective surgery for intermittent exotropia based on distance/near differences. Arch Ophthalmol 1998;116:324-8. 18) Mohan K, Sharma A. A comparison of ocular alignment success of hang-back versus conventional bilateral lateral rectus muscle recession for true divergence excess intermittent exotropia. J AAPOS 2013;17:29-33. 19) Hertle RW, Granet DB, Schaffer MA, Wilson MC. Adjustable horizontal rectus recession surgery for disparate distance-near oscular deviations. Stabismus 1997;5:109-15. 20) Choi HY, Jung JH. Bilateral lateral rectus muscle recession with medial rectus pulley fixation for divergence excess intermittent extropia with high AC/A ratio. J AAPOS 2013;17:266-8. 21) Celebi S, Kükner AS. Large bilateral lateral rectus recession in large angle divergence excess exotropia. Eur J Ophthalmol 2001; 11:6-8. 22) Parks MM. Ocular Motility and Strabismus, 1st ed. Hagerstown: Harper & Row, 1975;113-22. 23) Nuzzi G, Mariani A, Barziza G, Andreozzi M. Proximal and accommodative convergence and age. Graefes Arch Clin Exp Ophthalmol 1982;218:110-2. 24) Bagolini B. Research on the behavior of proximal convergence in strabic and normal subjects (observations by means of determinations with the synotophore and with prisms). Boll Ocul 1961; 40:461-70. = 국문초록 = 근원거리사시각이차이나는감각외사시의수술결과 목적 : 근원거리사시각이차이나는감각외사시의수술결과를분석하고, 내직근절제감량여부에따라수술결과의차이를비교하고자하였다. 대상과방법 : 6 개월이상경과관찰한감각외사시환자들의의무기록을후향적으로조사하였다. 근, 원거리사시각차이가없는경우를기본감각외사시 (basic sensory exotropia, B-XT), 10 prism diopter (PD) 이상차이나는경우를불일치감각외사시 (distant-near disparity sensory exotropia, DND-XT) 라고이름하였다. 두군의임상자료를비교분석하였고, 내직근수술량의감량여부에따라전통술식군과감량절제군으로나누어수술결과및수술성공률을비교하였다. 수술성공기준은근, 원거리모두에서 10 PD 미만의편위를유지하고있는경우로정의하였다. 결과 : B-XT 군은 58 명, DND-XT 군은 33 명이었다. 두군간임상적특징의유의한차이는없었으나, 나쁜눈의시력은 DND-XT 군에서 B-XT 군보다유의하게좋았다. DND-XT 군의평균원거리외사시각은 46.55PD, 근거리외사시각은 14.93PD 로그차이는 29.83PD 였다. 이들은모두단안내직근절제및외직근후전술을받았고, 33 명수술환자중전통술식수술군은 16 명, 내직근감량수술군은 17 명이었다. 전통적수술군중 9 명이최종관찰시점에서수술실패기준에해당하였고, 감량수술군중수술실패환자는단지 1 명으로유의하게수술실패율이낮았다. 결론 : 전통적수술량에따라원거리사시각을수술하였을때과교정이많았으며내직근절제수술량을감량하였을때상대적으로더높은수술성공률을얻을수있었다. < 대한안과학회지 2015;56(10):1599-1603> 1603