대한안과학회지 2019 년제 60 권제 6 호 J Korean Ophthalmol Soc 2019;60(6):528-533 ISSN 0378-6471 (Print) ISSN 2092-9374 (Online) https://doi.org/10.3341/jkos.2019.60.6.528 Original Article 원시에서굴절교정레이저각막절제술과라식수술의비교 Comparison of Hyperopic Photorefractive Keratectomy and LASIK 김돈경 1 최재호 2 김성원 3 최태훈 1 최철명 1 Don Gyung Kim, MD 1, Jae Ho Choi, MD 2, Sung Won Kim, MS 3, Tae Hoon Choi, MD, PhD 1, Chul Myong Choe, MD, PhD 1 서울누네안과병원 1, 대구누네안과병원 2, 존스홉킨스대학교응용수학및통계학과 3 Nune Eye Hospital 1, Seoul, Korea Nune Eye Hospital 2, Daegu, Korea Department of Mathematics and Statistics, Johns Hopkins University 3, Baltimore, MD, USA Purpose: We compared the results of photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK) for the correction of hyperopia. Methods: Patients who underwent PRK or LASIK, under +6.00 diopters (D) hyperopia and under 2.00 D astigmatism were included. In total, 21 patients (38 eyes) underwent PRK surgery and 25 patients (41 eyes) underwent LASIK surgery. We compared the visual acuity, refractive error, safety, and efficacy between the two groups. Results: The manifest refractive spherical equivalent (MRSE) of the PRK and LASIK groups at 1 and 3 months after surgery was significantly different between the two groups (p < 0.05). However, the MRSE was not significantly different at postoperative 6 and 12 months between the two groups. The uncorrected visual acuity (UCVA) of the PRK and LASIK groups at 1 month after surgery was significantly different between the two groups (p < 0.05). However, the UCVA was not significantly different at postoperative 3, 6, and 12 months between the two groups. The best corrected visual acuity was not significantly different at postoperative 1, 3, 6, and 12 months between the two groups. The safety index was not significantly different between the two groups at postoperative 1, 3, 6, and 12 months. The efficacy index of the PRK group was lower than that of the LASIK group at 1 month after surgery. However, the efficacy index was not significantly different at postoperative 3, 6, and 12 months between the two groups. There was no statistically significant difference between the predictability of the two groups at postoperative 1 year. Conclusions: After PRK treatment, temporary myopic deviation was observed after 1 month, but there was no significant difference between the two treatments after 3 months of follow up. In the correction of hyperopia, there was no significant difference between PRK and LASIK in efficacy or safety. J Korean Ophthalmol Soc 2019;60(6):528-533 Keywords: Hyperopia, LASIK, Photorefractive keratectomy Received: 2018. 5. 3. Revised: 2018. 9. 11. Accepted: 2019. 5. 17. Address reprint requests to Chul Myong Choe, MD, PhD Nune Eye Hospital, #404 Seolleung-ro, Gangnam-gu, Seoul 06198, Korea Tel: 82-2-2086-7750, Fax: 82-2-2086-7710 E-mail: cmchoe@gmail.com * Conflicts of Interest: The authors have no conflicts to disclose. 현재근시교정의수술적치료로굴절교정레이저각막절제술 (photorefractive keratectomy, PRK) 과레이저각막절삭가공성형술 (laser in situ keratomileusis, LASIK) 이임상에서사용되고있으며, 유용성을인정받고있다. 1-5 원시교정에있어서도레이저굴절교정수술을시도하였으나, 각막주변부절삭으로인한구조적인불안정성, 잠복원시, 제한된광학부의크기, 흔한원시퇴행등여러제약이있었다. 6-8 c2019 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. 528
- 김돈경외 : 원시에서 PRK 와라식수술의비교 - 이로인해원시에서의굴절교정수술은근시에서의굴절교정수술에비해낮은효용성과안정성, 여러합병증을동반한제한된성공만이보고되고있다. 9,10 하지만최근에는굴절교정수술의비약적인발전으로새로운기술을이용한원시의교정시도가보고되고있다. 눈의움직임에도정확하게레이저빔을조사할수있는 6세대 Amaris excimer laser 기술을이용한원시환자의라식굴절교정수술연구가발표되었으며 11 기존의 Excimer laser system (193 nm wavelength) 이아닌 Solid-state laser system (213 nm wavelength) 을이용한원시환자의 PRK 수술결과도보고되었다. 12 이처럼국외에서는굴절교정수술의발달로원시에서 PRK 수술과라식수술의개선된결과가보고되고있지만, 국내에서는원시환자에서라섹수술후원시교정및내사시교정에효과적임을보여준연구 1예만있다. 13 본연구에서는원시교정에서의 PRK 수술과라식수술의임상성적및효율성과안정성을비교분석하고자한다. 대상과방법 2009년 9월부터 2014년 9월까지본원에서 PRK 수술이나라식수술을받고 1년이상추적관찰이가능했던 +6.00 D 이내원시, 난시 -2.00 D 이내환자들중에서 PRK 수술을시행받은 21명 (38안) 과라식수술을시행받은 25명 (41안) 을대상으로의무기록을후향적으로분석하였다. 각막수술력이있거나, 각막에병변이있는경우, 켈로이드체질, 녹내장병력, 망막에병변이있는경우는연구에서제외하였다. 모든환자들에서수술전나안시력과최대교정시력을측정하였으며, 현성굴절검사, 조절마비굴절검사, 안압측정, 세극등검사및안저검사, 동공크기측정, 중심각막두께측정, 각막지형도검사를시행하였다. 현성굴절검사와조절마비굴절검사결과의차이가있는경우는조절마비굴절검사값을기준으로레이저절삭 (ablation) 을시행하였다. PRK 군과라식군모두정시 (emmetropia) 를최종목표굴절력으로정하였다. 본연구에서시행된 PRK 수술과라식수술은모두 SCHWIND Amaris 500 Hz excimer laser (SCHWIND eye-tech-solutions Kleinostheim, Germany) 를이용하여, 동공축 (pupil center) 을기준으로각막레이저절삭을시행하였다. PRK 수술은 0.5% proparacaine 점안액 (Alcaine, Alcon Laboratories, Fort Worth, TX, USA) 으로점안마취한후, 8.5 mm 직경의알코올용액용기를각막위에놓고증류수로희석시킨 20% 알코올을용기안에가득채우고기다린후평형염액 (balanced salt solution [BSS], Alcon Laboratories) 으로충분히세척하였다. 이후상피미세괭이 (epithelial microhoe) 를이용하여각막상피를주변부부터부드럽게벗겨내고제거하였다. 이후 Amaris 500 Hz eximer laser를이용하여레이저절삭을시행한후치료용콘택트렌즈를착용하게하였다. 술후 0.5% Levofloxacine 점안액을하루 4번씩 1주일점안하도록하였다. 0.1% Fluorometholone을하루 4번씩 3개월간점안하도록하였고다음 2개월간은점안횟수를줄여나갔다. 라식수술은 0.5% proparacaine 점안액으로점안마취한후개검기를사용하여각막을노출시켰다. 또한평형염액 (BSS) 으로각막, 결막을세척한후, Merocel sponge를이용하여수분을흡수하였다. 흡입고리 (9.5 mm) 로안구를고정한후, 안압을 60 mmhg 이상되도록음압을걸고, SBK microkeratome (MORIA, Antony, France) 미세각막절삭기로비측기저의두께가 100 μm인각막절편을만들었다. 각막절편을젖힌후 Amaris 500 Hz eximer laser를이용하여레이저절삭을시행한후평형염액으로세척하고각막절편을원위치시킨후, merocel sponge를이용하여건조시켰다. 술후 0.5% Levofloxacine 점안액과 0.1% Fluorometholone 을하루 4번씩 2주간점안하도록하였고이후 2주간점안횟수를줄여나갔다. 술후 1개월, 3개월, 6개월, 1년에각각추적관찰하여나안시력, 세극등검사, 안압측정, 현성굴절검사를시행하였다. 그외안정성 (safety index) 은 술후최대교정시력 / 술전최대교정시력 이라고정의하여측정하였으며, 효율성 (efficacy index) 을 술후나안시력 / 술전최대교정시력 이라고정의하여측정하였다. 예측성 (predictability index) 은 술후구면렌즈대응치가목표굴절값인정시에서 ± 0.50 D 이내인비율 이라고정의하여측정하였다. PRK군과라식군의술후임상성적의비교는독립표본 t- 검정 (independent two-sample t-test) 을이용하여분석하였으며, 예측성 (predictability) 비교는 Fisher s exact test를이용하여분석하였다. 모든통계분석은 SPSS 프로그램 (IBM SPSS ver. 21.0, IBM Corp., Armonk, NY, USA) 을이용하였다. 모든경우에서 p값이 0.05 미만인경우통계적으로의미가있는것으로해석하였다. 본연구는본원의인증된연구윤리심의위원회 (IRB) 의승인을받았으며 ( 승인번호 : N-1804-001-999), 헬싱키선언을준수하였다. 결과 PRK 수술을시행받은 21명 (38안) 과라식수술을시행받은 25명 (41안) 의남녀의비는각각 9:12명, 6:19명이며술전평균연령은 32.9 ± 9.9세, 38.7 ± 13.2세로통계적으로 529
- 대한안과학회지 2019 년제 60 권제 6 호 - 유의한차이는없었다 (p>0.05). 술전평균구면렌즈대응치는 PRK군에서 2.90 ± 1.46 D, 라식군에서 2.61 ± 1.12 D 로두군간에통계적으로유의한차이는없었으며 (p>0.05), 술전나안시력및최대교정시력도두군간에통계적으로유의한차이는없었다 (p>0.05) (Table 1). 두군의광학부의크기 (optical zone) 는통계적으로유의한차이는없었다 (p>0.05) (Table 1). 그러나두군의레이저절삭면의넓이 (ablation zone) 및절삭부의깊이 (depth) 는통계적으로유의한차이가있었다 (p<0.05) (Table 1). 평균구면렌즈대응치는술후 1개월째 PRK군에서 -0.43 ± 0.91 D, 라식군에서 0.34 ± 0.51 D로 PRK군에서근시양상을보여두군간에통계적으로유의한차이가있었다 (p<0.05). 술후 3개월째평균구면렌즈대응치는 PRK군에서 0.04 ± 0.65 D, 라식군에서 0.64 ± 0.53 D로, PRK군에서근시양상은회복되었으나여전히두군간에통계적으로유의한차이는있었다 (p<0.05). 술후 6개월그리고 1년에평균구면렌즈대응치를비교하면, 두군간에통계적으로유의한차이는없었다 (p>0.05) (Fig. 1). 나안시력은술후 1개월째에 PRK군에서 0.25 ± 0.21 logmar, 라식군에서 0.14 ± 0.23 logmar로통계적으로유의한차이가있었다 (p<0.05). 술후 3개월, 6개월, 그리고 1년에나안시력을비교하면두군간에통계적으로유의한 차이는없었다 (p>0.05) (Table 2). 술후 1 년에 PRK 군에서 39.4% 가나안시력이 1.0 이상달성되었고, 63.1% 가 0.8 이상달성되었다. 라식군에서는 34.1% 가나안시력이 1.0 이상달성되었고, 65.8% 가 0.8 이상달성되었다. 두군간에통계적으로유의한차이는없었다 (p>0.05) (Fig. 2). 최대교정시력은술후 1개월, 3개월, 6개월, 그리고 1년에서모두두군간에통계적으로유의한차이는없었다 (p>0.05) (Table 3). 안정성 (safety index) 은 PRK군과라식군모두수술후 Figure 1. Changes in spherical equivalent manifest refraction over time after hyperopic PRK and LASIK. PRK = photorefractive keratectomy; LASIK = laser in situ keratomileusis; D = diopter; Pre op = preoperation. Table 1. Demographics of the surgical patients Variable PRK LASIK p-value * Patients (eyes) 21 (38) 25 (41) Sex (M/F) 9/12 6/19 0.182 Age (years) 32.9 ± 9.9 (22-58) 38.7 ± 13.2 (23-60) 0.268 UCVA (logmar) 0.39 ± 0.28 0.43 ± 0.40 0.581 BCVA (logmar) 0.11 ± 0.16 0.10 ± 0.22 0.908 Preoperative SE (D) 2.90 ± 1.46 (1-5.25) 2.61 ± 1.12 (1-4.75) 0.328 Optical zone (μm) 6.83 ± 0.47 6.42 ± 0.27 0.058 Ablation zone (μm) 8.70 ± 0.35 7.87 ± 0.33 0.000 Ablation depth (μm) 76.09 ± 27.10 55.66 ± 26.30 0.000 Values are presented as mean ± standard deviation (range) unless otherwise indicated. PRK = photorefractive keratectomy; LASIK = laser in situ keratomileusis; M/F = male/female; UCVA = uncorrected visual acuity; logmar = the logarithm of minimal angle of resolution; BCVA = best corrected visual acuity; SE = spherical equivalent; D = diopter. Table 2. Changes in UCVA over time after PRK and LASIK Pre-OP 1 month 3 months 6 months 1 year PRK (logmar) 0.39 ± 0.28 0.25 ± 0.21 0.12 ± 0.15 0.11 ± 0.14 0.11 ± 0.13 LASIK (logmar) 0.43 ± 0.40 0.14 ± 0.23 0.15 ± 0.26 0.17 ± 0.25 0.16 ± 0.27 p-value * 0.581 0.028 0.611 0.343 0.266 Values are presented as mean ± standard deviation unless otherwise indicated. UCVA = uncorrected visual acuity; PRK = photorefractive keratectomy; LASIK = laser in situ keratomileusis; Pre op = preoperation; logmar = the logarithm of minimal angle of resolution. 530
- 김돈경외 : 원시에서 PRK 와라식수술의비교 - 1개월이후부터 0.80 이상으로유지되었으며술후 1년째에안정성은 PRK군은 1.16 ± 0.52, 라식은 1.01 ± 0.18이었다. 술후 1개월, 3개월, 6개월, 그리고 1년에두군간의안정성은통계적으로유의한차이는관찰되지않았다 (p>0.05) (Table 4). 효율성 (efficacy index) 은술후 1개월째에 PRK군의효율성이 0.77 ± 0.33, 라식군의효율성이 0.93 ± 0.16으로 PRK 군의효율성이라식군보다통계적으로유의한차이를보이며낮았으나 (p<0.05), 술후 3개월, 6개월, 그리고 1년에는두군간의효율성은통계적으로유의한차이를보이지않 았다. 술후 1년째효율성은 PRK군 1.02 ± 0.25, 라식은 0.94 ± 0.18이었다 (Table 4). 술후 1년째 ± 0.5 D 이내의예측성 (predictability) 은 PRK군에서 52.6%, 라식군에서 36.5% 를보였고 ± 1.0 D 이내의예측성은 PRK군에서 78.9%, 라식군에서 68.2% 를보였다. 두군의 ± 0.5 D 이내의예측성과 ± 1.0 D 이내의예측성을 Fisher s exact test를이용하여분석한결과통계적으로유의한차이를보이지않았다 (p>0.05) (Fig. 3). Figure 2. Uncorrected visual acuity at postoperative 1 year follow up. PRK = photorefractive keratectomy; LASIK = laser in situ keratomileusis. Figure 3. PRK and LASIK predictability. The percentage of eyes within ± 0.5 D and ± 1.0 D. PRK = photorefractive keratectomy; LASIK = laser in situ keratomileusis; D = diopter; SE = spherical equivalent. Table 3. Changes in BCVA over time after PRK and LASIK Pre-OP 1 month 3 months 6 months 1 year PRK (logmar) 0.11 ± 0.16 0.12 ± 0.14 0.10 ± 0.16 0.08 ± 0.12 0.06 ± 0.08 LASIK (logmar) 0.10 ± 0.22 0.09 ± 0.22 0.12 ± 0.27 0.13 ± 0.26 0.10 ± 0.23 p-value * 0.908 0.580 0.733 0.380 0.292 Values are presented as mean ± standard deviation unless otherwise indicated. BCVA = best corrected visual acuity; PRK = photorefractive keratectomy; LASIK = laser in situ keratomileusis; Pre op = preoperation; logmar = the logarithm of minimal angle of resolution. Table 4. Comparison in the safety index and efficacy index of PRK & LASIK groups POD 1 month 3 months 6 months 1 year Safety index PRK 1.05 ± 0.55 0.98 ± 0.65 0.97 ± 0.70 1.16 ± 0.52 LASIK 0.84 ± 0.41 0.87 ± 0.36 0.86 ± 0.43 1.01 ± 0.18 p-value * 0.057 0.349 0.390 0.092 Efficacy index PRK 0.77 ± 0.33 0.93 ± 0.36 0.94 ± 0.37 1.02 ± 0.25 LASIK 0.93 ± 0.16 0.88 ± 0.26 0.85 ± 0.37 0.94 ± 0.18 p-value * 0.007 0.443 0.328 0.105 Values are presented as mean ± standard deviation unless otherwise indicated. PRK = photorefractive keratectomy; LASIK = laser in situ keratomileusis; POD = post operation day. 531
- 대한안과학회지 2019 년제 60 권제 6 호 - 술후 1년의경과관찰에서 PRK군과라식군모두에서시력에영향을미칠만큼의각막혼탁은발생하지않았다. 라식군에서는각막절편과관련된합병증인각막주름 (striae), 단추모양각막절편 (button holes), 상피내생 (epithelial ingrowth), 미만층판각막염 (diffuse lamellar keratitis) 은관찰되지않았다. 고찰 PRK 수술과라식수술은우리나라에서주로근시의치료에적용되었고원시치료에적용된경우는그에비해드물다. 이번연구의목적은원시교정에있어서 PRK 수술과라식수술의임상성적및안전성과효율성을비교분석하는것이다. 술후 1개월째 PRK군의평균구면렌즈대응치는 -0.43 ± 0.91 D로근시양상을보였다. 과거 Danjoux et al 14 와 Ibrahim 15 이시행한연구에서도원시환자에서 PRK 수술을시행한경우술후 1개월째근시양상을보였으며, 근시양상이발생하는원인은각막상피재생시간이연장되었기때문이라고주장하였다. 각막상피재생시간은각막절삭의형태 (ablation profile) 와각막절삭면의넓이 (ablation zone size) 에영향을받는데, 특히근시교정보다원시교정에서더깊은각막절삭이필요하며, 이런요인이각막상피재생시간을연장시킨다고주장하였다. Serrao and Lombardo 16 가시행한연구에서는경도, 중등도원시환자와고도원시환자에서각막상피재생시간을비교했고, 중심각막굴절력이더높은고도원시에서각막상피재생이지연된다고보고하였다. 술후 1개월째평균구면렌즈대응치는 PRK군이 -0.43 ± 0.91, 라식군이 0.34 ± 0.51이고, 술후 1년째평균구면렌즈대응치는 PRK군이 0.47 ± 0.91, 라식군이 0.34 ± 0.51로술후원시로의이행폭은 PRK군이라식군보다더크다. 이러한현상도 PRK 수술의특성상각막상피재생시간이긴것과연관이있다고판단된다. 이번연구의 1년째측정한안정성 (safety index) 은 PRK 군이평균 1.16 ± 0.52, 라식군이평균 1.01 ± 0.18이었으며, 효율성 (efficacy index) 은 PRK군이평균 1.02 ± 0.25, 라식군이 0.94 ± 0.18이었고, ± 0.5 D 이내의예측성 (predictability index) 은 PRK군이 52.6% 라식군이 36.5% 였다. 모든결과에있어서두군사이의통계적으로유의한차이는없었다. 이는이전 Frings et al 17 이시행한원시환자에서의 PRK 수술과라식수술의차이를비교한연구와같은결과로상기연구에서도두군사이의안정성, 효율성에차이가없는것으로나타났다. 본연구의한계점은원시교정을필요로하는환자가많지않아개체수가적었던것, 추적관찰의기간이 1년으로짧았던점이다. 향후대규모의전향적인연구를통해, 원시교정에있어서 PRK 수술과라식수술의안정성과효율성, 예측성을비교하고분석해야할것으로보인다. 또한근시환자들과의비교를통해근시와원시에있어서각수술별차이를안정성, 효율성, 예측성측면으로비교한다면유의미한결과를도출할수있을것으로판단된다. 결론적으로원시교정에서 PRK 수술과라식수술은안정성, 효율성, 예측성측면에서차이가없는수술방법이라판단된다. REFERENCES 1) El-Maghraby A, Salah T, Waring GO 3rd, et al. Randomized bilateral comparison of excimer laser in situ keratomileusis and photorefractive keratectomy for 2.50 to 8.00 diopters of myopia. Ophthalmology 1999;106:447-57. 2) He L, Manche EE. Contralateral eye-to-eye comparison of wavefront-guided and wavefront-optimized photorefractive keratectomy: a randomized clinical trial. JAMA Ophthalmol 2015;133: 51-9. 3) Shortt AJ, Allan BD, Evans JR. Laser-assisted in-situ keratomileusis (LASIK) versus photorefractive keratectomy (PRK) for myopia. Cochrane Database Syst Rev 2013;1:CD005135. 4) Hersh PS, Brint SF, Maloney RK, et al. Photorefractive keratectomy versus laser in situ keratomileusis for moderate to high myopia. A randomized prospective study. Ophthalmology 1998; 105:1512-22, discussion 1522-3. 5) Han HS, Song JS, Kim HM. Long-term results of laser in situ keratomileusis for high myopia. Korean J Ophthalmol 2000;14:1-6. 6) de Ortueta D, Arba Mosquera S. Topographic stability after hyperopic LASIK. J Refract Surg 2010;26:547-54. 7) McGhee CN, Ormonde S, Kohnen T, et al. The surgical correction of moderate hypermetropia: the management controversy. Br J Ophthalmol 2002;86:815-22. 8) Azar DT, Primack JD. Theoretical analysis of ablation depths and profiles in laser in situ keratomileusis for compound hyperopic and mixed astigmatism. J Cataract Refract Surg 2000;26:1123-36. 9) Primack JD, Azar DT. Refractive surgery for hyperopia. Int Ophthalmol Clin 2000;40:151-63. 10) Sher NA. Hyperopic refractive surgery. Curr opin Ophthalmol 2001;12:304-8. 11) Plaza-Puche AB, Yebana P, Arba-Mosquera S, Alió JL. Three-year Follow-up of Hyperopic LASIK using a 500-Hz Eximer Laser System. J Refract surg 2015;31:674-82. 12) Shah S, Sheppard AL, Castle J, et al. Refractive outcomes of laser-assisted subepithelial keratectomy for myopia, hyperopia, and astigmatism using a 213 nm wavelength solid-state laser. J Cataract Refract Surg 2012;38:746-51. 13) Choi SH, Kim SJ, Kim MK, Wee WR. Short-term clinical results of hyperopic LASEK in Korean patients. J Korean Ophthalmol soc 2015;56:1527-33. 14) Danjoux JP, Kalski RS, Cohen P, et al. Excimer laser photorefractive keratectomy for hyperopia. J Refract Surg 1997;13:349-55. 532
- 김돈경외 : 원시에서 PRK 와라식수술의비교 - 15) Ibrahim O. Laser in situ keratomileusis for hyperopia and hyperopic astigmatism. J Refract Surg 1998;14(2 Suppl):S179-82. 16) Serrao S, Lombardo M. Corneal epithelial healing after photorefractive keratectomy: analytical study. J Cataract Refract Surg 2005;31:930-7. 17) Frings A, Richard G, Steinberg J, et al. LASIK and PRK in hyperopic astigmatic eyes: is early retreatment advisable? Clin Ophthalmol 2016;10:565-70. = 국문초록 = 원시에서굴절교정레이저각막절제술과라식수술의비교 목적 : 원시에서굴절교정레이저각막절제술 (photorefractive keratectomy, PRK) 과라식수술을비교분석하였다. 대상과방법 : +6.00 D 이내원시, 난시 2.00 D 이내인환자들중, PRK 수술을시행받은 38 안 (21 명 ) 과라식수술을시행받은 41 안 (25 명 ) 을대상으로술후시력, 굴절력, 안정성, 효율성및예측성을비교분석하였다. 결과 : 평균구면렌즈대응치는술후 1 개월, 3 개월에 PRK 군과라식군사이에통계적으로유의한차이가있었으나 (p<0.05), 술후 6, 12 개월에는유의한차이는없었다 (p>0.05). 나안시력은술후 1 개월째 PRK 군과라식군사이에통계적으로유의한차이가있었으나 (p<0.05), 술후 3, 6, 12 개월에는유의한차이는없었다 (p>0.05). 최대교정시력은술후 1, 3, 6, 12 개월에두군에서통계적으로유의한차이는없었다. 안정성은술후 1, 3, 6, 12 개월에두군에서통계적으로유의한차이는없었다 (p>0.05). 효율성은술후 1 개월째 PRK 군이라식군보다통계적으로유의하게낮았으나 (p<0.05), 술후 3, 6, 12 개월에통계적으로유의한차이는없었다 (p>0.05). 술후 1 년째예측성은두군사이에통계적으로유의한차이는없었다 (p>0.05). 결론 : PRK 수술에서술후 1 개월째라식수술에비해근시양상을보였으나, 술후 3 개월이후에는두수술간의차이가없었다. 원시환자에서 PRK 수술과라식수술의효율성과안정성은술후 3 개월이후차이가없는것으로판단된다. < 대한안과학회지 2019;60(6):528-533> 김돈경 / Don Gyung Kim 서울누네안과병원 Nune Eye Hospital 533