ISSN(print) 1226-5012 21(2):91-98, June 2016 < 초청논문 > http://dx.doi.org/10.14479/jkoos.2016.21.2.91 Study of Masking Effect of Soft Contact Lenses on Cornea after Refractive Surgery Ye-Rim Moon, Hyung-Min Park, and Byoung-Sun Chu* Dept. of Optometry and Vision Science, Catholic University of Daegu, Institute for Eye-functional Promotion, Gyeongsan 38430, Korea (Received November 11, 2015: Revised March 15, 2016: Accepted May 9, 2016) Purpose: This study investigated the masking effect of the hydrogel lens and silicone hydrogel lens on the cornea with refractive surgery and without surgery. Methods: 24 university students (means age: 23.48±2.89 years) without refractive surgery (12, control group) and with refractive surgery (LASIK: 8, LASEK: 4, experimental group) participated in the study. Mean refractive errors of right eyes were 2.73 D for control group and 0.24 D for experimental group. The differences in the refractive power and corneal topography map between pre- and post-wearing the 3.00 D lenses were compared, and 2 kinds of hydrogel contact lenses (0.89 Mpa, 0.49 Mpa) and 2 kinds of silicone hydrogel lenses (1.5 Mpa, 0.8 Mpa) were used for 3.00 D lenses. NVision-K5001 (Shin nippon, Japan) was used to measure the refractive power and Keratograph 5M (Oculus, Germany) to measure the corneal topography map change. Results: Variations in the refractive power increased to the plus direction in the experimental group after wearing soft contact lenses. The corneal topography map showed significant changes on the both groups after wearing soft contact lenses (p<0.05). However there were no significant differences in the refractive power and corneal topography map variations by lens materials. Conclusions: Wearing soft contact lenses showed corneal topography map changes. Especially wearing soft contact lenses on the flat cornea after corneal refractive surgery showed greater corneal power changes. Therefore, it should pay attention to refractive change in case of prescribing soft contact lenses to patients with corneal refractive surgery. Key worlds: Silicone hydrogel contact lens, Modulus, Corneal refractive surgery, Irregular astigmatism, Corneal topography 서론현대사회에서보급화된스마트기기사용증가및근거리작업시간의과도한증가와같은환경적인요인 [1] 에의하여우리나라근시발생률이증가하고있다. 근시는조절휴지상태에서전방무한대의물체에서나온광선이눈으로들어가망막앞에초점을맺는것으로 [2] 2008년도국민건강영양조사중안검사결과 [3] 에따르면각연령층비정시군중에서근시가차지하는비율이 5세이상 53%, 12-18세 84.1%, 19-29세 74.1%, 30-39세 65.4% 로각연령층에서보여지는것과같이근시가비정시중에가장많은범위를차지하고있다. 이러한비정시를교정하기위한방법으로안경, 콘택트렌즈, 각막굴절교정수술, Orthokeratology렌즈가주로사용되어지고있는데그중안경과콘택트렌즈착용률이 1987년도부터 2013년도까지지난 20년동안안경약 2배, 콘택트렌즈약 4배가증가하였다. 렌즈사용자의재질에따른사용추이를살펴보면실리콘하이드로겔 64%, 하이드로겔 24%, Gas permeable 9%, Hybrid 2%, 그리고 PMMA 1% 순으로나타난다. [4] 이중에서기존의하이드로겔성분에실리콘을함유시킨실리콘하이드로겔렌즈의사용률이가장큰범위를차지하고있다. 2010년도부터 2013년도까지전세계적인실리콘하이드로겔렌즈사용현황은큰폭의증가추세를보이지않았지만국내의실리콘하이드로겔렌즈의사용현황은 2010 년 17% 정도의사용률에서 2013년 24% 까지해를거듭할수록많은사람들이실리콘하이드로겔렌즈를사용하고있다. 실리콘하이드로겔렌즈는높은산소투과성과높은함수율로많은사람들에게사용되어지고있다. 하지만실리 *Corresponding author: Byoung-Sun Chu, TEL: +82-53-850-2553, E-mail: bschu@cu.ac.kr 91
92 Ye-Rim Moon, Hyung-Min Park, and Byoung-Sun Chu 콘하이드로겔렌즈는실리콘성분의특성으로인해모듈러스가높아지게된다. 모듈러스는변형을생성하는데필요한단위면적당힘또는 stress to stain 으로, [5] 콘택트렌즈재료의특성을평가하는중요한요소로실리콘성분의함유로모듈러스가높아진실리콘하이드로겔렌즈의경우기존하이드로겔렌즈에비해모양유지와핸들링이좋지만눈이뻑뻑한느낌이강해첫착용감에있어서불편을야기할수있는단점이있다. [6] 이러한실리콘하이드로겔렌즈의경우이론적으로편평하고불규칙한각막에착용시, 편평한각막에비해상대적으로곡률이급한렌즈의베이스커브로인하여렌즈와각막사이의공간에 + 누액효과가발생되어굴절력에영향을미치게된다. 이러한굴절영향은 1983년 Trokel [7] 등이각막에엑시머레이저를이용한수술후, 불규칙한난시 [8] 가발생한각막형태를갖고있는각막굴절교정수술자들에게흔히발생한다. 현재우리나라에서는각막굴절교정수술이라는근시교정수술을매년약 10만명의사람들이받고있으며, 최근몇년동안각막굴절교정수술을받는사람들이급격하게증가하였고앞으로해를거듭할수록굴절수술안은더증가할것이다. [9] 각막굴절교정수술은안경이나콘택트렌즈와같은시력보조기구를착용하지않아도된다는가장큰장점을갖고있는수술이지만수술자들중상당수가부작용을호소하고있다. 한연구에따르면각막굴절교정수술은건성안, [10] 각막절편주름, 각막중심이탈, 각막혼탁, 불규칙난시, 근시퇴행, 야간눈부심, 야간운전어려움, 달무리증상, 허상, 기울어져보임, 대비감도시력감소, 최대교정시력감소, 단안복시, 이물감, 통증, 흐리게보임등다양한합병증들이보고되고있다. [11] 각막굴절교정수술자의가장주된불편함은눈이시리고뻑뻑하게느껴지는현상과불빛이번져보이는야간빛번짐현상이다. [12] 그중야간빛번짐현상은불규칙한난시로인한현상중의하나이며, 불규칙한난시는각막굴절교정수술후가장흔하게발생하는현상이며 [13] 이러한부작용으로인해각막굴절교정수술자들은안경또는콘택트렌즈재착용을필요로하게된다. [14] 시력보조기구중안경은그들의균일하지않은각막에의해나타난불규칙난시를보정할수있는적절한방법이될수없다. [15] 반면모듈러스가높은 Rigid lens는각막과렌즈사이의공간에나타난 Masking 효과로인하여각막에발생한불규칙한난시를보정하는가장대표적인방법으로최근까지가장일반적인불규칙한난시보정방법으로알려져있다. [15,16] 또한 Rigid lens에비해모듈러스가낮은소프트콘택트 렌즈또한불규칙한각막난시를보정하는 Masking 효과가나타난다는연구가있으며, [15] 실리콘성분으로인하여기존하이드로겔렌즈보다모듈러스가높아진실리콘하이드로겔렌즈의디자인및충분한두께가 Masking 효과를나타내는역할을한다는연구결과가있다. [15,17] 따라서소프트콘택트렌즈는안경에비해불규칙한각막을보정하는더좋은역할의시력보조기구로써의역할을한다. [18] 이뿐만아니라소프트콘택트렌즈의편안한착용감으로인하여 Rigid lens보다착용자들의높은만족도를얻고있다고한다. 이와반대로또다른연구에서는소프트콘택트렌즈는편안한착용감을주지만각막굴절교정수술자들에게착용시소프트렌즈의모양을잃어버려 Rigid lens와같은수차제거효과는나타나지않는다는의견도제시되어있다. [15] 현재국내에는각막굴절교정수술자의급증과함께나타나는불규칙한난시발생으로인한부작용을호소하는수술자들을위한적절한관리에관한연구가미흡한상황이다. 따라서본연구는일반하이드로겔렌즈와실리콘하이드로겔렌즈의서로다른모듈러스의렌즈를착용하였을때나타나는 Masking 효과여부와정상인의각막과각막굴절교정수술로인하여불규칙해진각막표면에콘택트렌즈를착용시켰을때나타나는서로다른 Masking 효과에관한연구를통하여서로다른재질및정상인각막 (control group: 통제군 ) 과각막굴절교정수술자의각막 (experimental: 실험군 ) 에나타나는 Masking 효과를알아보고자한다. 대상및방법 1. 연구대상본연구의대상자는각막굴절교정수술이외에각막이나안구에영향을미치는기타안질환및어떠한전신질환이없는대구가톨릭대학교학생중각막굴절교정수술자 12명의우안과비수술자 12명의우안을대상으로선정하였다. 각막굴절교정수술후경과기간이 6개월미만인자는연구에서제외하였고, 연구에참여자들은연구의목적과검사내용숙지후검사에참여하였다. 2. 연구방법 1) 연구에사용한소프트콘택트렌즈실험에사용한렌즈는하이드로겔렌즈 2종, 실리콘하이드로겔렌즈 2종으로재질, 함수율, 직경, 베이스커브, 산소투과성, 모듈러스의특성이모두다른 Table 1의소프트콘택트렌즈 4가지를무작위로참여자의우안에착용하
Study of Masking Effect of Soft Contact Lenses on Cornea after Refractive Surgery 93 Table 1. Specification of contact lenses used in this study Type 도록지시하였다. H1 H2 S1 S2 Hydrogel Hydrogel Silicone- Hydrogel Silicone- Hydrogel Power (D) 3.00 3.00 3.00 3.00 Water content (%) 69 60 24 48 Diameter (mm) 14.0 14.2 13.8 14.0 B.C (mm) 8.7 8.7 8.6 8.6 Dk/t at 3.00 26 28 175 160 Modulus (Mpa) 0.89 0.49 1.5 0.8 2) 소프트콘택트렌즈착용시그룹간굴절력교정효과굴절력측정은 SHIN NIPPON의 NVision-K 5001을이용하여조절마비제를사용하지않은상태로양안개방후측정하였다. 측정은어떠한장애물이없는공간의 6 m 떨어진원거리시표주시후나안및각렌즈착용후에각 3회씩측정하였고, 측정되어진굴절력값은등가구면굴절력 (SE) 값을사용하여굴절력의변화를비교하였다. 3) 소프트콘택트렌즈착용시그룹간각막지형도의변화각막지형도측정은 OCULUS의 Keratograph 5M을사용하여나안및각렌즈착용후피검사자의눈물층이안정된상태를마이어상의균일성을통하여확인후항목별각 2회씩촬영하였다. 측정된항목은 Fig. 1에서보여지는각막지형도를통하여비측 (nasal), 이측 (temporal), 하측 (inferior), 상측 (superior) 의 Center, 2 mm영역, 4 mm영역, 6 mm영역, 8 mm영역을이용하여각막지형도의변화를비교하였다. 착용시각막곡률반경에따른 Masking 효과와서로다른재질의렌즈착용시나타나는 Masking 효과를알아보고자하였다. 연구를통하여얻어진데이터는 ANOVA 통계를이용하여비교하였고통계분석에서 p<0.05 일때통계적으로유의한차이가있는것으로판단하였다. 결과및고찰 1. 굴절력변화량 1) 렌즈착용후, 수술자와비수술자의굴절력변화량비교소프트콘택트렌즈착용후수술자와비수술자의굴절력변화를비교한결과 (Fig. 2), 수술자는소프트콘택트렌즈착용후 0.64 D만큼의굴절력변화가나타났으며, 비수술자의경우 0.41 D만큼의굴절력변화가나타났다. 두그룹간의차이는 0.23 D였으며, 수술자그룹에서 + 방향으로굴절력증가하였고, 통계적으로유의한차이를보였다 (p=0.006). 2) 비수술자의렌즈재질에따른굴절력변화량비교비수술자의렌즈착용전과각재질별렌즈착용후굴절력의변화는 Fig. 3에서보여지는것과같이 H1 3. 통계처리본연구에서는위의측정값을통하여소프트콘택트렌즈 Fig. 2. Comparison of refractive power variation between control and experimental groups after wearing SCL. Fig. 1. Corneal topography map, (a) K-reading: 8.10 mm, 41.7 D, (b) K-reading: 9.37 mm, 36.0 D.
94 Ye-Rim Moon, Hyung-Min Park, and Byoung-Sun Chu Fig. 3. Changes of refractive power after wearing each type of SCL on the control group. Fig. 5. Comparison of corneal topography map variation between control and experimental groups after wearing SCL. 0.63 D, H2 0.49 D, S1 0.46 D, S2 0.53 D로나타났으며, H1 렌즈에서가장큰폭의변화가나타났고, S1 렌즈에서가장작은폭의변화가나타났다. 하지만렌즈재질별착용전과후의특이한변화를관찰할수없었고, 통계적으로유의한차이또한보이지않았다 (p=0.930). 3) 수술자의렌즈재질에따른굴절력변화량비교각막굴절교정수술자각막의렌즈착용전과각재질별렌즈착용후굴절력변화는 Fig. 4에서보여지는것과같이 H1 0.52 D, H2 0.86 D, S1 0.60 D, S2 0.67 D로나타났으며, H2 렌즈에서가장큰폭의변화가나타났고, 비수술자각막과는반대로 H1 렌즈에서가장작은폭의변화를보였다. 하지만수술자역시각렌즈의재질별착용전과착용후의특이한변화는관찰할수없었고, 통계적으로유의한차이를보이지않았다 (p=0.780). 3. 각막지형도변화 1) 렌즈착용후, 수술자와비수술자의각막지형도변화량소프트콘택트렌즈착용후수술자와비수술자의각막지형도변화량을비교해본결과 (Fig. 5) 수술자는렌즈착용전보다착용후각막지형도변화량이 3.72 D 만큼나타 났으며, 비수술자는 2.70 D 만큼의변화량이나타났다. 두그룹간의차이는 1.02 D 이였으며통계적으로유의한차이를보였다 (p=0.023). 2) 비수술자의렌즈재질에따른각막지형도변화량 Table 2~5에는콘택트렌즈를착용전과착용후각방향 Table 2. Average topography map variation of nasal zone in the control group according to the lens material Naked 42.938 42.500 42.325 41.825 40.771 H1 40.248 40.130 39.661 39.509 40.074 H2 40.091 39.761 39.483 39.052 39.357 S1 41.113 40.026 39.578 39.657 39.900 S2 40.558 40.217 40.029 39.858 39.550 Table 3. Average topography map variation of temporal zone in the control group according to the lens material Naked 42.938 42.542 42.438 42.008 40.996 H1 40.248 39.626 39.626 39.474 38.965 H2 40.091 39.678 39.639 39.352 38.809 S1 41.113 40.157 39.987 39.548 37.491 S2 40.558 40.113 40.075 39.775 39.129 Table 4. Average topography map variation of inferior zone in the control group according to the lens material Fig. 4. Changes of refractive power after wearing each type of SCL on the experimental group. Naked 42.938 43.775 43.604 43.154 42.146 H1 40.248 41.070 40.826 40.439 39.609 H2 40.091 41.057 40.770 40.448 39.678 S1 41.113 41.591 41.122 40.613 39.865 S2 40.558 41.450 41.163 40.883 40.088
Study of Masking Effect of Soft Contact Lenses on Cornea after Refractive Surgery 95 Table 5. Average topography map variation of superior zone in the control group according to the lens material Naked 42.938 44.321 43.696 43.263 42.167 H1 40.248 41.057 41.039 41.130 41.000 H2 40.091 41.243 40.926 40.783 40.652 S1 41.113 41.174 40.913 40.670 40.326 S2 40.558 41.467 41.421 41.271 40.571 Table 6. Average topography map variation of nasal zone in the experimental group according to the lens material Naked 38.740 38.448 38.492 39.428 40.212 H1 36.396 36.062 36.219 37.831 39.850 H2 36.165 35.777 35.869 36.977 38.788 S1 36.373 35.912 35.881 37.196 39.485 S2 36.650 36.196 36.312 37.535 39.027 Table 7. Average topography map variation of temporal zone in the experimental group according to the lens material Fig. 6. Comparison of corneal topography map variation between before and after wearing each type of SCL in control group. 즉, 코쪽 (nasal), 귀쪽 (temporal), 아래쪽 (inferior), 위쪽 (superior) 영역별비수술자각막지형도변화를나타내었다. Fig. 6에는비수술자의각막지형도변화량을각영역을토대로나타내었다. 각렌즈재질별각막지형도의변화량은나안과비교하여 H1 40.21 D, H2 40.05 D, S1 40.35 D, S2 40.46 D로하이드로겔렌즈에비해실리콘하이드로겔렌즈에서높은변화량을나타내었지만통계적으로유의한변화는보이지않았다 (p=0.415). 반면렌즈를착용하지않은상태 (42.6 D) 와각렌즈재질별착용후각막지형도의변화를비교해본결과통계적으로유의한변화량을나타냈다 (p=0.000). 3) 수술자의렌즈재질에따른각막지형도변화량렌즈를착용하지않은상태와각재질별콘택트렌즈착용후수술자각막지형도변화의평균값을 Table 6~9에나타내었다. Fig. 7에는수술자의각막지형도변화량각영역을토대로나타내었다. 각렌즈재질별각막지형도의변화량은 H1 40.58 D, H2 37.27 D, S1 38.91 D, S2 38.37 D로재질에상관없이 H1에서가장높은변화량을나타내었다. 비수술자의변화량과마찬가지로각렌즈재질별각막지형도의변화량은유의하지않았으나 (p=0.599), 렌즈를착용하지않은상태와각재질별콘택트렌즈착용후각막지형도변화량은유의하였다 (p=0.000). Naked 38.740 38.448 38.492 39.428 40.212 H1 36.396 36.400 36.850 37.558 38.735 H2 36.165 36.108 36.527 37.342 38.042 S1 36.373 36.250 36.773 37.512 38.446 S2 36.650 36.558 36.958 37.781 38.865 Table 8. Average topography map variation of inferior zone in the experimental group according to the lens material Naked 38.740 39.604 40.648 42.468 43.124 H1 36.396 37.450 38.069 39.896 40.754 H2 36.165 37.135 38.038 39.677 40.350 S1 36.373 37.596 38.454 39.762 40.708 S2 36.662 37.538 38.473 39.827 40.777 Table 9. Average topography map variation of superior zone in the experimental group according to the lens material Naked 38.740 39.092 39.432 40.516 41.524 H1 36.396 36.558 37.038 38.923 40.723 H2 36.165 36.358 36.515 37.850 39.292 S1 36.373 36.723 36.700 37.819 39.515 S2 36.650 36.908 37.035 38.342 39.800 콘택트렌즈의 Masking 효과에관한선행연구에서 Rigid lens는아주좋은 Masking 효과가나타나는동일한결과를보였으나, [19,20] 소프트콘택트렌즈에관한연구결과로 Masking 효과를기대할수없다는결과 [21] 와 Masking 효과를기대할수있다 [14] 는결과로, 소프트콘택트렌즈에관한연구결과가두가지로나뉘어있다. 본연구에서나
96 Ye-Rim Moon, Hyung-Min Park, and Byoung-Sun Chu 는기존연구를통해빛의양이현저히감소하는야간운전및야간시생활, [23] 또는흐린날이나비오는날과같은피지배적인환경에노출되었을경우제 2의위험군에노출될가능성이매우높다는것을알수있다. [24] 따라서각막굴절교정수술자들을위한소프트콘택트렌즈처방시 Masking 효과를고려하여렌즈를처방하여야한다. Fig. 7. Comparison of corneal topography map variation between before and after wearing each type of SCL in experimental group. 타난결과는각막곡률반경및렌즈재질에관계없이소프트콘택트렌즈착용자체만으로도 Masking 효과가나타났고이는소프트콘택트렌즈의 Masking 효과기대가능의선행연구결과 [14] 와일치하였다. 각막굴절교정수술로인하여편평해진각막형상을갖고있는수술자와비수술자간의굴절력을통한 Masking 효과연구에서수술자는비수술자보다 + 방향의굴절력이증가하였다. 또한각막지형도변화를통하여두그룹모두렌즈착용자체만으로 Masking 효과가나타남을알수있었다. 반면서로다른소프트콘택트렌즈재질에따른 Masking 효과의유의한차이는확인할수없었고, 선행연구 [17] 와는다른결과로나타났다. 이는현재출시되어지고있고본실험에서사용된렌즈의특성이 Table 1에서보여지는것과같이일반하이드로겔렌즈도실리콘하이드로겔렌즈와비슷한모듈러스를갖고있으며, 반대로실리콘하이드로겔렌즈도하이드로겔렌즈와비슷한모듈러스를갖고있기때문이다. 본연구를통하여수술자와비수술자모두렌즈착용자체만으로 Masking 효과가나타남을발견하였고, 소프트콘택트렌즈착용시재질에관계없이각막굴절교정수술자그룹에서 + 굴절력방향으로 Masking 효과가나타남으로비수술자의처방과차이를두어야한다는점을발견하였다. 본연구의제한점은네가지의서로다른모듈러스를가진렌즈만으로실험을진행하였고, 모듈러스외에다른렌즈들의특성들을고려하지않았기때문에향후추가적인데이터수집을통한연구를통해 Masking 효과에미치는다양한렌즈들의물리적특성에관한연구가필요할것이다. 각막굴절교정수술자들에게올바른소프트콘택트렌즈처방에의한 Masking 효과가실현되지못할경우, 각막굴절교정수술자들은불규칙한각막표면으로투과되는수차에의해시력의질에영향을미치게될것이며 [22], 이 결 론 각막굴절교정수술로인하여편평해진각막형상을갖고있는수술자와비수술자간의굴절력과각막지형도를통한 Masking 효과연구를통하여수술자는비수술자보다 + 방향의굴절력이증가하였고, 각막지형도를통하여두그룹모두소프트콘택트렌즈착용자체만으로 Masking 효과가나타났다. 반면서로다른소프트콘택트렌즈재질에따른 Masking 효과의통계적으로유의한차이는확인할수없었다. 따라서본연구를통하여각막굴절교정수술자들의소프트콘택트렌즈재착용시재질에관계없이 Masking 효과가나타남으로비수술자의처방과차이를두어야한다는점을발견하였다. REFERENCES [1] Hepsen IF, Evereklioglu C, Bayramlar H. The effect of reading and near work on the development of myopia in emmetropic boys: a prospective, controlled, three year follow up study. Vision Res. 2001;41(19):2511-2520. [2] Chung SK, Kang SB, Kim HK, Rho CR, Paik JS, Lee NY. Explanation of ophthalmic terminology, 1st Ed. Goyang: Naewaehaksool, 2010;177. [3] Korea National Health and Nutrition Examination Survey. Eye examination, 2008. https://knhanes.cdc.go.kr/knhanes/ sub03/sub03_02_02.do(1 October 2015). [4] Lee JH, Lee KS, Chu BS. Contact lens prescribing pattern in Korean during 2010 to 2013. J Korean Ophthalmic Opt Soc. 2014;19(3):323-329. [5] Ward MA. 20 years and beyond: a brief history of modern lenses. Contact Lens Spectr. 2006;21(6):49-51. [6] French K. Why is modulus important?, 2001. http://www.siliconehydrogels.org/editorials/oct_07.asp(12 October 2015). [7] Trokel SL, Srinivasan R, Braren B. Excimer laser surgery of the cornea. Am J Ophthalmol. 1983;96(6):710-715. [8] Ali JL, Belda JI, Osman AA, Shalaby AM. Topographyguided laser in situ keratomileusis (TOPOLINK) to correct irregular astigmatism after previous refractive surgery. J Refract Surg. 2003;19(5):516-527. [9] Sandoval HP, Castro LEF, Vroman DT, Solomon KD. Refractive surgery survey 2004. J Cataract Refract Surg.
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98 Ye-Rim Moon, Hyung-Min Park, and Byoung-Sun Chu 각막굴절교정수술안에대한소프트콘택트렌즈착용시 Masking 효과 문예림, 박형민, 추병선 * 대구가톨릭대학교안경광학과, 시기능증진연구소, 경산 38430 투고일 (2015 년 11 월 11 일 ), 수정일 (2016 년 3 월 15 일 ), 게재확정일 (2016 년 5 월 9 일 ) 목적 : 본연구는각막굴절교정수술후각막과수술을한적이없는각막형상에따른하이드로겔렌즈와실리콘하이드로겔렌즈착용시 Masking 효과를알아보고자하였다. 방법 : 실험에참여한 2 대상군은평균나이가 23.48± 2.89 세인정상적인각막형상그룹 (12 명, 통제그룹 ) 과각막굴절교정수술로인한편평한각막형상그룹 (LASIK-8 명, LASEK-4 명, 실험그룹 ) 으로구성된 24 명의대학생이였으며, 오른쪽눈의평균굴절이상은각각통제그룹 ( 정상각막형상 )RE: 2.73 D, 실험그룹 ( 편평한각막형상 )RE: 0.24 D 이었다. 두그룹에서 3.00 D 렌즈의 2 가지의하이드로겔렌즈 (0.89 Mpa, 0.49 Mpa) 와실리콘하이드로겔렌즈 (1.5 Mpa, 0.8 Mpa) 를사용하여착용전후의굴절력및각막지형도의차이를비교하였다. 측정에사용된장비로는 NVision-K5001(Shin-nippon, Japan) 로굴절력을측정하였으며, 각막지형도측정을위하여 Keratograph 5M(Oculus, Germany) 을사용하였다. 결과 : 굴절력변화는실험그룹에서 + 방향으로증가하였고, 각막지형도의변화는소프트콘택트렌즈착용후두그룹모두유의한변화를보였다 (p<0.05). 그러나렌즈재질별굴절력및각막지형도변화에서렌즈착용전후, 두그룹모두유의한변화를보이지않았다. 결론 : 소프트콘택트렌즈착용은각막지형도의차이는있었으며, 특히각막굴절교정수술후편평한각막은소프트콘택트렌즈착용시굴절력변화가크게나타났다. 따라서각막굴절교정수술자에게소프트콘택트렌즈처방을할경우굴절력변화에주의하여야한다. 주제어 : 실리콘하이드로겔렌즈, 모듈러스, 각막굴절교정수술, 불규칙각막난시, 각막지형도