Vol. 17, No. 3, pp. 265-272, September 2012? da»w z w y» 1 û w œw, Ÿ 500-757 2 w Ÿw, Ÿ 500-714 nš (2012 7 31 ), (2012 9 12 ), y (2012 9 15 ) : ƒ ƒ»w jš ù z z w š w. : 7 15 2.00 D w 19 (Group 1) 2.25 D 4.00 D w 28 (Group 2), 4.25 D 15 (Group 3), 31 (62 )»w, z 1, 1, 3, 6 z ù ƒ x y 3 ù z š w m wš w. :»w wš ù z Group 1 z 1 0.45 0.95 0.50 w 1 0.91, 3 1.02 w ù 6 0.95 w. Group 2 z 1 0.34 0.77 0.43 w, 1 0.91 ƒ, 3 0.97 ¾ w 6 ¾ m. Group 3 z 1 0.15 0.70 0.55 w, 1 0.87, 3 0.91 w ù 6 0.86. ƒ x s³ Sim K(simulated keratometry reading) Group 1 42.84Û1.17 D z 1 41.48Û0.98 D w 3 ¾ w ƒ 6 ƒw. Group 2 42.91Û1.57 D z 1 41.78Û1.58 D, 3 ¾ w ƒ 6 ƒw. Group 3 42.64Û1.64 D 40.77Û1.20 D z 1 w š 1 z ƒw ƒ 3 w 6 ¾ w. :»w z 1 l z ƒ z» ƒ ù z ƒ ù kû. :»w, z, ƒ x,»w (RGL, reverse geometry contact lens) gk p š ƒ ƒ š rsw w, w»w w j ƒ (orthokeratology) š w. [1] 1962 Jessen w Orthofocus z n š ƒ ƒq š»w ƒ š.»w ƒ š y g ƒ rsyw w. [2]»w Ÿw (Optic zone),» w f (reverse curve), f (alignment curve), f (peripheral curve) 4 ù, š ƒ w w»w f (reverse curve) ƒ d ƒ œ w w ƒ z j w w. w f ƒ ƒ» [3]» w w w. f (alignment curve) ƒ j z y j wš f (peripheral curve) ƒ (edge lift)» wš y w w. w ƒ [4] w y w û ù w š w k ƒ š ƒ t š. [5,6] Mountford»w z 1 *Corresponding author: Min-Hwa Yoon, TEL: +82-17-640-7211, E-mail: oberon73@hanmail.net 265
266 y,» w yƒ š w š[7] Soni z 3 y w š šw. [8], Nichols 1 ü z ƒ 1 y š šw. w [9] Chang z z 1 z l z» w 6 z z ùk ü š w w z ƒ š š ù, w z w w dw» š š š š. [3] w Carkeet w šw ƒ z, ƒ v w, ƒ Ì, ƒ j», š ƒ š w. ƒ z ƒ, ƒ» d ƒ š w. z [10] 1, 3 d e 2.00 D w ƒ 4.00 D w š w.»w ƒ [5] 5.00 D w w z ƒ š w. [11] Soni [8] 4.00 D 1 ƒ w z ƒ ùkû š w, [11] x 3.50 D w z 1, 3.50 D 5.00 D w 2 š w. 2.00 D 4.00 D» w 2.00 D w 4.25 D ù z.»w w ƒ û z ƒ w z tƒ 5.00 D z ƒ w» w w z z ù ƒ x mw š w. 1. 2007 3 l 2012 6 ¾ Ÿ w»w 7 15 6 ƒ w 31 (62 ) w. 1.00 D 6.25 D w, ù 2.00 D w ƒ š» 46.00 D(7.34 mm) 39.75 D(8.50 mm), ƒ y 11.5 mm 2 x z x ƒ 1 7 wš ew y w. w ƒ 2.00 D w (Group 1) 2.25 D 4.00 D w (Group 2), 4.25 D (Group 3) ù z w., y x gkp w x w. w ƒ e ù, x w ƒ w š q ƒ w 2 z w w. 2. 1)»»w w»» w.»w w» 120 cd/m 2 6 m s l n t w t ƒ ww d w š (spherical power) ù (cylinderical power) 1/2 w ƒ w. mw ƒ k y z wwš,» (auto ref-keratometer RK-5, CANON, JAPAN) w x, ƒ š d ƒ x (oculus keratograph) ww. 2)»w Lusid Korea LK-CH Table 1. Characteristics of OK lens Trade name LUCID CH 2 Manufacturer LUCID CO. Material Hexacon A (fluorosilicone acrylate) Dk o value 140 Dk/L o 70 Center thickness 0.2 Hardness 112 Water absorption(%) 4.9 Diameter(mm) 10.0~10.6 RGL : Revese geometry lens. o Oxygen permeability coefficient (cmámlo 2 )/(secámlámmhg)á10 11 value o Oxygen transmissibility coefficient (cm/mlo 2 )/(secámlámmhg)á10 9
»w z w 267 (Lusid, CH 2, Korea) w (Table 1). Hexacon A(fluorosilicone acrylate) Dk(PTC gas to gas) valueƒ 140(cmÁmlO 2 )/(secámlámmhg)á10 11. x e» w, ƒ š e ƒ x z x k z v xÿ w (Central alignment zone) 6 mm, vq (fitting zone) 1.0 mm, (peripheral curve) 0.4 mmƒ wš À 1.0~2.0 mm kw. k wš k w 1 z š ù, ƒ š,, ƒ xk w z z dw w. 1 7 w š ew w z e z w», z 1, 1, 3, 6 z ù ƒ x d w. 3. m m»w w», z 1, 1, 3, 6 z w t T, ù w ƒ z, ƒ x Sim K(simulated keratometry reading) w ƒ z d w w š, x w ü z w m w x w mw p<0.05 m w š q w. w z mw y w w k ƒ ƒƒ ù ƒ x z p<0.05 m w š q w. š 31 (62 ) û 8 (16 ), ƒ 23 (46 ) š, s³ ù 10.48Û 2.15(7~15 ). s³ ƒ 3.64Û1.26 D, ƒ Ì 554.69Û35.08 µm ùkû Table 2. Subject characteristics Subject characteristics MeanÛSD Age(range) 10.48Û2.15(7~15) Gender ratio(m:f) 31(8:23) Refractive error(se) Central corneal thickness(m) 3.64Û1.26 554.69Û35.08 Table 3. Distribution of baseline uncorrected visual acuity in the 62eyes Baseline UCVA 0.05~0.2 0.3~0.4 0.5~0.6 0.7 UCVA : uncorrected visual acuity. No of eyes (percent) 41.94 24.19 22.58 11.29 Table 4. Distribution of myopia in the 62 eyes Spherical Equivalent No of eyes (percent) Group 1 Group 2 ß 1.0 D 1.25 ~ 2.0 D 2.25 ~ 3.0 D 3.25 ~ 4.0 D 0 31.03 25.86 18.96 Group 3 à 4.25 D 24.15 (Table 2). 62 w ù s 0.05~0.2 41.9%, 0.3~0.4 24.19%, 0.5~0.6 22.58%, 0.7 11.29% ùkû (Table 3). 1.00 D š 2.00 D w Group 1 31.03%(19 ), 2.25 D š 4.00 D w Group 2 44.82%(28 ), 4.25 D Group 3 24.15%(15 ) ùkû (Table 4). ƒ gkp w ƒ xk y g ù w w ù. ƒ» 1956 Morrison ƒ rsw ƒ d e 1.50 D 2.50 D¾ rsw polymethylmethacrylate(pmma) g 2» w. [5] ƒ rsw j ù x»w š, ƒ w.»w g ƒ y w wš û w k w w.»w z w,»w z 1 ¾ m w w ù z»w 3 z z 1 w ù w x ùkþ š w š, w w»w [12] z 3 z»w w ƒ w z ƒ w š šwš. [3]
268 y,» Table 5. Uncorrected visual acuity in group 1~3 Uncorrected visual acuity Mean/SD p-value * baseline 0.45Û0.18 1 week 0.95Û0.17 P<0.05 Group 1 1 month 0.91Û0.23 P<0.05 3 months 1.02Û0.18 P<0.05 6 months 0.95Û0.19 P<0.05 Group 2 Group 3 baseline 0.34Û0.16 1 week 0.77Û0.19 P<0.05 1 month 0.91Û0.12 P<0.05 3 months 0.97Û0.12 P<0.05 6 months 0.97Û0.19 P<0.05 baseline 0.15Û0.15 1 week 0.70Û0.30 P<0.05 1 month 0.87Û0.11 P<0.05 3 months 0.91Û0.13 P<0.05 6 months 0.86Û0.13 P<0.05 UCVA: uncorrected visual acuity. Group 1: baseline refractive error ß 2.00 D. Group 2: baseline refractive error > 2.00 D. ~ ß 4.00 D. Group 3: baseline refractive error > 4.00 D. * p-value (comparison of Uncorrected visual acuity between the results of baseline and 6months after wearing reverse geometry lens by paired t test(p<0.05) Mountford overnight basis»w z ƒ s³ +2.19 D w d ƒ wš w w š šw 1 ü w yƒ š 3 z ƒ w š šw. [7] Nichols RGP w overnight orthokeratology w Fig. 1. Uncorrected visual acuity at baseline, 1 week, 1 month, 3 months and 6 months during wearing reverse geometry lens. w w z m 1 ü z ƒ 30 y š šw. z 1 ü [9] w, x Æ3.50 D 1, 3.50 D 5.00 D w 2 ü y. [11] Table 5 Fig. 1 ù ù kü»w Group 1 s³ ù 0.45Û0.18, Group 2 0.34Û0.16, Group 3 0.15Û0.15 w Group 1 z 1 0.45 0.95 0.50 w j ƒq ùkû, z 3 1.0 w z 6 0.95 w (P<0.05) w. Group 2 z 1 0.34 0.77 0.43 w, 1 0.91 w ƒ š, 3 0.97 ¾ w 6 ¾ m (p<0.05)w. Group 3 z 1 0.15 0.70 0.55 w, 1 0.87, 3 0.91 w ù 6 0.86 w (p<0.05). Table 6. Uncorrected visual acuity after reverse geometry lens wearing in Group 1~3 Follow-up Follow-up UCVAà0.8 Group 1 Group 2 Group 3 UCVAà1.0 UCVAà0.8 UCVAà1.0 UCVAà0.8 UCVAà1.0 p-value 1 week 1 month 3 months 6 months 86.6 73.3 93.3 86.6 73.3 60 73.3 60 53.5 85.7 96.4 85.7 53.3 53.5 60.7 67.8 64.2 85.7 85.7 78.5 21.4 28.5 42.8 35.7 0.016 * 0.040 & 0.001 @ UCVA: uncorrected visual acuity. Group 1: baseline refractive error ß 2.00 D. Group 2: baseline refractive error > 2.00 D. ~ ß 4.00 D. Group 3: baseline refractive error > 4.00 D. * p-value (UCVA à 1.0 in Group 1 vs UCVA à 1.0 in Group 2 by Repeated measure) & p-value (UCVA à 1.0 in Group 2 vs UCVA à 1.0 in Group 3 by Repeated measure) @ p-value (UCVA à 1.0 in Group 3 vs UCVA à 1.0 in Group 1 by Repeated measure)
»w z w 269 ù y d w m (p<0.05)w y ùkþ, w ù y ùkù (p>0.05). Table 6 ù w z Group 1 1.0 ¾ 60%, 73.3%ƒ w, Group 2 1.0 ¾ 53.3%, 67.8%ƒ w š, Group 3 1.0 ¾ 21.4%, 42.8%¾ w w. Group 1 Group 2 ù w z ƒ w š(p>0.05), Group 2 Group 3 w ùkû (p<0.05), Group 3 Group 1 w ùkû (p<0.05). Group 1 z 1 l 0.90 w z ƒ Group 2 1 0.90 w 2.00 D z. Group 3 3 0.90 w. w w ƒ ù m w (p>0.05). 1 z ù 0.80 ƒ 80% 1 ƒ w w š 3 ¾ 1 z y rw 0.80 z w ƒ 2.00 D w Group 94% 2.00 D 4.00 D w Group 70% w w f, z 1, 3 d e ƒ û ù m w š w, ƒ ù. Group 1 j Group 1 ƒ Group 2 w» Group 2 ù ù» w. [5] Soni»w s³ 3.00 D ƒ w š 1 z ƒ y z ƒ še š w w tw. ü y [8] LK-DM w 24 ü ù 0.80 ƒ 70% š w š, x [13] 3.50 D w z 1, 3.50 D 5.00 D w 2 š w. [11] 3 z 6 z w m w w x, Group 1 Group 2, Group 3 3 š w z 6 w w. w»w wš 1 z z š, z ƒ 6 3 w m w w x š w. [3] ù ù ü ù m w ù y 1 3 m w ù ù z j ùkû œ»w z y ùkù, ù ù y j ùk û. [14] ƒ x s³ Sim K(simulated keratometry reading) Group 1 42.84Û1.17 D z 1 41.48Û0.98 D w 3 ¾ w ƒ 6 (p<0.05)w ƒw. Group 2 42.91Û 1.57 D z 1 z 41.78Û1.58 D, 3 ¾ w ƒ 6 (p<0.05)w ƒw. Group 3 42.64Û1.64 D 40.77Û1.20 D z 1 w š 1 z ƒw ƒ 3 w 6 ¾ (p<0.05)w w. ƒ x y Group 1 w z 1 1.38 D w š, 1 z 1.44 D, 3 z 1.20 D, 6 1.03 D w z 1 z ƒ w ùkû. Group 2 w 1 z 1.13 D w š, 1 z 1.22 D, 3 z 1.37 D, 6 z 1.26 D w 3 z ƒ w ùkû. Group 3 w z 1 z 1.87 D, 1 z 1.80 D, 3 z 2.34 D, 6 z 2.08 D j w 3 zƒ z ƒ w ù kû (Table 7, Fig. 2). ƒ w wš 3 6 ƒ»w w ƒ Ì y w, vq d w ƒ e ƒ ƒ. ƒ x y d w m (p<0.05)w y ù kü w ƒ x y m p=0.11 w yƒ ùkù. s³ Sim K(simulated K-reading)»w
270 y,» Table 7. Topography in group 1~3 Group 1 Group 2 Group 3 Topography MeanÛSD p-value * baseline 42.84Û1.17 1 week 41.48Û0.98 P<0.05 1 month 41.4Û0.89 P<0.05 3 months 41.64Û0.87 P<0.05 6 months 41.81Û1.21 P<0.05 baseline 42.91Û1.57 1 week 41.78Û1.58 P<0.05 1 month 41.69Û1.51 P<0.05 3 months 41.54Û1.52 P<0.05 6 months 41.65Û1.43 P<0.05 baseline 42.64Û1.64 1 week 40.77Û1.20 P<0.05 1 month 40.84Û1.41 P<0.05 3 months 40.6Û1.33 P<0.05 6 months 40.56Û1.13 P<0.05 Group 1: baseline refractive error ß 2.00 D. Group 2: baseline refractive error > 2.00 D. ~ ß 4.00 D. Group 3: baseline refractive error > 4.00 D. * p-value (comparison of Topography between the results of baseline and 6months after wearing reverse geometry lens by paired t test (P<0.05) Fig. 2. Topography at baseline, 1 week, 1 month, 3 months and 6 months during wearing reverse geometry lens. 43.10Û0.72 D 2 z 41.61 Û0.82 D w m w w š w. [11] ƒ š d ƒ rsy 1 z w š s³ 44.40Û1.80 D 3 z 43.38Û1.32 D w w ƒ x 0.49Û0.07 0.09Û 0.21 w w ƒ ƒ ƒ š ƒ ƒw ƒ y(sphericalization) ƒ rsy š w. [5]»w ƒ,,, ƒ yk š w. [5,11] w k, ƒ, ƒ e [3] z 3» 4 ƒ td ƒ w ù w p z w. ù w À ƒ ƒ w w ƒ, ƒ, ƒ w ƒ» w ƒw š ü ƒ 1 w 11 ƒ ww š. [5] ƒ ù ƒ ƒ 2 w 2 z w w w w.»w wš ù z Group 1 z 1 3 ¾ w š 6 z. ƒ x z 1 3 ¾ w ƒ 6 ƒw. Group 2 z 1 3 ¾ w 6 ¾ m z ƒ. ƒ x z 1 3 ¾ w ƒ 6 ƒw. Group 3 z 1 3 ¾ w ù s Group w z ƒ ùkûš 6 ƒ z. ƒ x z 1 w š 1 z ƒw ƒ 3 w 6 ¾ w.»w z 1 l z ƒ z» ƒ ù Group z ƒ ùkû. 6 ¾»w z, wz 6 z z w ƒ w, p 6 z y w ƒ v w ƒ. w w.
»w z w 271 REFERENCES [1] Shin DB, Lee YW, Kim MK, Kim SY, Lee JL, Choi SW. The effect of RGP lens and reverse geometry lens on corneal epithelial proliferation rate in rabbit. J Korean Ophthalmol Soc. 2004;45(4):655-667. [2] Jessen GN. Orthofocus techniquea. Contacto. 1962;6:200-204. [3] Chang JW, Choi TH, Lee HB. The Efficacy and Safety of Reverse Geometry Lenses. J Korean Ophthalmol Soc. 2004;45(6):908-912. [4] Lee SJ, Park SJ, Chun YY. The change in corneal eccentricity on the correction of refractive error using reverse geometry lens. J Korean Oph Opt Soc. 2010;15(2):145-150. [5] Wie HY, Lee DH, Kim JM. The efficacy and safety of dream lens TM in school children. J Korean Ophthalmol Soc. 2004;45(6):913-919. [6] Mun MY, Lee KJ, Lee JY. The effect of refractive and corneal recovery after discontinuation of orthokeratology contact lenses in children. J Korean Oph Opt Soc. 2009; 14(3):7-15. [7] Mountford J. An analysis of the changes in corneal shape and refractive error induced by accelerated orthokeratology. Int Contact Lens Clin. 1997;24(4):128-144. [8] Soni PS, Nguyen TT, Bonanno JA. Overnight orthokeratology: visual and corneal changes. Eye Contact Lens. 2003;29(3):137-145. [9] Nichols JJ, Marsich MM, Nguyen M, et al. Overnight orthokeratology. Optom Vis Sci. 2000;77(5):252-259. [10] Carkeet NL, Mountford JA, Carney LG. Predicting success with orthokeratology lens wear: a retrospective analysis of ocular characteristics. Optom Vis Sci. 1995;72(12): 892-898. [11] Shin DB, Yang KM, Lee SB, Kim MK, Lee JL. Effect of reverse geometry lens on correction of moderate-degree myopia and cornea. J Korean Ophthalmol Soc. 2003;44(8): 1748-1756. [12] Lee SJ, Park SJ, Park HJ. The study of wearing effect of reverse geometry lenses for myopic children. J Korean Vis Sci. 2010;12(3):191-198. [13] Jee DH, Hong ME, Kim MS. The efficacy and safety of ortho-k LK TM lens. J Korean Ophthalmol Soc. 2003; 44(3):706-711. [14] Na JH, Choi JH, Yang JW, Lee YC, Kim SY. The relationship between asphericity and visual acuity after wearing reverse-geometry lens. J Korean Ophthalmol Soc. 2009; 50(5):670-676.
272 y,» A Comparative Study on the Effects of Wearing Reverse Geometry Lenses by Degrees of Myopia Min-Hwa Yoon 1,2, and Ki-young Lee 1 1 Dept. of Biomedical Engineering, Chonnam University, Gwangju 500-757, Korea 2 Dept. of Optometry and Optic Science, Dongkang College, Gwangju 500-714, Korea (Received July 31, 2012: Revised September 12, 2012: Accepted September 15, 2012) Purpose: To compare the results on myopia correction with reverse geometry lenses, effects of wearing reverse geometry lenses were evaluated for the children with low-level and high-level myopia. Methods: The research investigated the corrective effects of having worn reverse geometry lenses for one week, one month, three months and six months on a total of thirty-six persons (sixty-two eyes) between the ages of seven and fifteen, divided into three groups by the degree of their myopia; nineteen eyes(group One) with myopia of 2.00 D and under, twenty-eight eyes(group Two) with myopia between 2.25 D and 4 D, and fifteen eyes(group Three) with myopia of 4.25 D and above; as shown by changes in uncorrected vision and the degree of refraction in the corneal topography, and tested for statistical similarity among the pursued results. Results: After wearing reverse geometry lenses, Group One showed an improvement in vision of 0.5, from 0.45 to 0.95, after one week, and improvements to 0.91 after one month and 1.02 after three months but, after six months, the group's vision regressed to 0.95. Group Two showed an improvement in vision of 0.43, from 0.34 to 0.77, after one week of wearing and to 0.91 after one month, to 0.97 after three months and this was statistically maintained through the remainder of six months. Group Three showed an improvement in vision of 0.55, from 0.15 to 0.7, after wearing for one week, to 0.87 after one month and to 0.91 after three months but saw a regression to 0.86 after six months. The average Sim K (simulated keratometry reading) value for Group One started from 42.84Û1.17 D and decreased to 41.48Û0.98 D after one week of wearing and continued declining through three months before increasing during the remainder of six months. Group Two began from 42.91Û1.57 D and recorded 41.78Û1.58 D after one week, continuing the decline through three months before increasing during the remainder of six months. Group Three began at 42.64Û1.64 D and showed its Sim K value decrease to 40.77Û1.20 D after one week of wearing, increase after one month and decrease after three months and continue the decline through the remainder of six months. Conclusions: From the results of this study, wearing reverse geometry lenses had myopia-correcting effects after one week of wearing. Although there were variations in the time for such effect to take place but myopia-correcting effects were evident in all test groups. Key words: Reverse geometry lenses, Myopia-correcting effects, Corneal topography, Degree of refraction