Purpose: To evaluate the amount of lens decentration and various factors affecting decentration after orthokeratology lens wear and to observe the effect of decentration on the visual functions.Methods: Two kinds of o...Purpose: To evaluate the amount of lens decentration and various factors affecting decentration after orthokeratology lens wear and to observe the effect of decentration on the visual functions.Methods: Two kinds of orthokeratology lenses were fitted to 270 eyes of 135 patients [initial mean refractive error: (-3.98±1.51)D]. Humphery Instruments ATLAS 990 was used for the computer-assisted analysis of corneal topographical maps. The examination of corneal topography was performed on patients before and after 6 months of wearing orthokeratology lenses. The amount of decentration of orthokeratology lenses was measured by finding the distance between center of optic zone and the pupil center. The factors influencing the amount of decentration were analyzed, including the initial refraction error, astigmatism, keratometry values, corneal eccentricity, and the diameter of lens.Visual symptoms including monocular diplopia, glare around lights were recorded to evaluate the effects of decentration on visual functions.Results: The mean amount of decentration was (0.49±0.34) mm after one night's wear.The mean amount of decentration after 1 month, 3 months and 6 months was (0.57±0.41) mm, (0.55±0.48) mm and (0.59±0.39) mm, respectively. After one month, the amount of decentration was less than 0.50 mm in 51.1% eyes, 0.50～1.0 mm in 35.6% eyes and more than 1.00 mm in 13.3% eyes. The direction of decentration of more than 0.50 mm was mainly in the temporal quadrant (48.5%). Patients with greater initial astigmatism and smaller lenses showed greater decentration (P＜0.05). There was no statistically significant difference in decentration between the two groups with different corneal eccentricities and keratometry values (P＞0.05). The amount of decentration was greater in patients who complained of monocular diplopia and glare.Conclusions: The amount of decentration of orthokeratology depends on the initial refractive error, astigmatism and the design of orthokeratology lenses. Improvement in fitting technology and le展开更多
Background:This retrospective study was designed to investigate the sole influence of orthokeratology(OK)lens fitting decentration on the Zernike coefficients of the reshaped anterior corneal surface.Methods:This stud...Background:This retrospective study was designed to investigate the sole influence of orthokeratology(OK)lens fitting decentration on the Zernike coefficients of the reshaped anterior corneal surface.Methods:This study comprised a review of 106 right eyes and measurements of corneal topography both before OK and at 1-month follow-up visit.A routine was designed to calculate local corneal surface astigmatism and assist the determination of OK lens fitting decentration from pupil center.The pupil-centered corneal Zernike coefficients of baseline(PCCB)and post-treatment(PCCP)were calculated.Meanwhile,the OK-lens-centered corneal Zernike coefficients of post-treatment(OCCP)were also calculated and considered as the presumptive ideal fitting group without decentration.Relationships between lens fitting decentration and the change of Zernike coefficients including(PCCP−PCCB)and(PCCP−OCCP)were analyzed.Results:Patients with a mean age of 11±2.36 years old had an average spherical equivalent refractive error of−3.52±1.06 D before OK.One month after treatment,OK lens fitting decentration from pupil center was 0.68±0.35 mm.RMS of 3rd-order(P<0.05),RMS of 4th-order(P<0.001)and RMS of total high order(P<0.001)corneal Zernike coefficients were increased in PCCP by comparing with OCCP,which was solely caused by lens fitting decentration.Nevertheless,no significant difference was observed in C^(0)_(2)(P>0.05).For the high order corneal Zernike coefficients in(PCCP–OCCP),radial distance of decentration was correlated with C^(−1)_(3)(r=−0.296,P<0.05),C^(1)_(3)(r=−0.396,P<0.001),and C^(0)_(4)(r=0.449,P<0.001),horizontal decentration was significantly correlated with C^(1)_(3)(r=0.901,P<0.001)and C^(1)_(5)(r=0.340,P<0.001),and vertical decentration was significantly correlated with C^(−1)_(3)(r=0.904,P<0.001).Conclusions:OK lens fitting decentration within 1.5 mm hardly influenced the change of corneal spherical power for myopia correction,but significantly induced additional corneal high order Zernike coefficien展开更多
文摘Purpose: To evaluate the amount of lens decentration and various factors affecting decentration after orthokeratology lens wear and to observe the effect of decentration on the visual functions.Methods: Two kinds of orthokeratology lenses were fitted to 270 eyes of 135 patients [initial mean refractive error: (-3.98±1.51)D]. Humphery Instruments ATLAS 990 was used for the computer-assisted analysis of corneal topographical maps. The examination of corneal topography was performed on patients before and after 6 months of wearing orthokeratology lenses. The amount of decentration of orthokeratology lenses was measured by finding the distance between center of optic zone and the pupil center. The factors influencing the amount of decentration were analyzed, including the initial refraction error, astigmatism, keratometry values, corneal eccentricity, and the diameter of lens.Visual symptoms including monocular diplopia, glare around lights were recorded to evaluate the effects of decentration on visual functions.Results: The mean amount of decentration was (0.49±0.34) mm after one night's wear.The mean amount of decentration after 1 month, 3 months and 6 months was (0.57±0.41) mm, (0.55±0.48) mm and (0.59±0.39) mm, respectively. After one month, the amount of decentration was less than 0.50 mm in 51.1% eyes, 0.50～1.0 mm in 35.6% eyes and more than 1.00 mm in 13.3% eyes. The direction of decentration of more than 0.50 mm was mainly in the temporal quadrant (48.5%). Patients with greater initial astigmatism and smaller lenses showed greater decentration (P＜0.05). There was no statistically significant difference in decentration between the two groups with different corneal eccentricities and keratometry values (P＞0.05). The amount of decentration was greater in patients who complained of monocular diplopia and glare.Conclusions: The amount of decentration of orthokeratology depends on the initial refractive error, astigmatism and the design of orthokeratology lenses. Improvement in fitting technology and le
基金supported by the Scientific and Technological Program of Wenzhou[Y20160438,G20160033]National Natural Science Foundation of China[61775171]+1 种基金Natural Science Foundation of Zhejiang Province[LY14F050009,LY16H120007]National Key Research and Development Program of China[2016YFC0100200].
文摘Background:This retrospective study was designed to investigate the sole influence of orthokeratology(OK)lens fitting decentration on the Zernike coefficients of the reshaped anterior corneal surface.Methods:This study comprised a review of 106 right eyes and measurements of corneal topography both before OK and at 1-month follow-up visit.A routine was designed to calculate local corneal surface astigmatism and assist the determination of OK lens fitting decentration from pupil center.The pupil-centered corneal Zernike coefficients of baseline(PCCB)and post-treatment(PCCP)were calculated.Meanwhile,the OK-lens-centered corneal Zernike coefficients of post-treatment(OCCP)were also calculated and considered as the presumptive ideal fitting group without decentration.Relationships between lens fitting decentration and the change of Zernike coefficients including(PCCP−PCCB)and(PCCP−OCCP)were analyzed.Results:Patients with a mean age of 11±2.36 years old had an average spherical equivalent refractive error of−3.52±1.06 D before OK.One month after treatment,OK lens fitting decentration from pupil center was 0.68±0.35 mm.RMS of 3rd-order(P<0.05),RMS of 4th-order(P<0.001)and RMS of total high order(P<0.001)corneal Zernike coefficients were increased in PCCP by comparing with OCCP,which was solely caused by lens fitting decentration.Nevertheless,no significant difference was observed in C^(0)_(2)(P>0.05).For the high order corneal Zernike coefficients in(PCCP–OCCP),radial distance of decentration was correlated with C^(−1)_(3)(r=−0.296,P<0.05),C^(1)_(3)(r=−0.396,P<0.001),and C^(0)_(4)(r=0.449,P<0.001),horizontal decentration was significantly correlated with C^(1)_(3)(r=0.901,P<0.001)and C^(1)_(5)(r=0.340,P<0.001),and vertical decentration was significantly correlated with C^(−1)_(3)(r=0.904,P<0.001).Conclusions:OK lens fitting decentration within 1.5 mm hardly influenced the change of corneal spherical power for myopia correction,but significantly induced additional corneal high order Zernike coefficien
