Fourier Analysis And Research On The Effects Of Corneal Surface Morphology With Overnight Orthokeratology

Objective:To explore whether fourier analysis can be used as an effective method of preoperative and postoperative dynamic assessment of corneal topography data undergoing orthokeratology treatment by Fourier Map. To study the effects of the orthokeratology contact lens on the corneal surface morphology and to figure out the mechanism of treating and preventing the development of myopia. Method: Review January 2012-October 2013 in our hospital have weared Orthokeratology lens with refractive errors patients, select the range of refractive status : spherical equivalent was-0.75 ~-6.75 DS, an average of-3.30 ± 1.51; rule astigmatism ≤-2.50 DC, against the rule astigmatism ≤-1.50 DC, and no more than half of myopia; corneal curvature range of 38.00 to 47. OOD; Best corrected visual acuity ≥ 5.0; total of 52 patients, 94 were male and 21 cases( 38) and 31 females( 56); aged 8 to 25 years, mean 13.5 ± 4.05 years old. Patients were recorded before wearing glasses, wearing glasses 1, 1 week, 1 month, 3 months, 6 months after visual acuity, TMS-4 corneal topography test results, statistical analysis of Fourier topographic index changes. Result: In the six months of follow-up observation spectacles : the value of wearing 3mm area Spherical day 41.75 ± 1.46, with an average reduction of 1.42 ± 0.67,6 mm area Spherical value reduced by an average 42.25 ± 1.41 and 0.7 ± 0.39,3 mm mean difference 0.26 ± 0.17 6mmSpherical; wearing one week 3mm value 41.31 ± 1.59 Spherical region, with an average reduction of 2.20 ± 0.84,6 mm area Spherical value reduced by an average 42.10 ± 1.50 and 1.14 ± 0.43,3 mm 6mmSpherical mean difference-0.5 ± 0.41; wearing January 3mm area Spherical value 41.07 Guests 1.72, with an average reduction of 2.42 ± 1.09,6 mm area Spherical value reduced by an average 41.91 ± 1.50 and 1.31 ± 0.61,3 mm 6mmSpherical mean difference-0.79 ± 0.43; wearing three months 3mm and 6mmSpherical mean difference-0.87 ± 0.61; wear 3mm half mirror and 6mmSpherical average difference-1.00 ± 0.49. Compared with baseline data, after wearing 3mm and 6mmSpherical index difference P <0.05, statistically significant. Conclusion: 1、The Fourieranalysis method was successfully applied to quantitative assessment on the corneal surface morphology in the preoperative and postoperative of Orthokeratology 2、Fourier analysis map shows that orthokeratology topographic maps by changing the shape and curvature of the corneal surface, reducing myopia, improve visual acuity, fast-acting, a significant effect. 3、Fourier analysis map of topographic maps show orthokeratology lens on the central and peripheral cornea to correct refractive errors of different effects, which may be one of the main reasons to slow down the myopia progression.