| Part 1:Observe the safety of orthokeratology contact lens on myopia progression in teenager Purpose:To observe the conjunctiva, cornea complication, change of corneal thickness and corneal endothelium in myopic children wearing orthokeratology contact lenses(OK). Methods:Eighty-four myopia patients(only took the right eye data) wore OK lens. Cornea and conjunctiva complications after wearing OK lens two years were collected. The change of corneal thickness and corneal endothelium of forty myopia patients before and after wearing OK lens two years and four years were compared. Results:There were 73 cases(86.9%) completed the follow-up study in OK lens group. Cornea and conjunctiva complications: there were 20 cases of 0-II grade mild corneal staining which was the most common complications, three cases of III-IV grade corneal staining, five cases of corneal indentation, four cases of visual ghosting and glare at night, three cases reactive conjunctiva hyperemia, one case of corneal infiltrates aseptic, one case of allergic conjunctivitis, one case of corneal infection. All of the complications were recovered after normal treatment. The thinnest point of central corneal average thickness was(539.2 ± 39.5) μm,(528.7 ± 30.10) μm and(530.5 ± 32.4) μm before wearing OK, after wearing 2 years and after wearing 4 years, respectively. There was slight degressive trend after wearing OK lens of the central corneal average thickness, but the difference was not statistically significant(F=5.74, P=0.08). The corneal endothelial cell density was(3230.5±298.2) /mm2,(3195.9±270.9) /mm2 and(3219.4±285.3) /mm2 before wearing OK lens and after wearing 2 years and after wearing 4 years, respectively. The difference between them was not statistically significant(F=3.12, P=0.11). The average area of corneal endothelial cells was(320.5 ± 30.5) mm2,(322.1±31.6) mm2 and(318.3±29.5) mm2 before wearing OK, after wearing 2 years and after wearing 4 years,respectively.The difference between them was not statistically significant(F=5.42,P=0.21). The variation coefficient of corneal endothelial was(0.26 ± 0.03),(0.28±0.04) and(0.25±0.02) before wearing OK, after wearing 2 years and after wearing 4 years, respectively. The difference was not statistically significant between them(F = 1.04, P = 0.06). The corneal endothelial hexagonal cell was befor(65.2 ± 11.1)%,(63.6±13.3) % and(64.3±12.6) % before wearing OK, after wearing 2 years and after wearing 4 years, respectively. The difference was not statistically significant between them(F = 4.86, P = 0.16). Conclusions:The myopic children wearing OK lenses at night for short term was very safe that without serious corneal, conjunctival complications and had little effect on corneal endothelial cells. Part 2: Observe the efficacy of orthokeratology contact lens on myopia progression in teenagers Purpose:To observe the efficacy of wearing orthokeratology contact lenses(OK) in myopic children. Methods:This was a prospective non-randomized study. Eighty-four and eighty-two myopia patients(only took the right eye data) wore full correction single-vision spectacles(SV) and OK lens, respectively. Gender, age, baseline myopia and axial length(AL) at baseline and 3 years after wearing OK were collected. Results:There were 73 cases(86.9%), 70 cases(85.4%) completed the follow-up in OK lens group and single-vision spectacles group, respectively. Change in AL was(0.14±0.12) mm and(0.15±0.13) mm in the first and second year for the OK group(P >0.05). Thirty cases were followed up three years and there were no significant statistically significant differences between three years. Change in AL was(0.31±0.19) mm and(0.30±0.18) mm in the first and second year(P>0.05) for the SV group. Twenty-eight cases were followed up three years and there were no significant statistically significant differences of AL growth for the three years. There was a descend trend for the growth of annual AL(P <0.05). The diffrernce between OK and SV group of annual growth AL were statistically significantn(t=-3.81,-2.93,-2.64, P<0.05). Conclusions:The myopic children wearing OK lenses at night were effective for controling the myopia development. Compared to SV group, percentage of slow progression of AL was 52%, 51%, 48%, respectively in the first, second and third year in the OK group.Part 3: Factors preventing myopia progression with orthokeratology correction Purpose:To examine which baseline measurements constitute predictive factors for axial length growth over 2 years in children wearing orthokeratology contact lenses(OK) and single-vision spectacles(SV). Methods:This was a prospective non-randomized study. Eighty-four and eighty-two myopia patients(only took the right eye data) wore full correction single-vision spectacles(SV) and OK lens, respectively. Gender, age, age of myopia onset, myopia progression 2 years before baseline and baseline myopia and corneal astigmatism, corneal curvature, corneal thickness, anterior chamber depth, corneal diameter, pupil diameter, axial length(AL) at baseline and 2 years after wearing OK were collected. The baseline date of the two groups was matched. Univariate analysis and multivariate analysis were used to estimate the relationship between change in AL and baseline date of the two groups. Results:There were 73 cases(86.9%), 70 cases(85.4%) completed the follow-up in OK lens group and single-vision spectacles group, respectively. After univariate analysis, change in AL was associated with the following factors in the OK group. Change in AL was(0.34 ± 0.29) mm and(0.21 ± 0.31) mm(P <0.05) for male and female was respectively. The regression coefficient between age and change in AL was β=-0.066, R2=0.25,(P<0.001). The regression coefficient between age of myopia onset and change in AL was β=-0.073,R2=0.12, P=0.045 Change in AL was(0.14±0.12) mm and(0.15±0.13) mm in the first and second year for the OK group(P >0.05). Thirty cases were followed up three years and there were no significant statistically significant differences between three years. The regression coefficient between baseline myopia and change in AL, myopia progression 2 years before baseline and change in AL, pupil diameter and change in AL, ACD and change in AL, baseline AL and change in AL were β=0.052, R2=0.048(P<0.05), β=-1.02, R2=0.09(P=0.051), β=-0.06,R2=0.01(P<0.05), respectively. There was no correlation between change in AL and corneal astigmatism, corneal curvature, corneal thickness. After univariate analysis, change in AL was associated with the following factors in the frame glasses group. The regression coefficient between age and change in AL was β=-0.073, R2=0.37(P<0.001). The regression coefficient between age of myopia onset and change in AL was β=-0.082, R2=0.12(P=0.062). Change in AL was(0.31±0.19) mm and(0.30±0.18) mm in the first and second year(P>0.05). Twenty-eight cases were followed up three years and there were no significant statistically significant differences of AL growth for the three years. There was a descend trend for the growth of annual AL(P <0.05). The regression coefficient between corneal astigmatism, baseline AL and change in AL was β=0.45, R2=0.017(P<0.05), β=-0.07, R2=0.02(P<0.05), respectively. There was no correlation between change in AL and gender, baseline myopia, myopia progression 2 years before baseline, ACD, pupil diameter, corneal curvature, cornea thickness(P>0.05). After multivariate analysis, in the OK group, children of older age, higher myopia(Ptrend=0.046) at baseline exhibited smaller increases in axial length at 2 years. In the SV group, children of older age and larger cornea astigmatism exhibited smaller increases in axial length. Conclusions:OK lens was a successful treatment option in controlling axial elongation compared to SV in children of younger age, had earlier onset of myopia, were female, had bigger corneal astigmatism, had greater pupil diameter, had higher myopia at baseline, had quicker rate of myopia progression before baseline.regardless of the corneal curvature and corneal thickness. |
