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Evaluation of Myopic Progression in Orthokeratologic therapy for

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					  Evaluation of Myopic Progression in Orthokeratologic therapy for students in Taiwan
William Cheng , Cheng’s Eyes Clinic
Purpose:
    The mainly purpose of orthokeratologic therapy is blockage of myopic progression , not to correct the
myopia.
Method:
      There are 557patients (1059eyes),from1998 Feb.14 to 2004 Feb.13, received with orthokeratologic therapy
for the rapidly progression of myopia in our ophthalmic departments. They were followed up in my clinic every
week in the first 3 mouths period and every mouth in later, and checked up the naked and corrected visual
acuity, cornea and the external ocular surface by slit-lamp every clinic time. However, they should be checked
up the lens wearing pattern about the centering, central curve , compression area , lens movement and tear
content under the fluorescent stain every time.
     Lens Design:The design of orthokeratologic (ok)lens were according double reverse geographic theory with
4 curves as fellows: Basal Curve 6.0 mm, Fitting Curve 0.6mm, Alignment Curve 1.1mm and Peripheral Curve
0.4mm.Thediameter of lens were 10.2mm. The central thickness of ok lens were 0.2mm.The lens material is
BonstonXO (KD value ,110) proved by FDA.
     Cleaning Method: Using daily cleaning solution and conditional solution for permeable gas hard contact
lens but paying more attention to the cutting angle between basal curve and fitting curve
     Overnight wearing about 6~8 hours for all patients excluding the daily wearing cases, Alarm system being
set up for preventing infection as fellows: (1) Stopping the ok. lens wearing if ocular pain persisting for 2 hours,
(2) Visiting the eye’s clinic if the ocular pain persisting for 6 hours, (3) Wearing withdraw one day per week
(weekend).
     Evaluation of the refractional change after stopping orthokeratologic therapy from 1to 6 mouths (average
2.4 mouths) in 20 students amount of 557 patients with orthokeratologic treatment over half year to 6.25
years(average2.63years)
Result:
    Compare with the original myopic state of this 20 cases (average treatment for 2.63 years) , there was no
any myopic progression ( 47.10 degrees below the original data) for them with orthokeratologic
therapy( average stopping therapy for 2.4 mouths.) , as the table 1.and Fig 1,
Discussion:
     Compared with the other myopic corrections, orthokeratologic myopic therapy with a better prognosis
for myopic progression.
     Compared with cycloplegic drug therapy for the school students (from 7 to 18 years olds), We had better
dates in ok therapy for the blockage of myopic progression, as the table 1.and Fig 1.Cycloplegic drug only
slowing the progression of myopia but couldn’t stopped it.
     Although glass wearing providing the best corrected visual acuity, it couldn’t prevent the myopia
progression
      The soft contact lens providing the functions as same as glass, but the hard contact lens also performed a
role for myopia progression. The OK lens ,also a extended permeable hard lens , performing a important role
for the student myopia progression during learning stage, might be a good choice for students or their parents
worried their myopia progression , especially malignant myopia.
Conclusion:
    There was no any myopic progression ( 47.10 degrees below the original data) for the students with
orthokeratologic therapy ( average stopping therapy for 2.4 mouths.) , compared with the average 75 degree
increase myopic change per year of the recent epidermiologic data in Taiwan.(Table 2 and Fig.2)
Fig.1
   Compare with the original myopic state of this 20 cases (average treatment for 2.63 years) , there was no
obvious myopic progression ( average 47.10 degrees below the original data) for them with orthokeratologic
therapy ( average stopping therapy for 2.4 mouths.)


                                     接受角膜塑型片之停戴時況分佈圖
         200
         150
         100
          50
   增
   減     0
   度 - 50 0                     1                 2                 3                4                 5           6   7
   數 - 100
       - 150
       - 200
       - 250
       - 300
       - 350
                                                                  停戴時間( 月)

Stopping ok lens therapy(mouths)


     年別              72 年           75 年           79 年           84 年           89 年            92 年
國小一年級                     5.8%           3.0%           6.5%         12.8%          20.4%           24.7%
國小六年級                   36.7%          27.5%          35.2%          55.8%          60.5%           48.7%
國中三年級                   64.2%          61.6%          74.0%          76.4%          80.7%           71.3%
高中三年級                   76.8%          76.3%          75.2%          84.1%          84.2%           86.0%

                                                                                                                       72年
                                           台灣地區學生近視盛行率統計圖
                                                                                                                       75年
        100%                                                                                                           79年
                                                                                                               86.0%   84年
         80%
                                                                                                                       89年
    盛 60%                                                                                                              92年
    行
    率 40%
         20%
                                 24.7%

           0%
                        國小一年級                         國小六年級                    國中三年級                       高中三年級

                                                                     年別

				
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posted:6/22/2011
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