title: [The long-term clinical effects of orthokeratology in high myopia children].
abstract: OBJECTIVE
  To investigate the long-term clinical effects of orthokeratology (ortho-k) in high myopia children with 5 years of follow-ups.
  
  
  METHODS
  Prospective study. We chose 30 high myopia patients to wear ortho-k contact lenses (CLs) for controlling or delaying myopia progression from 2003. Among them, there were 10 boys and 20 girls whose average age was (15 ± 2) years, spherical diopters were (-7.34 ± 0.91) D, corneal astigmatism diopters were (-1.06 ± 0.62) D, uncorrected visual acuity was LogMAR 0.89 ± 0.29, corneal flattened curvature was (43.54 ± 1.16) D, and axial length was (26.38 ± 0.94) mm. All patients, with informed consent before fitting of ortho-k CLs, had conventional refraction and ocular tests. We compared the values of spherical diopters, visual acuity, corneal flattened curvature and axial length before and 6 months, 1 year, 2 years, 3 years, 4 years and 5 years after wearing CLs, respectively. The results were analyzed by SPSS 16.0 software.
  
  
  RESULTS
  During the five years of observation periods, all patients' visual acuity and corneal flattened curvature were different from the pre-fitting (P < 0.05). Compared to the pre-fitting, the naked visual acuity was some degree improved, it was LogMAR 0.45 ± 0.31, 0.49 ± 0.32, 0.43 ± 0.30, 0.47 ± 0.31, 0.58 ± 0.35, 0.53 ± 0.27, respectively. F = 10.725, P = 0.000. Corneal flatten curvature was tend to be flatter, such was 41.14 ± 1.54, 41.75 ± 1.88, 41.54 ± 2.10, 41.73 ± 1.89, 41.94 ± 1.61, 40.70 ± 1.67. F = 10.161, P = 0.000 (All P < 0.05). The spherical diopters during the first two years after wearing ortho-k CLs were significantly reduced, compared with the previous values (it was -5.23 ± 1.81, -5.59 ± 2.75, -6.29 ± 2.12, -6.63 ± 2.31, -6.83 ± 2.33, -7.01 ± 1.81, respectively, F = 4.929, P = 0.000), and kept stable in the long-term observation. The axial length checked at 5 years was slightly elongated (it was 26.41 ± 0.90, 26.68 ± 0.93, 26.69 ± 1.06, 26.75 ± 0.94, 26.81 ± 1.04, 27.04 ± 1.01. F = 1.831, P = 0.094). The axial elongation was retarded by using ortho-k CLs in high myopia children. All patients were not subjected to severe complications which may lead to quitting the enrollments.
  
  
  CONCLUSIONS
  Orthokeratology used in controlling or delaying high myopia progression is definitely outstanding in 5 years observations. Standard lens wearing and regular lens check improve safety of lens use in high myopia.
authors: Beijing Bei Yi Optometry & Ophthalmology Center, Beijing 100027, China.
authors: Jianlan
authors: J
authors: Zhou
authors: Beijing Bei Yi Optometry & Ophthalmology Center, Beijing 100027, China; Email: xpy@b-d.ac.cn.
authors: Peiying
authors: P
authors: Xie
authors: Beijing Bei Yi Optometry & Ophthalmology Center, Beijing 100027, China.
authors: Dan
authors: D
authors: Wang
authors: Beijing Bei Yi Optometry & Ophthalmology Center, Beijing 100027, China.
authors: Xi
authors: X
authors: Guo
authors: Beijing Bei Yi Optometry & Ophthalmology Center, Beijing 100027, China.
authors: Lina
authors: L
authors: Yang
mesh_terms: D000293:Adolescent; D001251:Astigmatism / Q000175:diagnosis; D002648:Child; D003261:Contact Lenses; D019781:Corneal Topography; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D009216:Myopia / Q000517:prevention & control*; D011446:Prospective Studies; D055502:Secondary Prevention / Q000379:methods; D014787:Vision Tests; D014792:Visual Acuity