ABSTRACT
Objective To evaluate of the effect and safety of wearing orthokeratology contact lens or frame glasses for controlling myopia in children. Methods The clinical data from myopia children, who wore orthokeratology contact lens or frame glasses to control myopia, were analyzed retrospectively. Of 219 children (396 eyes), 145 children (277 eyes) wore orthokeratology contact lens, and 74 (119) frame glasses. The changes of diopter, axial length and corneal endothelial cells were observed and compared one year after treatment in the two groups. Results After wearing one year, the diopter and the variation of diopter were significantly less in the children wearing orthokeratology contact lens than those in the children wearing frame glasses ([-3.03±0.89] DS vs [-3.83±1.25] DS, [-0.84±0.90] DS vs [-1.83±0.71] DS; both P<0.05). There was no significant difference in the axial length between the children wearing orthokeratology contact lens and frame glasses. While the extension of axial length was significantly less in the children wearing orthokeratology contact lens than that in the children wearing frame glasses ([0.14±0.15] mm vs [0.40±0.17] mm, P<0.05). No significant differences in the area or density of corneal endothelial cells were found between the children wearing orthokeratology contact lens and frame glasses. Conclusion Wearing orthokeratology contact lens can effectively control myopia in children within one year, and it had no adverse effects on corneal function.
ABSTRACT
To study the effect of wearing overnight orthokeratology ( OK) contact lens on corneal topography and tears in adolescents.METHODS: The diopter, corneal curvature, corneal surface regularity index ( SRl ) , tear break - up time ( BUT ) , Schirmer l test, and corneal fluorescent ( FL ) were recordedon 40 (80 eyes) adolescent myopia patients (mean age 13. 68±2. 32 years), who had worn OK contact lensfor more than 1 year, with mean spherical equivalent refraction -3. 61 ± 1. 48D before wearing OK contact lens. These indexes were tested and recorded before the patients' wearing OK contact lens and 5 times (1wk and 1, 3, 6, 12mo after the first wearing) during the patients' overnight wearing OK contact lens for 8~10 hours per day.RESULTS: Compared with pre - wearing, at post -wearing OK contact lens 12mo, the mean spherical equivalent refraction was apparently decreased from -3.61±1. 48D to -1. 39±1. 31D(P 0. 05 ). There were no significant differences on Schirmer▏test during the 12mo of OK wearing(P>0. 05). The cases of corneal fluorescent staining increased were mainly grade l, and the number of corneal staining grade l at 1 wk and 1, 3, 6, 12 mo after wearing were 15 eyes (18. 8%), 9 eyes (11. 3%),13 eyes (16. 3%), 9 eyes (11. 3%), and 12 eyes (15. 0%). BUT of corneal staining grade l wasdecreased significantly, compared with the BUT of corneal staining grade 0 during the 12mo of OK wearing (P<0. 05). CONCLUSlON: OK contact lens can significantly decrease the degree of myopia and K value of corneal curvature without changing tear volume. However, tear film stability weakens, which needs regular follow-up.
ABSTRACT
Background Wearing of orthokeratology contact lens can slow down the development of myopia,especially in childhood.However,if wearing orthokeratology contact lens for long-term affect the corneal health is worthy of consideration.Objective This study was to evaluate the security of wearing orthokeratology contact lens in children.Methods A retrospective case-observational study was adopted.One hundred and fifty eyes of 76 myopic children aged 8-15 years were enrolled in Shanghai Tenth People's Hospital during December,2009 to December,2011.Orthokeratology contact lens were worn at night for 8-10 hours daily.Area of corneal endothelial cells,density of corneal endothelial cells,coefficient of variation of corneal endothelial cells and percentage of hexagonal cells were measured before wearing and 3,6,12,24 months after wearing.Repeated measurement of single factor analysis of variance was used to evaluate the changes of corneal endothelial cells after wearing of orthokeratology contact lens.Results No significant differences were found in the area of corneal endothelial cells and density of corneal endothelial cells among the different time points (F =11.34,P＞0.05 ; F =7.16,P＞0.05).A significant difference was seen in the coefficient of variation of corneal endothelial cells at various time points in the children(F=12.70,P=0.02),and the coefficient of variation of corneal endothelial cells was 0.36±0.02 24 months after wearing lens,which was higher than 0.28 ±0.05 before wearing lens (P＜0.05).In addition,the percentage of hexagonal cells in different time points was significantly different (F=13.40,P =0.04),and the percentages of hexagonal cells at 12 hours and 24 months after wearing lens were (62±12)％ and (60±14)％ respectively,which was significantly lower than (69±12)％ before wearing lens (P＜0.05).Conclusions Wearing of orthokeratology contact lens for over one year leads to the decrease of percentage of hexagonal cells and increase of coefficient of variation of corneal endothelial cells.