Effect of overnight orthokeratology on corneal topography and tears / 国际眼科杂志(Guoji Yanke Zazhi)

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.