Ophthalmology in China ›› 2012, Vol. 21 ›› Issue (6): 376-380.

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The short-term effects of orthokeratologic lens on central and peripheral corneal thickness

 DI  Zhou,   Yang-Xiao,   Wang-Hua-Rong,   Fang-Bing-Lan,   Dai-Zu-You,   Wei-Ling   

  1. Zhongshan Ophthalmic Center of Zhongshan University, Ophthalmology State Key Laboratory, Guangzhou 510060, China
  • Received:2012-10-07 Online:2012-11-25 Published:2012-11-26
  • Contact: YANG Xiao, Email: yangxiao3366@gmail.com

Abstract: 【Abstract】 Objective To observe the short-term changes of the central and peripheral corneal thickness after wearing orthokeratology (OK) contact lenses overnight. Design Prospective case series. Participants 103 patients (197 eyes) with myopia, average ages 19.0±7.5 years, average spherical equivalent refraction-3.25±0.91 diopters (D). Methods All the patients wore orthokeratology lens overnight. The corneal thickness was measured with a rotating Scheimpflug camera (Pentacam) on different corneal areas, including central, peripheral corneal ring on radius 1 mm, 2 mm, 3 mm and 4 mm. The changes of spherical equivalent refraction and central corneal radius of corneal topography were measured also. All the examinations were done on baseline and 1 day, 1 month, 3 months after wearing OK. Main Outcome Measures Corneal thickness (CT), spherical equivalent refraction (SER), central corneal radius (CCR). Results Compared with baseline, SER reduced -3.01±0.09 D in 3 months and CCR reduced 2.40±0.15 D (both P<0.05). After 1 night wearing, compared with pre-wearing CT increased 5.90± 3.69 μm, 7.54±3.73 μm, 10.52±3.91 μm, 11.76±4.23 μm, 9.33±4.93 μm from the center, to radius 1 mm , 2 mm, 3 mm and 4 mm respectively (all P<0.05).  After 1 month, CT reduced -4.18±3.68 μm and -0.50±3.73 μm in the center and radius 1 mm respectively, but increased 6.39±3.91 μm,9.57±4.22 μm,2.00±5.05 μm in radius 2 mm, 3 mm, 4 mm, respectively. After 3 months, CT reduced -6.61±3.67 μm and -3.67± 3.72 μm in the center and radius 1 mm respectively. But CT increased 3.05±3.90 μm, 6.42±4.21 μm, 5.63±4.94 μm in  radius 2 mm, 3 mm, 4 mm, respectively (all P<0.05). The central corneal thickness changed faster than peripheral corneal thickness in different time (P=0.00). Conclusion The changes of corneal thickness after wearing orthokeratology lenses are consistent with the changes of the shape of cornea. The central cornea becomes thin and the cornea from radius 2 mm to peripheral becomes thick. (Ophthalmol CHN, 2012, 21: 376-380)

Key words: myopia, orthokeratology, corneal thickness