title: Comprehensive Evaluation of Anterior Corneal Change in Asphericity Calculated by the Tangential Radius of Curvature after LASIK.
abstract: To evaluate the change in the anterior corneal asphericity (ΔQ) comprehensively calculated using the tangential radius (rt) after LASIK. Forty-two right eyes were evaluated using the Orbscan II corneal topographer. The pre- and postoperativeQ-values of the flat principal semimeridians calculated by the sagittal radius were compared to those by the tangential radius. TheQ-value of each semimeridian in the horizontal region was calculated byrt. Fourier fitting was used to model the 360-semimeridional variation ofQ-values and to fit theQ-values in the vertical region before and after surgery. There were significant differences inQ-values between the two methods before (P< 0.001) and after surgery (P= 0.003). A significant increase in postoperativeQ-value was detected compared to preoperativeQ-value (P< 0.001) calculated byrt. The 360-semimeridional variation of theQ-values was well fitted with a third- and fourth-degree Fourier function before and after surgery. The ΔQ-value distribution presented double valley variation, with the amount of ΔQbeing lowest in the near-vertical regions and highest in the near-horizontal regions. Calculating theQ-value withrtcombined with Fourier fitting, we evaluated 360 ΔQ-values' variation of semimeridians of the entire anterior corneal surface and then displayed true and complete anterior corneal shape after LASIK.
authors.affiliation: Department of Ophthalmology, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, 3 East Qingchun Road, Hangzhou 310016, China.
authors.forename: Jinglu
authors.initials: J
authors.lastname: Ying
authors.affiliation: Department of Ophthalmology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, No. 109, West-Xueyuan Road, Wenzhou 325027, China.
authors.forename: Jianqiu
authors.initials: J
authors.lastname: Cai
authors.affiliation: Department of Ophthalmology, The First Affiliated Hospital of Wenzhou Medical University, No. 2, Fuxue Lane, Wenzhou 325000, China.
authors.forename: Leru
authors.initials: L
authors.lastname: Zhu
authors.affiliation: Department of Ophthalmology, The Second Affiliated Hospital and Yuying Children's Hospital of Wenzhou Medical University, No. 109, West-Xueyuan Road, Wenzhou 325027, China.
authors.forename: Yi
authors.identifier: 0000-0002-2565-9528
authors.initials: Y
authors.lastname: Zha