Experimental Sciences
Change of the focused depth of biconvex Toric intraocular lens in Hwey-Lan Liou schematic eye
Xin Yang, Bin Zhang, Danyan Liu, Yinghua Du, Congrong Guo, Yuexian Cui
Published 2015-04-10
Cite as Chin J Exp Ophthalmol, 2015, 33(4): 347-350. DOI: 10.3760/cma.j.issn.2095-0160.2015.04.012
Abstract
BackgroundToric intraocular lens (IOL) has two optical powers in two perpendicular directions, and it could result in many different optic performance from spherical IOL.
ObjectiveThis study was to evaluate the depths of focus of spherical, aspherical and Toric IOL under polychoromatic light by Hwey-Lan Liou schematic eye.
MethodsHwey-Lan Liou schematic eye was created using Zemax software, and the alterations of focusing depth of Tecnis ZA9003 IOL (a spherical IOL), SN60AT IOL(a aspherical IOL), Arcysof Toric IOL were evaluated and compared based on Hwey-Lan Liou schematic eye by ray tracing method.
ResultsThe modulation transfer function (MTF) was perfect and the depth of defocus was equal under the zero defocus and under the pupil diameter of 3 mm with symmetrical focus curve in plus or minus two-axis in both spherical IOL and Toric IOL. The MTF decreasing with 5 mm pupil compared with that with 3 mm pupil. The MTF was declined under the pupil diameter of 5 mm compared with 3 mm in spherical IOL and Toric IOL along with the decrease of focus depth and the drifting of MTF toward negative axis. However, only the focus depth was decreased but MTF appeared to be stable in aspherical IOL.
ConclusionsToric IOL and spherical IOL exhibit similar trends in focus depth change, and their focus depths decrease with the increase of pupil diameter. In addition, Toric IOL and spherical IOL show good light focus during minus defocus shifting.
Key words:
Lenses, intraocular; Astigmatism; Eye, artificial; Focused depth
Contributor Information
Xin Yang
Department of Ophthalmology, Second Hospital of Hebei Medical University, Shijiazhuang 050000, China
Bin Zhang
Danyan Liu
Yinghua Du
Congrong Guo
Yuexian Cui
