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Analysis of the optical quality by determining the modulation transfer function for anterior corneal surface in myopes

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International Journal of Ophthalmology(English edition) 2012年第2期5卷 196-201页

作者： Yan-Zhen Zheng, Yao-Yu Li Department of Ophthalmology General Hospital of Beijing Military Command of Chinese PLA Beijing 100700 China Shanxi Medical University Taiyuan 030001 Shanxi Province China

AIM: To describe the characteristics of modulation transfer function (MTF) of anterior corneal surface, and obtain the the normal reference range of MTF at different spatial frequencies and optical zones of the anterior corneal surface in myopes. METHODS: Four hundred eyes from 200 patients were examined under SIRIUS corneal topography system. Phoenis analysis software was applied to simulate the MTF curves of anterior corneal surface at vertical and horizontal meridians at the 3, 4, 5, 6, 7mm optical zones of cornea. The MTF values at spatial frequencies of 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55 and 60 cycles/degree (c/d) were selected. RESULTS: The MTF curve of anterior corneal surface decreased rapidly from low to intermediate frequency (0-15cpd) at various optical zones of cornea, the value decreased to 0 slowly at higher frequency (>15cpd). With the increase of the optical zones of cornea, MTF curve decreased gradually. 3) In the range of 3 mm- 6 mm optical zones of the cornea, the MTF values measured at horizontal meridian were greater than the corresponding values at horizontal meridian of each spatial frequency, the difference was statistically significant (P<0.05). At 7 mm optical zones of cornea, the MTF values measured at horizontal meridian were less than the corresponding values at vertical meridian at 10-60 spatial frequencies (cpd), and the difference was statistically significant in 25, 30, 35, 40, 45, 50 cpd(P<0.05). CONCLUSION: MTF can be used to describe the imaging quality of optical systems at anterior corneal surface objectively in detail.

关键词： modulation transfer function optical quality cornea point spread function optical transfer function phase transfer function

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phase Difference function in Coherent Temporal-spatial Region and Unified Equations of Steady, Non-steady Interference

Phase Difference Function in Coherent Temporal-spatial Regio...

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中国光学学会2004年学术大会

作者： Ji Luo1,2 (1 Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100039 China) (2 Department of Physics, Dalian University, Dalian, 116622 China)

A phase difference function within the interference temporal-spatial region is obtained by a subtraction with two phase transfer functions, each of which transfers a corresponding phase between time d

关键词： phase transfer function coherent wave information information modulation phase difference function steady and non-steady interference equation beat frequency and interferometry.

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