Based on the analysis of the theoretical calculation model of axial resolution of optical coherence tomograph for the posterior segment of the human eye, a set of testing device for measuring its axial resolution is designed and developed. In view of a commercial ophthalmic optical coherence tomograph in clinical use, its axial resolution is calculated to be 5.07 μm theoretically, and the actual measurement value is 5.45 μm. The uncertainty of the detection device is evaluated and the result is (5.45±0.10) μm. The measurement error introduced by the testing device is very small. Meanwhile, the axial resolution measured by the testing device meets the requirements of the instrument(≤ 6 μm).
Algorithms ; Eye ; diagnostic imaging ; Humans ; Tomography, Optical Coherence ; Uncertainty

Objective To investigate high risk human papillomavirus(HR-HPV)prevalence among married women in Beijing and to study the high risk flactors.nethods During March 2007 to September 2008.a total of 6185 married women sampled from 137 communities in 12 districts were screened bv HR-HPV DNA test and cytogical test.The interview was carried out with unified questionnaires.The databage was set up and twice entered in EpiDam 3.0.After checked up,the data were analyzed in SPSS 15.0.Results (1) The HR-HPV infection rate was 9.89%.The HR-HPV infection rate of the city zone,the suburb and the exurb were 9.34%,10.51% and 9.51% (P>0.05).The HR-HPV infection rate of the native and the oudander were 9.53%,11.30% (P<0.05).(2) The age distribution of HR-HPV infection was that the rate was around 10% among 25 to 44 age groups,which was the highest(11.21%) in 30 to 34 age group;then the rate was descended as the age raising,the rate of 50 to 54 age group was the lowest(7.78%).(3) Multiple logistic regression showed that the related risk factors of HR-HPV infection mainly included 1000 RMB and above of family income per person per month.possessing more than 1 sexual partner of her husband,outlander and hish levels of education.(4) The prevalence of cervical intraepithelial neoplasia(CIN)in HR-HPV positive group wag significantly higher than that in HR-HPV negative group(29.76% vs 3.32%,P<0.01).Conclusions(1)The HR-HPV infection rate among aged 25 to 54 years was 9.9% and there was no significant difference in area distribution.(2)The hish risk population which should strengthen screening was the married bearing-age women with high level of family income,outlander,high levels of education and her husband possessing more than 1 sexual partner.(3)HR-HPV infection is the main risk factor for CIN and cervical cancer.while does not provide a causal relationship with them.The high risk population should be checked regularly to understand the development of HR-HPV infection and CIN incidence.