The Design And Application Of New Near Log Acuity Chart

Objective:To develop a kind of new near logarithms visual acuity chart that is suitable for china reality and ophthalmology clinic to use of.Develop with the far visual acuity chart already gradually perfect,but develop with the near visual acuity chart is empty to some extent.As the coming of aging society,the near work need of the elderly is increasing.In the meantime,enter higher school and employment pressure were more and more increased,make child and teenager the opportunity of near use eyes increasingly,but also increase near use the need of visual acuity exam.Especially the low vision patients occupies considerable proportion our country,judged with accuracy in early days whether is a low vision,gave them a aids treatment early,can raise the living quality of low vision patients effectively. Therefore,we developed a kind of the tool of near visual acuity exam-《New Near Logarithms Visual Acuity Chart》.Contents:Collect,tidy up,analyzed various visual acuity chart for far and near at home and abroad with nearly 20 species,develop a kind of the tool of near visual acuity exam-《New Near Logarithms Visual Acuity Chart》.Method:《New Near Logarithms Visual Acuity Chart》was designed according to the country(GB-11533-89)design,but also obey Weber-Fechne rule strictly,then see object each row or indentation widths are 1' angle of views,and the principle homology of "standard logarithms visual acuity chart" of current expansion,but again have special.A total of 59 patients(118 eyes)with no eye diseases(except cataract and refractive error)were taken at random from eye center.All the cases were divided into three groups according to ages:0～18 years old group,19～45 years old group,＞45 years old group.At the same time,the cases were measured respectively by four kinds of visual acuity charts:《Standard Near Visual Acuity Chart》《Logarithms Near Visual Acuity Chart》《log MAR Near Visual Acuity Chart》with lately- developed《New Near Logarithms Visual Acuity Chart》.And then,naked vision and corrective vision were record,carry on a F test analysis.Result:Naked visual acuity:3 groups all have no obvious difference.Corrected visual acuity:＞45 years old group has no obvious difference,0～18,19～45 years old group four kinds of visual acuity charts contain difference p＜0.05.Among them,the visual acuity result of《New Near Logarithms Visual Acuity Chart》is lower 0.09 than《Standard Near Visual Acuity Chart》,namely the visual acuity discrepancy near 1 line to see a mark;Lower 0.05 than《Logarithms Near Visual Acuity Chart》, namely the sight discrepancy near a half line to see a mark;visual acuity exam result of《New Near Logarithms Visual Acuity Chart》is same with《log MAR Near Visual Acuity Chart》.Conclusion:Old-age group:four kinds of visual acuity charts make no difference degree,and the difference of the visual acuity may be caused by decrease of contrast sensitivity degree and anatomical structure and physiological function.0～18, 19～45 years old group:four kinds of visual acuity charts contain difference.It is analysed that there are different and similar in design principle,design form,visual acuity record method and changing distance etc,among various visual acuity chart. Was experimented by clinical contrast,four kinds of visual acuity charts all can be a general eye exam usage,but check sight for the special patient,such as old man, child,low vision patient etc,recommend《New Near Logarithms Visual Acuity Chart》is more science,accurate.《New Near Logarithms Visual Acuity Chart》filled with visual exam on the domestic gap,is China's logMAR,the visual chart has awarded China's patents, patent NO:ZL200630024136.5,2006.