Analysis Of Influencing Factors To The Contrast Sensitivity

On the subject, we mainly analyze the impact of spatial frequency,age, refractive error, brightness and glare on contrast sensitivity, including all the factors basically which have a major impact on the contrast sensitivity.ObjectiveTo discuss the impact of the age,luminance,glare,spatial frequency and refractive error on the contrast sensitivity.Methods(1) According to the standard procedures,subjective and objective refraction examination were carried on.(2) Correcting the myopia with frame eyeglass completely,requiring the corrected visual acuity is 1.0 or above.All the myopia patients must be examined by slit lamp microscope and ophthalmoscope,to make sure that all the patients have no other ocular diseases.For all the patients of high myopia,we order all the paticnces have no eye Pathological changes caused by the high myopia.(3) The patients were examined by OPTEC6500 visual function instrument under four simulated conditions (85cd/m2 without glare,85cd/m2 with glare,3cd/m2 without glare,3cd/m2 with glare)(4) The data was analyzed by the Wilcoxon rank sum test using SPSS 11.5.Results(1) Glare:In the bright (85cd/m2) and lightless (3cd/m2) surrounding,statistically significient differences (P<0.05) were found when the patients discriminate things with low and middle spatial frequencies (1.5c/d,3.0c/d,6.0c/d).(2) Luminance:There were statistically significient differences (P<0.05) between 85cd/m2 and 3cd/m2,when you discriminate things with middle and high spatial frequency (6.0c/d,12.0c/d,18.0c/d)(3) Spatial frequency:For all the myopia patients with different degrees, the statistically significient differences caused by different spatial frequencies were found in all conditions (85cd/m2 without glare,85cd/m2 with glare,3cd/m2 without glare, 3cd/m2 with glare).(4) Refractive error:Different refractive error can cause statistically significient differences (P<0.05) under these circumstances (differentiating the target with 12.0c/d under the circumstance of 85cd/m2 without glare,distinguishing the target with 6.0c/d under the circumstance of 3cd/m2 without glare and dividing things with 12.0c/d 18.0c/d and under the circumstance of 3cd/m2 with glare).(5) Age:statistically significient differences (P<0.05) were found between different patients with different ages (11-20 years old,21-30 years old,31-40 years old,41-50 years old).ConclusionAge,luminance,glare,spatial frequency and refractive error can influence the contrast sensitivity in different degree in various conditions.(1) Glare could influences the contrast sensitivity more completely.(2) In the surroundings of 85cd/m2 and 3cd/m2,the ability of discriminating low spatial frequency is same,while the ability of discriminating middle and high spatial frequency is different.(3) In the light surrounding (85cd/m2),the CS value is biggest when human eyes ovserve the target with 6.Oc/d.While in the dark environment (3cd/m2),human eye's favourate spatial frequency is 3.0 c/d.We conclude that,the the peak of contrast sensitivity appears in the low spatial frequency zone.(4) In the condition of 85cd/m2 without glare,the contrast sensitivity discend,when the high mypoia patience discriminate the things with 12.0c/d;In the circumstance of 85cd/m2 with glare,the ability of discriminating is same in all the myipia patiences; the ability of low myopia is strongest in the darkness.(5) CS has a falling trend according to the increasing of age. This shows that, in the light environment, the human eye with 11-20 years old distinguish the best.