اختبار ثنائي اللون انكسار ذاتي أحادي العين نقطة نهاية الانكسار الكروي

hello Eyecare practitioners welcome to Optometry rails have you ever come across situation when your patient has two different glasses and the visual Equity with each of this glass is six by six or 20 by 20 then how do you decide that which among these two is more accurate for your patients you might have also seen situation where Auto refractometer is giving one value and patient is accepting something else sometimes patient is even confused between the two different prescription then how do you ensure that which among these two is more accurate how do you make sure that your prescription is not under corrected or over corrected so well to decode this all mystery we are going to make you learn you from test this test is used for the monocular subjective refraction which can be done monocularly as well as binocularly so please be present with us till the end to learn every minute details of this new Chrome test Chrome chart which uses distance activity chart with the black letter or symbols on green and red background this test is also known as by Chrome test which is usually done for the distance friends have doubt since red green filters are used in this test will this still be applicable for the colored efficientation this test is based on eggshell or longitudinal chromatic aberration not on the color discrimination hence this test can even move the home on the color diffusion patient as we all know the light consists of seven different colors so the shorter wavelength of light which is green is refracted more by the eye then the longer wavelength of light which is red in in metropica the latest on both background of Duke from chart are equally clear as Optics of the eye refract Rays at equidistance from the retina to maintain the circle of less confusion and this is what we aim even for the myopic and hyperopic eye with full correction if your patient says that later on green background is better it means that you have under corrected hyperopia or over corrected myopia when your patient says that later on the red background is better then it shows that hyperopia is over corrected or if it's myo then it is under corrected and many literature support that my player should be under corrected and hyperopia should be over corrected so it means minimum minus for the myopia and maximum Plus for the hyperopia should be given as per recent literatures the latest on the red green background of the DU Chrome should be equally clear and sharp to have the optimum refract this test can be performed at two different points during reflection one after base Vision sphere before JCC or even you can perform after JC to finalize your refraction the prerequisites for Duke room test is the new Chrome chart you need to have trial frame and the trial lenses and the room has to be deluminated let me show you how do Chrome can be done on actual patients so minus 1 we have got on the fogging and even the same was for the auto refractometer so I'm going to put this in trial frame and since this test is monocular so have to occlude an eye and have to ask the response so make sure that you should be asking the latest on which background is sharp and clear can you sing so green is better it suggests that in myopia it is over corrected so have to reduce this value so from minus 1 am going to make it 0.75 by adding plus 0.25 now and is both equal sharp and clear so let us on both background are equally sharp and clear it means we have achieved the optimum correction so I'll change it again to minus 0.75 with one lens and as the response so hence this is the actual value that we require to prescribe her for the right type from minus 1 we got 0.75 so it means that earlier description was over corrected so new Chrome test help us refine our spherical values so it gives us spherical endpoint so if we want to make sure that your refraction is neither over corrected or under corrected you should perform due Chrome test for all your patients hope this video was clear and informative to you please like and share the video and subscribe