13:01 The axis of the cylinder is mentioned to be 90° but the cylinder is drawn along 180°. This is an error as the correct orientation for the cylinder to be drawn is along 90° (axis of the cylinder) which would add the power at 180°.
I am confused about what the viedo say at 1:28. "the vertical image is actually being formed from horizontal meridian" but what the concept 1 shows while horizontl is focusing makes verital line Could you please explain that more details ? THX.
What a great lecture Ma’am , just one doubt , you gave an example of compound hypermtrophic astigmatism and from fogging we relaxed the accommodation and made the pt myopic , my question is if the pt is already a compound myopic will we still fog to bring the precise vision to 6/18? Also another question , how would we go about this test if it is simple myopic or simple hypermetropic astigmatism
This is refinement method. So first we want to give best corrected visual acuity by subjective refraction, then the patient VA- is 6/6 . Then we start fogging to make patient VA- 6/18(artifiicially compound myopic astigmatism) Then we will continue the procedure.
13:23 In this timestamp you give the example when the darker line is the horizontal line "3º - 9º" and multiply 3x30=90 and 90 degrees will be the axis for the correcting cylinder. This rule will also work when the darker line is the vertical line "6º - 12º" because 6x30=180 and 180 degrees will be the axis for the correcting cylinder. My question is when the darker line is the "1º - 7º" or is the "2º - 8º" or is the "4º - 10º" or is the "5º - 11º" then, for these lines, the rule of multiplying by 30 doesn't work. For example, if the darker line is the "2º - 8º" and multiply 2x30=60 then 60 degrees would be the axis for the correcting cylinder, but in reality, the axis for the correcting cylinder must be 120 degrees. The same error happens when you use the other lines ("1º - 7º", "4º - 10º", "5º - 11º"). Can you explain this, or correct me if I am wrong? Thank you in advance.
Actually the concept works..instead of sunburst type of dial try on clock type..such that 3 clock hr represent 0 degrees, 4th clock hr 30 degree ....8th 150, 9th 180..I don't know if it's correct but I just tried & it worked.
You are right! It doesn't work as such for all the clock hours. Instead, you can remember that the axis is 90° for 3-9 o'clock and then work around from there. For every 1 clock hour clockwise, subtract 30° degrees from 90°. For every 1 clock hour anticlockwise, add 30° to 90°. Example: For 2-8 o'clock sharp line, axis would be 90°+ 30° = 120°. For 5-11 o'clock sharp line, axis would be 90° - 2*30° = 30°
I have a doubt plz clarify mam in @10.09min, after getting best Vision sph with improvement of 6/9 , do I need add more power to get 6/6 va before performing fogging?
If I understood your question correctly, I think you are asking about achieving the BCVA before fogging? So yes you try to get that first .However if there is some pathology, some patients will not be able to achieve 6/6 .For them 6/9 is the BCVA. To detect such cases, at 6/9 try adding/ subtracting ( continue refraction ) to try achieve 6/6 ...then go ahead and do fogging to relax accomodation If your patient can't see 6/6 still...you can fog even with 6/9 as initial point and fog the patient by 3 lines
If i se vertical lines clearly becouse of the overlaping...what degreas shuld i have on my glasses? 180 degrees? I see ghosting images of the objects even with my astigmatism glasse...
13:00 Axis of the cylinder is along the length of the Cylinder.... But, u have mentioned it wrong here ( This part is very confusing that WHY we've to put the axis in 90° from clear line)
because we have to move the vertical image to the horizontal image and for us to do that, we have to put 90 degrees axis because it is equal to 180 meridian which is in control of the vertical image
13:01 The axis of the cylinder is mentioned to be 90° but the cylinder is drawn along 180°. This is an error as the correct orientation for the cylinder to be drawn is along 90° (axis of the cylinder) which would add the power at 180°.
6:14 is confusing you said that horizontal meridian make vertical image but in this you chose horizontal image make horizontal meridian can't get make it clear🙏
Kindly rewatch the video.. Horizontal meridian forms a vertical image and vice versa. At this time stamp I am trying to explain which image is darker... And that retrospectively would be coming from the vertical meridian
Plz mam clear my confusion that why horizontal meridian make vertical line and vertical meridian make it horizontal line(image).... Will be much thankful for this clarification @@InsightOphthalmology
Plz mam clear my confusion that why horizontal meridian make vertical line and vertical meridian make it horizontal line(image).... Will be much thankful for this clarification @@InsightOphthalmology
