Cross Cyl Refraction Part 2: Subjective Refraction Part 8

[@Lasikdrlookgade]

I​ wish​ I​ watched your​ tutorials​ during​ residency.​ The​ simplest yet​ productive​ way​ to​ learn refraction!

[@spriggiehensley3770]

It should be explain that - Once the axis is found, next is the power of the cylindrical correction is determined. This power finding step will indicate whether a minus or positive cylinder is required to correct the astigmatism. It took me a minute to figure out when to use the minus or plus cylinder from my trial kit, Copilot saved me!

[@jonkrahmer3987]

Ian, thank you for the trial lens and frame youtube video!!!

[@manaspradhan9271]

SIR I AM FROM INDIA AND I FOLLOW YOUR ALL VIDEO SIR I GLAD TO SAY THAT ALL OF YOUR VIDEO GREAT ........... GREAT HELP FOR ME

[@nirmaljayadev]

That's a really good video demonstration on Jackson's cross cylinder Ian.. Am an Ophthalmology Post graduate student from India. Found your videos extremely informative. Will come up with doubts shortly.. :-)

[@CharlieKaneSeattle]

There's a mistake at 8:40 step 4.... regarding cylinder. Just a heads up. Thanks for the great information. Really helpful.

[@sarafinadaniel5710]

I watch this to lean the cross cyl refraction..thanks i will continue to flow you until i understand it..as a eye optom cyl is my hardest want .but thanks a lot

[@nevenabratanova7621]

It is the best explanation ever! Thanks:), sir! It made sense!

[@wakalabakataka]

great explanation

[@anshumang.216]

Very informative vdo . Thank you Sir

[@Kasia170490]

Great video, very helpful

[@Odank]

Great tutorial! Your example featured a + sphere example. In myopic minus patients, the same increase in cyl power (once best vision sphere has been determined) would follow the same rule for compensating sphere power with higher cyl power but in this case decrease the sphere by 1/2 of the cyl (by 0.75 as in your example)? Or does this only apply to plus powers? So for a -3.50 best sphere, every 0.50 diopter increase in the required cyl would drop the sphere by 0.25? If not the case, can you please explain why?

[@otissumnerbrown]

Thanks for this detailed description of a very difficult measurement process.

[@eyecareprogrammss7122]

Sir.This course hava Certificate give me.

[@otiebrown9999]

Great presentation. Thanks.

[@wiZZelify]

Is it normal to have an astigmatic vision in ajustment period with my glasses? I have astigmatism

[@adelalraisi5159]

such great effort... thanks

[@skinfo901]

Bro my right eye cylinder number is -0.50 and axis is 170 degree if i apply 180 degree what will be the damage

[@hungduong2628]

Verry good

[@c6r4n2]

Thank you for posting this video! I find it very helpful. However, I have a question: what if in the case presented the patient has a hyperopic astigmatism with a 90 degree axis corrected whith the same position as for a myopic astigmatism with 180 degree axis?

[@c6r4n2]

Ian Squire Thank you for your answer. I know my question was ambiguous, things are clearer now. Actually, you have pinpointed to a problem, and that is, the use of either plus or minus cyl. I have heard different versions on whether to prescribe plus or minus cyl. Personally, I prescribe whatever is more comfortable. Are there any special cases that might require a plus instead of minus cyl? Thank you once again for these videos and for your time!

[@Rooker11111]

Ian Squire The +1.00 blur test isn't needed if the wearer can read the 6/6 line without effort. It proves that the circle of confusion has gone away.. Anything lower than 6/6 isn't needed to be aimed for, as the goal is to give the patient 20/20 vision. Going below 6/6 is overcorrecting.

[@Rooker11111]

+Ian Squire Can convex cylinders be used to refract myopes?

[@Odank]

@@Rooker11111 Isn't the point if this ti determine if indeed there is slight over-correction in that case? If the +1.00 only takes back the patient a line or two, then that mean there is room for refinement. The patient would be able to read 6/6 even with over correction to a degree. I don't think the goal is to correct for below 6/6.

[@optykoptomal8206]

It is very helpful video, but my concern is that not all of the decignations of the cylinder axis (when we using cross cyl) has been explained, for example when we looking for first preliminary axis astigmatism, we looking it in 4 positions our cross cyl 90 and 180 like you show and between 45 and 135 deg and then we can find first axis and then just it clarified. I understand that you wanted to explain il as simply as it is possible, but mayby can you post an expanded version. ;-) Kind regards Alex

[@optykoptomal8206]

I think that yours videos are gerat. If you want I can help ;-) we can do something like brainstorm :-) I' ve got some my obserwations when I do the refraction with cross cyl. Regards Alex

[@optykoptomal8206]

I think that Rooker11111 was thought about the Osterberg duochrome binokular test for balancing the stimulus accommodation ( Binocular Balance Verification).

[@optykoptomal8206]

www.google.pl/imgres?imgurl=netzpolska.pl/products_img/normal/4d02525d96b9f.jpg&imgrefurl=netzpolska.pl/grupy/show/polecane/view-m_vcl-1900.html&h=246&w=282&tbnid=OdZ21UB1qyWlUM:&docid=2NfW2LmuZH7S3M&hl=pl&ei=XpQwVuCEKIaCzAOnobSABQ&tbm=isch&ved=0CGAQMyg3MDdqFQoTCOCrxZ_s5MgCFQYBcwodpxANUA

[@optykoptomal8206]

This kind of tests (duochrome) we use with polarization at the end of the sight test (this is a binocular test)

[@amandawen4158]

hi sir! in step 6, if there is any changes when giving extra -0.25 or +0.25 , what should i do next? Take the +0.25 for example. For reaching MPMVA, i need to add the +0.25. Add to the sphere? and from which step i need to start over again?

[@rinajoyjoven8400]

I have cataract 0.50 left and 0.25 in right eye , it is all right ? It is not have increase cataract ?

[@waialicia4087]

At step 4, when u change the cylinder from -0.50 to -1.00, I think the sphere should increase from +3.50 to +3.75. Am I right? Great video by the way. Thanks lot. :)

[@timothyhurlburt9562]

I actually believe Mr Squire is correct. To that point in the refraction he did not compensate for the cyl he added. He started with no cyl and added -1.00 total cyl at that point. To compensate, he added half the cyl as plus sphere |-1.00DC|/2 =+0.50DS, thus +3.50 to +4.00. My only critique is that this should be done at each step, although maybe this is standard to save a little time.

[@shinebright3798]

can you teach us how to do the subjective test without the jackson cross cylinder .. i mean how to use the lenses in the case if we don't have a JCC ??? please ..

[@shinebright3798]

Ian Squire i have just seen it .. thank you so much ! 🤗 ^^

[@bothianakhalifa]

Thank you indeed 🤓

[@yogitauma4495]

that was very helpful.. thanks :)

[@philwang9878]

HELLO IAN WILL U DO A SERIES OF VIDEOS ON BINOCULAR VISION AND WHEM TO PRESCRIBE PRISM

[@يحييعلي-ع8ل]

ححح

[@marnellecorsiga6747]

perfect!

[@gaborapo41]

Hi! Could you explain in some of your future videos how the JCC works? Or rather my question is, why as the cyl will be a half dioptre increased , schould be the sphere only a quartet increased? In my practice it works very well and I do that always like that. But it is for me just a roule ,and I miss the conception behind of it. Thank you for your answer , and best wishes from me to You, Gàbor from Budapest...

[@chackbass5821]

Thank you thank you 👍😍😍

[@MrChandugowda]

Dear Sir iad come up with confusion, while you tested CYL Power Refinement using +/- 0.50JCC, where the patient got Visual improvement with -0.50JCC so in this juncture you increased CYL power by -0.50 to the CYL in trail frame and also +0.50DSph.Aand again you done JCC using +/- 0.25 in 1st VA improved by enhancing by -0.25 JCC and increased -0.25D CYL to CYL in trail frame and agaian did JCC with +/- 0.25 here also VA improved by enhancing by -0.25 JCC and increased -0.25 CYL to CYL in trail frame. SO in final you icresed +0.25DSph to SPH in trail frame and -0.50CYL increased to CYL in trail frame. My confusion is why you increased only +0.25 to Sph why not +0.50 SPH as you increased to CYL. Please clear my confusion sir

[@ckgamit007]

Hello sir, I liked your video, but I have a problem, we need this video in Hindi, please help sir

[@Abbas.786]

Rest in Peace Ian.

[@sula99]

I think at 4:20 you meant to say axis rather than meridian....

[@sula99]

+Ian Squire Thanks, I only picked it up because the nomenclature of axis/meridian was the most difficult part to learn for me. Excellent video though, a great way to consolidate these techniques!

[@Rooker11111]

+Ian Squire Which objective refraction is more precise: retinoscopy or autofraction?

[@azizur19]

great

[@يحييعلي-ع8ل]

حح

[@يحييعلي-ع8ل]

ح9