Fan and Block

Fan and Block used to be a common method for correcting astigmatism but has been superseded by the cross cyl technique. It is however still a useful method especially when dealing with larger cyls and sometime patients finds the fan and block method less confusing. Its certainly a useful backup especially in situations where hi tech equipment is not available.

[@NAMPAKY]

I missed my lecture on this. This is a life saver, thanks.

[@nonexistenty4152]

Thank you for this informative video. It is extremely helpful for me

[@IqbalKathrada]

Wish you were my lecturer in university Ian.

[@modathirreads-551]

From Sudan, thanks a lot.

[@abibridge2603]

We use minus spheres to activate accommodation for Cross Cyl, can you/anyone explain why this is important in terms of the COLC and focal points?

[@dharshanakumar]

Hi Ian,sorry it may sound silly,cant you put +0.50 with spare (to bring 2nd focal point infront of ret) before even turn on fan and bloack chart?

[@erikahmadhasyim9768]

i'm sorry sir, can i get explanation about how you determined the X is 100,
Thank you for your great video

[@ash1982ification]

Hello sir kindly upload a video on fogging method. Thanks

[@kapilhrathaur007]

sir plz also explain in new video madox rod and worth 4 dot test and glare test.

[@sabithavibash5125]

Thank you soooooooooo much Sir

[@MrThecrazyzombie]

my left ear enjoyed this

[@namithavijayan4881]

Anyone pls tell me how he choose that 100degree axis and why he turn the arrow in clockwise direction...plss

[@aleksandraszczepanik8052]

Very clear explanation. Thank you!

[@deepuv9150]

I confused with adding minus power.

[@abduomo9845]

i just did nt got whay Alen started with +1.Is it because u have + ve prescription or is something that we have to do prior to fan and block. appreciate any help

[@abduomo9845]

+Ian Squire many thanx ur videos are hepling me a lot in my optometry education.

[@wefaqalssaqaf9724]

i donot understand the axis chosen

[@wefaqalssaqaf9724]

+Ian Squire thank you so much i think i got it now

[@OptometryAcademy]

Good explanation sir :)
#optometryacademy

[@mayurparmar5376]

no audio

[@saff1257]

principle:
Find BVS with a subjective or ret test. bring 2nd FL to ret with pos. bring 1st FL to ret with neg.
test: occlude one eye. use BVS fo estimate the cyl power, add half the pos cyl to get 2nd FL onto ret. adjust the axis. (at 90* to test chart axis). add 0.5 sph plus as a check for later. now onto blocks. need to add minus cyl until blocks are equally blurred. the check: remove the 0.5 sph and there should be a reversal of block clarity.

[@michaelan6925]

This summary got multiple points wrong.

[@VILLENISLIVE]

I m here

[@oedevil1291]

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[@VILLENISLIVE]

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