Annoying Quirks You Encounter When Doing Optometry

[Optogal]

Hey folks

I'll describe some annoying "phenomena" that occur frequently enough when practicing optometry. Feel free to add your favorites.

1. The unbalance prism-balance
You guys have all seen this. Monocular subjective right eye then left eye. 20/20 OD and OS. Now you prism balance. Lo and behold, you find out one of the eyes (OD) are "over-minused" by like 0.50 D. So you add the appropriate lenses, remove the prisms, then reduce the fog binocularly. 20/20+ OU. But you have this odd feeling, so you occlude OD and find out it now only sees 20/25-. So you balance again, double-checking your result, but again end up at the same "balanced" endpoint, which is unbalanced. It's annoying. I usually add a bit more minus to OD to get it to 20/20, and keep the OS endpoint, but I hate how things don't "add up", and how I've wasted so much time on the balance on this patient only not to use the end result.

2. Cyl search that ends nowhere
I'm sure you guys have all seen this too. Ret starting point no cyl. So you do the cyl power search. At 180 they take red. OK. So you start searching for axis. They take you to 45 degrees. At 45, you do a power search and at -0.25 cyl, they take white. You're like what?? What I usually do is start at 180 again, check that they take red at 180, then do an axis search again. Invariably, some patients again take you to 45 degrees, only to take white. Again, annoying for wasting time on a measurement that doesn't add up. What do you guys do in this case? I give the -0.25 x 180 if they like it on a direct comparison, otherwise I just ignore the cyl.

OK. Your turn.

---

Members don't see this ad.

 

[Optogal]

One more.

3. Uncontrolled cyl on JCC
This one is due to patient idiocity. Patient has like -0.50 cyl on ret. You're now confirming the power using JCC. For some reason, they just take red. No matter what, they take red all the way to like -2.75 D. You're sitting there wondering - cause their old glasses has close to -0.50 cyl and they saw 20/20 on entering VA. So you click up to -2.75, shaking your head all the way. At -2.75, you stop and check their VA. You get 20/40. So you start back at -0.50 (where they see 20/20) and do it all over again. Again, they just take red forever, take you up to -2.75 DC and 20/40, and again, you've wasted your time on a result you won't use. I hate when this happens and I don't understand why it's as common as it occurs.

The opposite of this can also happen, when they start with -2.75 cyl, and take white down to -0.25, only to lose 3 lines of VA. You double-check, and again you get the same result. Annoying.

 

[KHE]

Hey folks

I'll describe some annoying "phenomena" that occur frequently enough when practicing optometry. Feel free to add your favorites.

1. The unbalance prism-balance
You guys have all seen this. Monocular subjective right eye then left eye. 20/20 OD and OS. Now you prism balance. Lo and behold, you find out one of the eyes (OD) are "over-minused" by like 0.50 D. So you add the appropriate lenses, remove the prisms, then reduce the fog binocularly. 20/20+ OU. But you have this odd feeling, so you occlude OD and find out it now only sees 20/25-. So you balance again, double-checking your result, but again end up at the same "balanced" endpoint, which is unbalanced. It's annoying. I usually add a bit more minus to OD to get it to 20/20, and keep the OS endpoint, but I hate how things don't "add up", and how I've wasted so much time on the balance on this patient only not to use the end result.

Dissociated prism balance is a dreadful technique and should be avoided at all costs.

2. Cyl search that ends nowhere
I'm sure you guys have all seen this too. Ret starting point no cyl. So you do the cyl power search. At 180 they take red. OK. So you start searching for axis. They take you to 45 degrees. At 45, you do a power search and at -0.25 cyl, they take white. You're like what?? What I usually do is start at 180 again, check that they take red at 180, then do an axis search again. Invariably, some patients again take you to 45 degrees, only to take white. Again, annoying for wasting time on a measurement that doesn't add up. What do you guys do in this case? I give the -0.25 x 180 if they like it on a direct comparison, otherwise I just ignore the cyl.

OK. Your turn.

If a patient has a spherical objective refraction result and refracts to 20/20 with a spherical correction, you will find that even if you DO fine -0.25 cylinder you will NOT prescribe it 99.99% of the time because 99.99% of the time, prescribing that quarter cyl causes more eyestrain, headaches etc. etc. than it ever solves. My best advice is to not even try to refract cyl in those cases.

 

[KHE]

One more.

3. Uncontrolled cyl on JCC
This one is due to patient idiocity. Patient has like -0.50 cyl on ret. You're now confirming the power using JCC. For some reason, they just take red. No matter what, they take red all the way to like -2.75 D. You're sitting there wondering - cause their old glasses has close to -0.50 cyl and they saw 20/20 on entering VA. So you click up to -2.75, shaking your head all the way. At -2.75, you stop and check their VA. You get 20/40. So you start back at -0.50 (where they see 20/20) and do it all over again. Again, they just take red forever, take you up to -2.75 DC and 20/40, and again, you've wasted your time on a result you won't use. I hate when this happens and I don't understand why it's as common as it occurs.

The opposite of this can also happen, when they start with -2.75 cyl, and take white down to -0.25, only to lose 3 lines of VA. You double-check, and again you get the same result. Annoying.

Obviously, you are just learning how to do subjective refraction. It's good to learn the theory behind all of it obviously but as you are clearly learning, it's not a perfect test.

With experience, you will learn quickly that when things don't add up, like in this case you've described you should not simply follow the cook book recipe of refraction. Unfortunately, it just takes experience to learn NOT to "shake your head all the way" because you will stop much much sooner.

Clearly, a patient with 20/20 entering acuity and -0.50 cyl in their glasses is NOT undercorrected by 2.25 diopters of cyl.

Often times, in those patients I won't even refract cylinder because in these patients, making small changes in cyl cause more problems than they solve. Again, just comes with experience.

 

[Optogal]

Dissociated prism balance is a dreadful technique and should be avoided at all costs.

What do you suggest instead?

If a patient has a spherical objective refraction result and refracts to 20/20 with a spherical correction, you will find that even if you DO fine -0.25 cylinder you will NOT prescribe it 99.99% of the time because 99.99% of the time, prescribing that quarter cyl causes more eyestrain, headaches etc. etc. than it ever solves. My best advice is to not even try to refract cyl in those cases.

I have trouble agreeing with you that in 99.99% of the time, 0.25 cyl causes headaches, eystrain, etc. etc.

 

[Optogal]

Obviously, you are just learning how to do subjective refraction. It's good to learn the theory behind all of it obviously but as you are clearly learning, it's not a perfect test.

With experience, you will learn quickly that when things don't add up, like in this case you've described you should not simply follow the cook book recipe of refraction. Unfortunately, it just takes experience to learn NOT to "shake your head all the way" because you will stop much much sooner.

Clearly, a patient with 20/20 entering acuity and -0.50 cyl in their glasses is NOT undercorrected by 2.25 diopters of cyl.

Often times, in those patients I won't even refract cylinder because in these patients, making small changes in cyl cause more problems than they solve. Again, just comes with experience.

I think the simple explanation is that some patients just instinctively say the wrong number i.e. when they see "2" clearer, they say "1". It may take the practitioner to point out their mistake for them to realize it.

 

[JMU07]

Number 1 drives me nuts. It's not usually an issue with adults, but kids don't get it a lot of the time. They also love to run around on JCC, I've learned how to stop that in its tracks. Probing with -0.50 instead of -0.25 helps a lot. If they take more than half a diopter over what I'm expecting, I ask them if either image is clear. Generally they're both "really blurry".

Also, I incorrectly assume that people will tell me when they look the same. Unless I explicitly state "It's okay if they look the same" they'll keep going forever. Or if I ask them 1 or 2 and they hesitate for more than 2 seconds.. that means they're the same.

 

[KHE]

What do you suggest instead?

I tend to not use phoropter for refraction so I use the red/green balance test.

I have trouble agreeing with you that in 99.99% of the time, 0.25 cyl causes headaches, eystrain, etc. etc.

I didn't mean to imply that 0.25 cyl causes a problem 99.99% of the time. Sorry.

I meant that when you DO prescribe that 0.25 cylinder on a 20/20 patient who is habitually wearing a spherical correction, if it does do anything (positive or negative), it will cause a problem 99.99% of the time. Then they end up back in your office 2 weeks later complaining that their new glasses "just don't feel right."

 

[KHE]

I think the simple explanation is that some patients just instinctively say the wrong number i.e. when they see "2" clearer, they say "1". It may take the practitioner to point out their mistake for them to realize it.

Sometimes it's that. Sometimes people (especially children) will just say whichever number is higher.

But the point I was trying to make is that a patient who is 20/20 with some prescription that has -0.50 cyl in it, their final cyl rx from refraction should not be different by more than -0.25 most of the time. Once you get past a -0.50 change from their 20/20 habitual, you should start thinking that's something smelly in those cases.

 

[KHE]

Number 1 drives me nuts. It's not usually an issue with adults, but kids don't get it a lot of the time. They also love to run around on JCC, I've learned how to stop that in its tracks. Probing with -0.50 instead of -0.25 helps a lot. If they take more than half a diopter over what I'm expecting, I ask them if either image is clear. Generally they're both "really blurry".

Also, I incorrectly assume that people will tell me when they look the same. Unless I explicitly state "It's okay if they look the same" they'll keep going forever. Or if I ask them 1 or 2 and they hesitate for more than 2 seconds.. that means they're the same.

lol. Yes, that is frustrating. Even if you specifically tell them that "same" IS in fact a choice, they will pick either 1 or 2 even if they both really are the same.

I recall a comic strip in our student clinic titled "student refraction" in which the doctor in the comic was asking "86? or 87?"

Everyone will learn quickly when patients are giving you answers that make no sense.

 

[Ryan_eyeball]

lol. Yes, that is frustrating. Even if you specifically tell them that "same" IS in fact a choice, they will pick either 1 or 2 even if they both really are the same.

I agree with this 99% of the time. In kids, I go with my dry or wet retinoscopy the majority of the time, esp if the kid is under 9. Some kids are very intelligent and can understand a subjective refraction. Most are just a waste of time with a suj. refraction. They pick the same number every time, or the higher number every time.

My way...do a dry ret. Read down as far as possible, a lot of time 20/20 lines unless there is a B.V. issue. If the kid can read 20/20 with ret then add +0.50 sph, show a different 20/20 line, which should be blurry.

 

[Caffeinated]

It's been a while since I refracted someone (I've been out of optometry for a while). But I distinctly remember these phenomenon. I discovered a few months into practice that some people don't have the mental capacity or the short-term memory retention to do a reliable subjective refraction. There are people who will choose the second choice, regardless of what you call it. When I suspected this was happening, I would pause, show them the same two choices in reverse order, and watch them continuously take the second choice. Sometimes you have to point out their inconsistencies in order to make them snap out of it.