In optometry school, we’re trained to perform all of the detailed parts to a thorough refraction. We can binocular balance, perform NRA/PRA and even test phorias and vergences. When we’re out in practice, however we must remember that these are all tools that give test results. We then use our clinical knowledge to compile these results and determine a final glasses prescription for our patients that will provide them with clear, comfortable vision. Despite our best efforts there will be times when our patients come back unsatisfied with the glasses they purchased (from us or elsewhere). It is important to have a troubleshooting protocol in place to find a satisfactory solution to these patients’ complaints. We can also minimize some of this dissatisfaction if we keep certain principles in mind during our exam.
This article will discuss some tips and strategies to help reduce the number of patients returning to your office for glasses redos. We will also outline a systematic approach to troubleshooting new glasses prescriptions that patients are dissatisfied with.
Tip #1: Don’t cut minus in a myope
When I’m performing my exam, I often find patients are over-minused in their current glasses. Of course I instinctively want to cut them back to their maximum plus maximum VA, however they likely wouldn’t be very happy with those glasses. So here’s what I do:
If I find a non-presbyopic patient is over-minused, I will first ask whether they are having headaches or eye strain when doing near work. (Many times they are!) If they are, then I will trial frame the new prescription at distance and near. In this case, I will either prescribe single vision glasses with less minus (but likely not the full amount I found on refraction) to make the patient more comfortable at near. In other cases, I will prescribe an anti-fatigue lens where I keep their distance Rx stronger but give them some accommodative relaxation at near. I also explain to the patient what I am doing and why.
If I have an early presbyopic myope who is over-minused in their single vision glasses and has near complaints, sometimes just cutting back the minus can let them hold off on needing a progressive for another year or two (especially if the patient is averse to switching to a PAL). Anti-fatigue lenses are also great “training wheels” for those early presbyopes who don’t yet want to go into a bifocal but aren’t content with single vision lenses.
So it’s not that I never cut minus in a myope—sometimes you need to. However, you need to first be sure that’s the answer to their problems and that you’re not creating a new problem.
Tip #2: Don’t overplus a presbyope
How many times do we see a 55 year old hyperopic patient using +1.50 OTC readers for near, who hasn’t had an eye exam in 15+ years and doesn’t wear any distance correction? Sometimes they’ll even start to find themselves walking around with these OTC readers. On refraction, you find they’re a +1.75 in the distance, and during near testing also tell you they prefer another +1.50 add for near. Do you prescribe the full correction? Likely not!
Don't simply prescribe an add based on age!
One of the biggest mistakes new grads make with regard to prescribing an appropriate add power is to prescribe solely based on the patient’s age without considering what the patient’s complaints and visual demands are. Does the patient have any distance complaints uncorrected? Does the patient use a computer? If so, is it a desktop, laptop or do they mean they use a tablet? What about a cell phone? Do they work in an office? Maybe the patient doesn’t spend much time reading books or online articles, but is a carpenter and needs to see a tape measure at arm’s length.
You must consider their current correction being used and the patient’s work environment. It’s frustrating for both patient and doctor when the patient comes back in after getting new reading glasses/bifocals/progressives and they feel they have to get too close to what they’re doing in order to see clearly. One way to avoid this is to find out where the patient is having problems seeing. If the aforementioned patient doesn’t have any distance complaints and truly wants to continue with near only glasses, I certainly would not prescribe the full +3.25 NVO. Keep in mind that this patient was only used to a +1.50 OTC NVO previously. Trial framing and prescribing somewhere in between will likely be in the best interest for the patient. Remember, this patient is also accustomed to the working distance of a +1.50 (probably holding things far away).
Now the fact that this patient will sometimes walk around with these glasses tells me that they actually could see better in the distance. This would then lend to a conversation about possibly trying a PAL or bifocal Rx.
Figure 1: Be cautious when prescribing first-time distance glasses in a presbyope. While they may prefer the clear vision shown through the phoropter, the dynamic experience of wearing glasses will likely provide a very different visual experience. Also, when prescribing bifocal or progressive lens options in these patients, try to match what their eyes/brain are used to seeing with their current OTC readers.
Another great option for presbyopic patients who are essentially emmetropes and don’t regularly use a distance Rx are office space lenses. These glasses are not for driving, but unlike NVO, patients won’t have to remove them when walking around the office or look over the top of them. These progressive lenses give a small distance Rx up to about 10 feet, an enlarged intermediate zone (perfect for computer use) and sufficient reading area. These work great for patients working in office settings.
Tip #3: Be careful of cylinder axis
A patient comes to see you stating they got new glasses elsewhere but they feel “off” with them. They admit their vision is clear but just feel weird walking around with them and that things that should be straight appear tilted. Or maybe they’re noticing new onset headaches with their latest glasses. You saw the patient several years ago and you compare their old Rx with this new Rx. Initially you can’t find the problem—the sphere and cylinder powers are the same as what the patient already wore. Then you realize the cylinder axis is different by 20 degrees! Now, with small amounts of cylinder, this isn’t as noticeable, but with a large amount, this can really throw someone off.
Remember ANSI standards tell us what amount a glasses can be “off” from the prescription and still be acceptable because the difference is so small it will not be perceived. Remember that this “just noticeable difference” (to borrow a low vision term) changes for sphere, cylinder power and axis depending on the amount.
So what do you do if you find a large difference in cylinder axis on refraction compared to what the patient is wearing habitually? First, I would open both the patient’s eyes in the phoropter or trial frame and move the axis wheel to see if the patient can appreciate an improvement to their vision with the new axis. Oftentimes, they don’t notice a difference with both eyes open. If they can’t notice a change with both eyes open, there is less reason to make a shift that is going to make them feel “off” with their new glasses. If they do notice a big difference, I would prescribe the cylinder axis more in the direction of what they liked without changing the axis by more than 5-10 degrees (depending on cylinder power). Any cylinder changes greater than 10 degrees can increase the likelihood of headaches or asthenopia with new glasses prescriptions.
Carefully explaining to the patient that it may take some time to adjust to the new Rx is also crucial. It is better to make smaller changes, and the next year you can always move more in the direction of what they prefer.
Now, for the patient above, I would also repeat a refraction and prescribe more similarly to their old Rx that they felt more comfortable with.
When we’re new clinicians, we want to give everyone the best possible vision monocularly, but forget that our patients don’t just sit behind a phoropter all day but move through the world wearing glasses. We have to think about our patient’s perception and visual comfort when prescribing.
Tip #4: Be aware of refractive shifts in uncontrolled diabetics
A patient comes to see you stating their vision has changed significantly over the past 3 months. They previously needed glasses for reading and now see better at near without any glasses and cannot see far away! They explain that a few weeks ago they weren’t feeling well, went to the doctor and were found to have blood sugars in the 700s. They were started on medication for diabetes along with an intensive dietary plan and are feeling much better.
Of course, you begin your exam concerned that this patient has diabetic retinopathy as you don’t know how long they’ve truly had diabetes. But moreover, you know you are not going to prescribe glasses at that visit. Perform a refraction so you know the patient’s refractive status, but explain to the patient that as their blood sugars stabilize, their vision is going to continue to change and should go back to how it was before. Encourage the patient in their journey to control their blood sugar and give them a few months for their blood sugars to stabilize before finalizing a glasses Rx.
Sometimes, even though the blurry vision may only be temporary as the blood sugars stabilize, you may need to prescribe glasses for the patient for the interim (depending on living/driving demands, etc). Explain to the patient that their vision is going to change once their blood sugars normalize. If you have a lab at your office, have a policy for situations like these where the patient is allowed 1 re-do when their sugars stabilize. If you don’t have your own lab, ensure you are using a lab that allows for an Rx redo policy within a specified period. This allows you to order a patient glasses so they can function in the interim with the expectation that the prescription will change and you can finalize the Rx once that time comes.
Depending whether the shift was hyperopic or myopic, sometimes a patient may be ok with OTC reading glasses in the interim when before they needed an Rx. If that’s possible, go with that as an intermediate option. Better yet, if the patient wears contact lenses already, consider giving them some trials in the new Rx and check back in every month or so until their sugars stabilize, then finalize the glasses and contact lens prescriptions.
Tip #5: Have a troubleshooting protocol in place for patient complaints
Say you did a careful refraction, ensured you’re giving the patient clear, comfortable vision by trial framing, and you didn’t even change their prescription very much from their habitual pair of glasses that satisfied them. However, when the patient gets their new glasses, they can’t see well! Now what?
- Dot optical center for single vision glasses prior to sending to lab: especially for high Rx’s and/or larger frames
- Check for prism (both intended and unintended): Dot optical center in patient’s habitual glasses and use manual lensometry to check for prism in habitual pair and see whether you changed this in new Rx
Figure 2: Dotting where the patient’s pupils are in their new glasses can provide useful information and reveal potentially unintended prism (vertical or horizontal), or even the wrong Rx altogether (possible in bifocal/progressive lens options with errors in seg height measurement)
- Compare frame size & shape: sometimes patients switching to a much larger frame or wrapped frame may cause them to feel “uncomfortable” or notice peripheral distortions more. Consider keeping frame size/shape more similar to habitual.
- Lens material: some patients are particularly sensitive to polycarbonate and are more aware of chromatic aberration and peripheral distortion than others. If no change in Rx was made and similar frame shape/style, determine material of previous glasses and keep consistent. Notify patient so they can be aware for future glasses made.
- Progressive seg height: patient may have to lift or drop chin in order to see more clearly in the distance or lift glasses up to read. Re-measure seg height ensuring patient is in natural position while measuring. (eg when driving does the patient recline back?)
- Induced prism: Always remember to measure the PD for the working distance/task the patient will be performing while wearing the glasses and ensure their glasses order has this PD (and not one set for infinity)
- Patient doesn’t like the frame: Sometimes a patient will make a lot of vague complaints—whether saying the frame is uncomfortable or they can’t see well, none of which can be solved with any of what you do above. In these situations, really try to dig in and see what the patient’s main concern is. Did their friend tell them the look was too bold and now they’re feeling self-conscious or doubting whether they made the best selection? Within a reasonable amount of time, most labs should allow for a frame change. Just make sure as you use this one redo that you make any other changes to the prescription or other measurements that also may need to be changed.
In conclusion, while we always have the best intentions in providing satisfactory prescriptions for our patients, they may return dissatisfied. Remember, refraction is a test. You are a clinician. You take the results of various tests, combine it with your clinical expertise and understanding of visual perception to then prescribe the final glasses Rx. All clinicians will have some glasses redos, no matter how many years in practice. It is important to remember that we can minimize that amount by keeping the above framework in mind.