The portable SVOne Autorefractor by Smart Vision Labs

What Is the Gold Standard: Subjective or Objective Refraction?

A Practical and Complementary Approach to the Gold Standard of Subjective Refraction– Wavefront Refraction

We recently held a webinar with optometrist Dr. Tihomira on how to incorporate telemedicine into your optometry practice. Dr. Tihomira is a leading optometrist who embraced telemedicine and is influencing the technology development. One of the main topics she discussed was how automated refraction and telemedicine technologies are challenging the gold standard of subjective refraction. Subjective refraction is widely accepted as the optimal refraction method in the industry, despite how variable the process can be. So if subjective refraction is not necessarily the most repeatable method, why is it still considered to be the best way to determine someone’s prescription?

The use of a manual phoropter to conduct a subjective refraction continues to be considered the gold standard in the industry. The question is why? This process is influenced by multiple factors including; the ambient lighting of the room, the quality of the projections system, the cognitive awareness of the doctor and the patient during the process, and both the doctor’s and patient’s previous experience with refraction. All these factors play a role in the determination of the final prescription and the accuracy of that prescription.

Doctors try to control as many variables as possible but ultimately refraction remains a very variable process. A clinical study published by Bullimore illustrates the variability of subjective refraction. The study compared refractions done on the same patient by two separate clinicians and found that, for sphere, the 95% limit of agreement varied from -0.9 D to +0.6D. The study also reported that automated refraction is more repeatable than subjective refraction.

Automated Refraction

Wavefront aberrometry is challenging this gold standard of subjective refraction due to the repeatability of its results. When measuring the visual performance the technology assesses two components of the visual system: the optics that form the retinal image and the neural processing that transforms the retinal image into perception. Subjective refraction has historically been unique among methods of refraction. In considering both components in asking the observer to choose between a series of options, the goal is to optimize visual acuity.

However, wavefront aberrometry together with visual image quality metrics are changing the old model. A study published this year by Hastings et al. showed that 72% of patients preferred prescriptions generated using wavefront aberrometry optimized by visual image quality matrix, compared to prescriptions generated by subjective refraction. The SVOne autorefractor will include wavefront aberrometry in September of 2017.

The SVOne Technology

The SVOne autorefractor uses Shack-Hartmann wavefront autorefraction to capture 3 images per eye, taking 3 seconds per eye. Through the analysis of up to 120 points, a Zernike decomposition algorithm extracts the low order aberrations and converts them to sphere, cylinder, and axis. There are several unique features of the instrument, one of them is a least-squares reconstructor algorithm that adapts to pupil size on the fly. The device also features an open field design with machine learning algorithm allowing the system to – as soon as optimal pupil alignment is achieved – autocapture the measurements, thus eliminating proximal cues and limiting accommodation.

The SVOne is capable of measuring a wide range of refractive error, from -14 D to +14 D sphere, up to -7 D cylinder in 0.01D increments and axis measurements in increments of one degree. As you can appreciate from the image shown here, the device is very small, nothing like the autorefractor you are likely to find in most optometric offices. Additionally, it weighs less than 1 pound. To make the transfer of data easy, the device has the capability to store data in a HIPAA compliant cloud platform that can send data to your EMR.

Clinically Proven Accuracy of the SVOne Autorefractor

Clinical study data has been able to highlight the accuracy of the SVOne autorefractor. A study published by Ciufreda et al. in 2015 showed that SVOne refraction is accurate and has higher repeatability than subjective refraction. The study was conducted using 50 normal adults age 18 to 34, all correctable to normal vision. For all subjects retinoscopy, SVOne refraction and subjective refraction were determined and the difference between each of the findings and subjective refraction were quantified using the 95% limit of agreement.

data results from Smart Vision Labs clinical study

The table above shows the values calculated for the 95% LOA in diopters for retinoscopy and SVOne refraction as compared to subjective refraction. The table shows that for sphere, retinoscopy and SVOne show the same limit of agreement. Also, this finding shows that SVOne sphere measurements have variability similar to that of subjective refraction between clinicians as previously reported. The SVOne measurements for cylinder and axis were a bit more variable than retinoscopy, but as the authors concluded that could be due to alignment error, something that has been addressed by the introduction of a stand to which the instrument can be attached to, thus virtually eliminating misalignment errors and contamination of cylinder and axis measurements.

2-subjective-or-objective-refraction-data

The next table above shows repeatability data of 10 subjects. The data shows that SVOne refraction had higher repeatability than subjective refraction. This finding is again consistent with previous reports by Bullimore et al. showing that automated refraction is more repeatable than subjective.

The adult study was very strong but clinically we also needed to test the accuracy of the device on the majority of the population. A study was conducted to test how well the device performs within the pediatric population. Conducted by Rosenfeld et al., the study showed that SVOne refraction is also accurate in children and has higher repeatability than subjective refraction. The study was conducted using 40 normal children age 5 to 17, all correctable to normal vision. The study followed the same design as the adult study.

3-subjective-or-objective-refraction-data

The table above shows the values calculated for the 95% LOA in diopters for retinoscopy from SVOne refraction as compared to subjective refraction. The data shows that while sphere measurements using retinoscopy were a little bit more accurate, SVOne refraction varied by only additional +/-0.2 D, less than a quarter of a diopter. And both methods showed the same LOA for cylinder and axis.

4-subjective-or-objective-refraction-data
The next table above shows repeatability data of 5 subjects. The data shows that the SVOne has the highest repeatability across all components of the refraction, sphere, cylinder and axis. The study confirmed that the SVOne is an accurate and repeatable way to measure refractive error in children.

SVOne Refraction: The New Gold Standard?

Through clinical studies and the feedback and results from doctors using the SVOne, we were able to conclude that automated refraction and the SVOne are certainly challenging the gold standard of subjective refraction due to the accuracy and repeatability of refraction results.

SVOne technology is a practical approach to solve the challenge when subjective refraction is too costly or unavailable. If you are running multiple optical retail stores, and have difficulties to capture walk-in customers due to lack to ability to provide on-site vision exams. SVOne is the perfect solution to provide fast and accurate eyewear prescriptions to your customers. If you are running a mobile clinic, and conducting manual refraction is too cumbersome, SVOne is the solution to provide clinically proven vision care to your customers. If you are running an overseas mission trip, and facing thousands of patients in the duration of a few days, SVOne is the portable solution that can offer efficient vision exams in a big way.

If interested in learning more about the SVOne autorefractor, request a demo to see the refraction process.

Demo the SVOne Autorefractor

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How to Grow Your Business with Portable Autorefractors with Smart Vision Labs CEO Yaopeng Zhou

How to Grow Your Business with Portable Autorefractors

How to Grow Your Business with Portable Autorefractors

We recently held a webinar on how an advanced autorefractor can grow your business. Smart Vision Labs’ CEO and inventor of the SVOne technology, Yaopeng Zhou, touched upon a range of topics from the facets of the technology itself, to the sectors where portable autorefractorsare being used and the results that have been seen in those very sectors. Whether being used in a mobile optometry practice, optical retail store, mission service trip, or even in determining the next best Major League Baseball player, our advanced, portable autorefractor has helped our partners achieve excellent results for themselves and for their patients. Below are some highlights from the webinar to help take your practice or retail operation to a whole new level.

“What’s the evolution of the Smart Vision Labs’ SVOne Autorefractor? What was the process and can you provide a little bit of the backstory behind the design?”

The inspiration for Smart Vision Labs started out 4 years ago when I read an article saying there are over a billion people around the globe who suffer from uncorrected vision. Back then there were two reasons for that: number one was due to the lack of access to eye care professionals, and number two was that the existing technology was often too bulky and expensive. So the inspiration was to build something I could put in my pocket that anyone could easily use. Fast forward 4 years, here we are with our latest device release. And the story behind the device is pretty interesting from an engineer and designer perspective. Our old initial design in counter with market feedback taught us a lot. That’s why in the last 3 years we’ve launched 3 generations of autorefractors. We received a ton of feedback from the market as well as from the over 500 doctors using our device. This feedback is what led to the release of this current generation.

The biggest change with the current generation is with the physical appearance and, specifically, the stand we now use that dealt with some issues our partners’ were encountering with alignment. The first generation was a handheld device, and we noticed subtle differences depending on who was administering the exam due to how they were holding it and the overall differences in hand stability. When measuring sub micron level precision, every little thing matters. So we took what we learned from market feedback and put it an adjustable, physical stand to stabilize the measurement process. We also optimized the software.

“If I’m running a practice – say I’m an optometrist or ophthalmologist – how long would it take to train my staff to use the device?”
I would say no more than 30 to 45 minutes to train someone on using the device. And I wouldn’t even call it training, I would call it guidance and just becoming familiar with the process.

“So what does the future evolution of the product look like?”
It’s really digging into the wavefront technology. This autorefractor is powerful and we were able to create something so powerful while also figuring out a way to shrink down the technology to something ten times smaller than anything else in the market. We can provide a customized prescription for everyone beyond sphere cylinder. We want to give people vision even better than 20/20. The future is using a device like this to match the digital technology on the lens manufacturing side and then ensuring that everyone has an exact pair of glasses which meet their specific needs. For a normal person like you and I, 20/20 vision is probably okay. But when you’re looking at a more high-end market, maybe people would want to pay extra money to have better than 20/20 vision. From military professionals to sports leagues, there are so many markets where having vision better that 20/20 is really important.

“So we did a number of clinical studies. Can you talk a little about our latest one on Major League Baseball players with Dr. Laby?”
So this clinical study was conducted last year during the spring training season with 5 MLB teams and over 600 players. We discovered that they have 20/12 vision much higher than the average person and even approaching levels or “superhuman eyesight.” In baseball, any refractive error is detrimental. Players need to be able to capitalize on any potential advantage, such as correction of refractive errors. We found that with our refraction technology, MLB players have 0.22 diopter sphere and less than 1/10 diopter cylinder. Most eyeglasses typically won’t even correct that. So I was blown away at how our technology can detect something that a normal lens wouldn’t correct.

“Can you also talk about the pediatric study? With the back-to-school season coming up, lots of kids need glasses to see the board at school. What did you find interesting about this study?”
With a pediatric market, the most important thing is accommodation. So the question with this market is how do you develop a technology with truly relaxing accommodation power? Well, that’s exactly what we did. Our autorefractor relaxes the patient through the ease of its technology. And that combined with the accuracy of the wavefront technology creates a tool that can successfully detect young people’s refractive error.

As for the peer reviewed clinical study, we conducted on healthy adults ages 18 to 35, we found similar results in accuracy. We were able to successfully prove the correlation between our device results and manifest refraction result and were able to detect a correlation coefficient of 0.97. That’s an insanely good number and we’re truly very proud of this technology. Not to mention this was done 3 years ago with our original technology which has only improved since then.

“Were there any case studies that surprised you or were there any findings in the clinical studies that you weren’t expecting?”
I would have to say the Major League Baseball study. I wouldn’t necessarily say I was surprised, but I was definitely amazed by it. We shipped a device to Florida and someone who had never used our technology was able to get highly accurate results. It’s truly an indication of the device’s impressive user experience. Any doctor, or even any person for that matter, can pick this device up and get results similar to those in our clinical studies.

“So let’s talk a little bit about doctors. How do you see this product fitting into their practice, either as a complement or supplement piece of equipment?”
Well for doctors efficiency is key. They see tons of patients and every minute they’re able to save can translate to an economic benefit. With technology like this, they can do an exam right in the waiting room in just minutes without even needing to bring the patient into another room. Additionally, the technology is mobile so you can bring it anywhere. The device itself weighs about 1 lb. There is some added weight because of the stand, but you can also buy a commercial tripod to place the device onto. It’s very easy to move around and with this technology, you can essentially carry your practice with you in a bag. That was unimaginable even 5 years ago. What’s also great about this is that doctors with busy practices who have patients coming in for different needs are now able to direct patients based upon those needs in a more efficient way. It’s sort of like triaging. If they only require a vision exam, the doctor can now do that quickly and devote more time to patients in need of more comprehensive care. This autorefractor allows doctors to be the champion of efficiency through optimizing their workflow by sending patients to different areas of specialties based on their needs.

“How do you see doctors using our device and/or getting involved in telemedicine?”
There are multiple different scenarios on how doctors could get involved in telemedicine. For the doctor who travels a lot but wants to be able to keep the clinic or practice open while he’s traveling, he’s now able to do that. It really depends on how much they want to get involved and the extent at which they want to incorporate telemedicine into their practice. I’ve seen doctors wanting to help other optical retail locations in their free time that are now able to do that. Regardless of their desired level of involvement, telemedicine allows for a lot more flexibility.

“Do you have any advice for new doctors or optometrists as it related to technology?”
We’re in an age of cutting edge technology with a lot of new advances constantly occurring. My advice would be to immerse yourself in learning about these technologies in person to get a sense of what they’re all about. These new technologies might become the status quo and you definitely don’t want to be left behind. You want to acquire all the knowledge – even the knowledge beyond the schools – to incorporate into your practice. We’ll be at Vision Expo West in Las Vegas, September 13-16, 2017 if you want to come see the technology in person, go through the exam, and just play around with it.

“Let’s go through how quick the refraction process takes.”
You can see (video below) once the eye appears in front of the camera, the software is automatically triggering the camera to take a picture without even touching the screen. It takes 3 images per eye and the results appear right away, even faster than the previous generation. The device really is hands-free. This sort of experience was not available before in the medical device industry. So we decided to combine an easy to use consumer experience with a very sophisticated medical device. It’s something that we’re really proud of.


“Since launching the product, what was your biggest ‘Aha’ moment?”
Generally speaking, it was probably just with the learning process of it all. We launched our first product 3 years ago and I thought to myself, “Okay that’s it! I figured it out, this is the ending product.” But I quickly realized that it’s a process that involves a lot of learning. People give you suggestions, you get feedback from the market, and you then make the product better. I didn’t initially realize how much the product would develop.

“What would you have done differently?”
I would have to say I would’ve had better communication from day one. I’m not a medical doctor and I don’t think we communicated with optometrists and ophthalmologists enough. When we entered this industry, we had a mission as tech guys to solve a real problem. So I would have had better communication with ODs and MDs to tell them what we want to accomplish. It’s something that really would’ve helped us along the way.

An advanced autorefractor, and specifically the SVOne, has substantially helped grow optometry practices and optical retail stores. Its portability, affordability, and clinically proven accuracy makes the SVOne an excellent addition to any practice or retail operation. If you’re interested in learning more about the SVOne autorefractor, request a demo for a more in-depth understanding of how the device works.

Get a new autorefractor - Smart Vision Labs

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svone autorefractor by Smart Vision Labs

Shopping for an Autorefractor?

Tips on How to Select an Autorefractor

SVOne Autorefractor from Smart Vision LabsWhen it comes to conducting vision exams, and specifically measuring just how much your patients’ eyes need to be corrected, an autorefractor is the optimal tool to measure the refractive error of the eye. There are many autorefractors on the market to choose from. But when considering the different purchasing options, it’s vital to decide which direction you would like to take your optometry practice and consider which attributes of an autorefractor allow you to move in that direction. The measurements taken by all autorefractors can translate into a prescription for eyeglasses or for contact lenses. But the SVOne autorefractor has a unique set of features that differ from the average desktop autorefractor. And why settle for just average?

The technology of the SVOne is a Shack-Hartmann wavefront sensor, allowing you to view spotfield readout in real time. These types of sensors have the ability to measure a very wide range or local wavefront inclinations. This level of wavefront distortion is not typically accessible through other technologies. This is not your average autorefractor.

Physically speaking, the SVOne autorefractor can either be handheld or mounted on a height-adjustable stand. And for all you budding photographers/videographers, it is even compatible with a commercially available tripod. The SVOne autorefractor is perfect for the mobile optometry practice, or even for convenient mobility around an optical store or optometry practice. Its versatility makes it an excellent purchase.

The device itself has hands-free alignment, driven by a machine learning algorithm. The patient no longer needs to be seated with their chin in a stabilizing chin rest, as the machine will stabilize the image itself. Those clunky autorefractors in the dark optometrist’s office are pretty outdated. Don’t be afraid to try the new, innovative technologies. All the “cool kids” are doing it.

The SVOne weighs approximately 1 lb (454 g). Its lightweight feature makes it highly portable for the mobile optometry practice. It’s also perfect for that person who might skip the gym visit a little too often – even they will have no problem carrying this portable autorefractor.

Remember the days where all medical records were stored in file cabinets? Well, I don’t, I was barely alive for those days. But anyways, they are now long gone. This autorefractor has the ability to store up to 4,000 saved refractions right on the device and has unlimited refraction data storage in the cloud. And don’t worry about privacy and security, Smart Vision Labs is HIPAA compliant.

If you’re still the old-fashioned “I like a hard-copy of my records” kind of person, we have an option for you too. The SVOne autorefractor can connect to any AirPlay printer to print exam results. We have iPhone technologies to thank for that one.

In case you haven’t noticed, we’re all about speed and convenience. The vision exam itself is remarkably quick. And specifically, the data acquisition time is about 3 seconds per eye, and the autorefractor measures and averages 3 readings per eye. The results come in, figuratively speaking, in a blink of an eye.

And if you’re still skeptical, we have three clinical studies to prove the SVOne autorefractor accuracy. With the help of the SUNY College of Optometry and the Sports and Performance Vision Center, we were able to test the accuracy of this autorefractor in a population of MLB players, a general adult population, and a pediatric population. All three clinical studies concluded that the SVOne is well-equipped to measure a refractive index.

Lastly, if we still haven’t convinced you yet, we’ll play into your potential patriotic nature. All of our autorefractors are manufactured in the United States. So when returning to your optometry or retail operation with an SVOne, you can pride yourself on knowing that you gave your business to manufacturers on your very own soil.

If these attributes are anything your optical store or optometry practice is looking for in an autorefractor, request a demo of the SVOne to further see why this device is the perfect option for you.

Demo the SVOne Autorefractor
Issy Bonebrake is a born-again New Yorker living down in the Village. She considers herself to be a self-proclaimed, cautiously optimistic futurist. As a classic rock aficionado, she enjoys binge watching rockumentaries from the coziness of her less than 500 square footage apartment. 

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