Bucknell researchers look to improve vision in Guatemala
LEWISBURG, Pa. — The road to the motel in San Pedro, Guatemala, was narrow and steep — about 5 feet wider than the bus — and descending on a 20-degree incline, as Associate Professor of Mechanical Engineering Charles Kim recalls it.
The bus driver had mastered the hairpin turns on the mountain roads between Guatemala City and the lakeside village of San Pedro. But the last stretch of the 3 1/2-hour trip seemed a formidable final obstacle, especially in the pouring rain — with no guardrails.
Still, the passengers had little idea that day in August 2011 of what challenges the bus driver had overcome to get them to their destination. They would find out later that he had done so without the benefit of eyeglasses and with significant vision impairment.
The bus driver is among many in Guatemala who do not have proper vision care both because of expense and the scarce availability of optometry services. Kim and Associate Professor of Management Jamie Hendry, along with a number of student researchers, are working to change that. They are developing tools and a sustainable business plan to diagnose vision deficiencies and manufacture and distribute eyeglasses in remote villages.
The project was initiated by Bucknell alumnus Adam Andersen, a 2010 graduate in mechanical engineering and management who completed his master’s in mechanical engineering in 2012. He recruited Kim and Hendry to help after reading Paul Polak’s book, Out of Poverty, in which the author asserts that uncorrected vision is a crippling factor in overcoming poverty. Other groups have pursued the idea, but cost, distribution, local involvement, and sustainability are continuing challenges.
The right fit
As part of the project, Kim and mechanical engineering students Tyler Campbell, Greg Epremian, and Andy Klein perfected a design for a diagnostic tool, which they jokingly dubbed the “pirate telescope.” It is made with two pieces of PVC piping that slide into one another and enables anyone to diagnose vision deficiencies within .5 diopter, the common measure used by optometrists, Kim said. Kim and his students also previously designed a lens edger, which includes a grinding wheel and round template lens — much like a key cutter — to enable a local entrepreneur to make eyeglasses for about $5 rather than the standard $300 to $400.
During the 2011 trip, the Bucknell group traveled with a cohort from Christ Wesleyan Church in Milton, including Lewisburg optometrist Robert Lipski. Lipski examined dozens of children and adults, including the bus driver. In most cases, the optometrist found that even those who wore eyeglasses had the wrong prescription. The Bucknell and Christ Wesleyan group took several suitcases full of donated eyeglasses to Guatemala in the hope of matching villagers with their proper prescriptions, Kim said, but that method proved a bit like finding a needle in a haystack.
“Bob examined the bus driver, and he couldn’t see anything,” Kim recalled. “Bob searched in his suitcase full of donated glasses and fortunately was able to find a pair with the right prescription.”
The project has taken some unexpected turns, in part after the revelation that children even in remote parts of Guatemala are concerned about style.
“During our trip in 2011, Andy, Adam and I designed a lens cutter but found we could not cut oblong shapes,” Kim said. “We simplified the machine so it could cut circular-shaped lenses, and it worked well. But we found that no one wanted to wear circular-shaped lenses.”
The group also realized they needed to involve the community and get buy-in for the effort, rather than trying to determine what was best for the villagers, Hendry said.
“If we are going to create a sustainable business, it is essential that this is a local organization,” Hendry said. “Local folks need to get involved in designing and eventually running the business. And once it’s up and running, we go away, and they handle it on their own.”
Hendry, meanwhile, has been working with management students to determine appropriate business models. The management group is considering a model comprising three workers: one to diagnose and fit the eyeglasses; one to cut lenses and assemble them with frames: and one to manage the office, inventory, maintenance and supplier relations.
A continuing challenge is the cost of transportation.
“Most of the optometry services are in Guatemala City,” Hendry said. “Just the expense of traveling is prohibitive for most people. The town where we would like to set up the business is on a lake. There are little villages all around the lake, but if you need to get to one side or the other, it costs a week’s wages.”
One idea for reducing transportation costs is to travel with local churches and schools to offer optometric services periodically in remote areas, Hendry said.
This winter, Kim and Hendry plan to travel to Guatemala again with students. The management students will be researching legal issues and surveying optometry students about their interest in serving in rural areas. The Bucknell group also will pursue partnerships with suppliers and other churches and schools and search for space for a warehouse and workshop. The engineering students will continue to work on creating optometric devices that can be constructed using locally available materials and local labor and equipment and that will produce eyewear that is both functional and aesthetically pleasing.
Over time, the group hopes to increase the sustainability of the operation. The team will investigate, for example, whether scraps produced from lens cutting may be reused or recycled and whether frames can be manufactured locally.
Despite the challenges, Hendry said, the project is rewarding. She recalled delivering a new pair of glasses to a girl at an elementary school during a trip in March. Lipski, the Lewisburg optometrist, had examined the girl’s eyes the previous August and discovered the glasses she had were the wrong prescription. So he made new glasses for her and sent them back to Guatemala with the Bucknell team.
“This girl was wearing a pair of glasses with a cord around her neck. She tried on the new pair of glasses and found she could see so much more, so she ripped off the older pair. That really brought it home for me, how important it is for these people to get the eye care they really need.”
Hendry and Kim eventually hope to expand the project by replicating it in other locations in the developing world, such as Nicaragua, they said.
Article by Bucknell’s Division of Communications
By Julia Ferrante
For Original Article: Click here.
We recently met with Bob Lipski (and his wife Sherri for a brief moment) to learn more about suppliers, start up costs, and the physical space required for the business. As always, Bob was incredibly helpful!
What we learned:
- Optical infinity occurs when the patient is 20 feet from the item they are focused on,; this is where diagnosis is most accurate. According to Bob, using mirrors to create 20 feet does not affect the accuracy of finding a prescription. Using two mirrors works well to create 20 feet.
- Do supplies (lenses, frames) need to be stored in a special way? No. The material (especially polycarbonate) is hardy.
- With regard to what lenses we should order: Other than using the distribution of lenses he provided us, he didn’t have much guidance as to how much to order, because he cannot predict the demand. He said that even if he did know what the demand was going to be like, need for prescriptions is so random…Charles believes we’re just going to have to track our usage well upon starting the business and learn from trial and error. Bob said our distribution will differ from his (that he uses in his shop) because there are more astigmatic patients in Guatemala (need to order cylindric lenses).
- I asked Bob about what sizes to stock for frames. He said that adults use 52,54,56 mm sizes. They all look the same, but fit differently on the patients once they’re tried on. For adolescents, he recommends 42, 44, 46mm.
- Our real breakthrough was our discussion of potential suppliers. Bob called his supplier, who said that Indo would be a good place for us to start. The organization operates all over the developing world to supply optometry supplies and equipment. Charles added that we should check out Esselor, a humanitarian organization that has funded various eye care projects such as Aravind.
- Charles posed a good question. If we are legally required to have a diagnosis from a licensed professional in Guatemala (as we think we are), how do other businesses and charities function legally diagnosing via employees who are not licensed in optometry? We need to do some digging here. I have a list of organizations doing eye care in the developing world from Adam Anderson’s ’12 masters thesis.
- Charles and Patience asked Bob some questions about the engineering they are currently doing. Their goal is to diagnose astigmatism more effectively. They asked for his input on various technologies. He stressed that giving clear instructions is key to an accurate diagnosis (Ex. say, ” does this help?” rather than “is this clear?”).
So I spent most of the day at Dr. Lipski’s office observing the way he handles his patients
While I am waiting for IRB approval, I have a few things to get in order before testing actually starts. I need to turn the general testing procedure into specific steps (like write out a formal step by step procedure for each subject), make the tools (cut the lenses), and recruit for the study.
Yesterday and today I focused on making the tools. The problem I have come across is how to cut the lenses spherically. I have done all that I could to avoid using the lens grinder made by Paden simply because he isn’t here to explain what to do and I’ve never used a router before. First I went to the staff at the PDL; they suggested a multitude of different things all of which involve their assistance. The catch is that they cannot help until next week…One of them suggested that I use the laser cutter which I thought was impossible because the lenses are polycarbonate. However, they said I could if I wrapped the lens in tape; one of the staff came up and showed me a way to do this. However, the method didn’t work as I was left with a charred and smelly mess. Theoretically (he explained), it should have worked but our laser cutter is in such bad shape that it failed miserably.
I need to make these tools now and the only option left (that I see) is to use the lens grinder. Thus I spent the past couple days ‘messing around’ with it and learning to use the device. The first couple of lenses were disastrous as I was more afraid of using it than anything else; it didn’t help that I was going off of watching Paden use it months ago. I made a ton of mistakes like trying to cut the lens in the wrong direction; the device jerked badly and I quickly adjusted what I was doing. After cutting a few lenses, I can say I have improved significantly. Once I get confident enough at using the device (probably tomorrow – that’s the goal), I will cut the new spherical lenses from Dr. Lipski. I only have one set of lenses currently due to ordering mis-communication but that’s only a temporary set-back.
Keeping this in mind (that I want to finish the pinwheel device first and in the next couple days- I’m already behind what I originally planned), I realized I had to come up with a modified procedure to cut the lenses. I used the laser cutter to make a template for just like Paden did for the spectacle shaped lenses. I cut a hole in the middle (with the laser cutter) so I could properly center the adhesive pad on the metal block (the one that holds the lens to be cut and the template). I used the laser cutter to make something that made the placement of another adhesive pad in the center of the lens to be cut. This is the tricky step because the lens is obviously curved and finding the center is critical to the placement of the cut. I took a couple of pictures to show my simple method:
I filled out the IRB application completely and the essay answers can be found in the drop box- go to Approtech then IRB and 2013 application. All of the documentation that goes with the application is there. I know editions are necessary but this is progress thus far. Whenever you get the chance, take a look at it even if it’s when you get back. I still haven’t figured out which targets I am going to end up using; I did make a colored astygmatism wheel (see below- it is not to scale but you get the idea). It works fairly well but I still prefer the standard bi-chrome chart (but that still leaves the problem with astygmatic patients). Additionally, for the other target option, I am thinking we stick with the astygmatism wheel (plain) and then have the bi-chrome test chart just next to it that way we can use it for refinement purposes right then and there without having to change targets. That way we also get a better gauge if the bi-chrome test has any measurable effect as compared to past results.
As a random side note, after playing with the tools and simulating what it would be like to be a patient and found out that my tool eyepiece is actually too large. When I tried to place it properly against my eye, I couldn’t because the tool hit my nose. Thus I have to make new ones that are smaller so that the patient can center the eyepiece so that they see through the center of the lenses (which is not really possible with the current prototype unless you hold it away from your face a bit- but this is a source of error that needs to be minimized for optimal potential according to Dr. Lipski).
Another update for the week is that the lenses finally arrived at Dr. Lipski’s office (however I did not get the email until 1:30 which was after he closed for the day). Thus once I get back, I will be able to make the actual diagnostic tools. I want to re-size them though so that they do not hit the nose of the patient, especially before I cut the lenses.
When I come back, I need to make a ‘formal’ set of procedures and do a mini-trial run with perhaps some teammates to find out what works and what doesn’t (after the tools are ready to go). I have the bulleted list in another post which describes what I want to do, however I have not come up with instructions to give the subjects or figured out the where, when, who…etc. which will all need to be planned once the IRB application is accepted (I did not submit it yet simply because I want Professor Kim’s help with revisions and suggestions.
In summary, this week was mostly about figuring out a testing methodology and getting closer to the testing process. We now know that we want to test 2 different targets and all 3 devices for a total of 6 tests per subject. I tried out multiple targets ( see second picture) to see which combinations seem to work more effectively than others and I found that the duo-chrome is actually very helpful because there is the comparison factor between the letters with different background colors instead of almost blindly guessing with the plain clock from before. I thought I was going to be able to see Dr. Lipski again this week but circumstances did not allow for another meeting.
Colored Astygmatic clock- we can ask patients if they have a preference between the different letters of if there is a set of letters or lines which are more distinct than the others. In theory I feel like this could work but I want to ask Bob’s opinion first.
These were a few of the targets that were moderately successful- the one in the bottom left has a grid and a bulls-eye pattern that I expected better results from meaning the point of clarity would be easier to recognize, however this was not the case. Additionally, for an astygmatic patient, this type of grid could look incredibly skewed and be difficult to use; thus I stuck with the clocks. In the upper left, there are two rings with varying thicknesses and ‘hole’ sizes that I thought would look more like a ring when unfocused and then when in focus the gaps would be distinct. Again there was a problem recognizing that initial point but I did find that the thicker lines with smaller gaps gave me less trouble than the opposite conditions.
One thing that I did by accident is that I used one target like the plain circle targets and then then moved to scope to focus on the duo-chrome targets, made the adjustments based on color preference, and then read the prescription. This yielded much more consistent results than using the targets by themselves (minus the colored clock with letters- bottom left).
3 Tools, 2 Targets
Device1 : Pirate Scope
Device3: Whale Bones
- Plain astigmatic clock with duo-chrome refinement in corner of chart
- Colored astigmatic clock
- Grid-like target?
1. “This is the tool you will use to diagnose your prescription. While I move the tool, you will be asked to identify when the target image becomes most “clear.” Clear should be when the image is sharp and well-defined. Be sure to differentiate between size and clarity. Focus on the boldness and blackness of the lines. At the clear point, the letters on the target with red backgrounds will be equally black and bold as those with green backgrounds. ” Please play with the tool, resting the fat end on your RIGHT brow-bone (the bone under your eyebrow), moving it in and out to determine for yourself what clear means.”
2. Let subject use tool for a minute or 2.
3. “To determine your prescription, I will start with the tube in the fully extended position. Rest the fat end of the tube on your RIGHT brow-bone. I will slide the inner tube toward your eye until the image becomes clear with the black lines well defined. Please indicate the initial clear point. Indicate if I go past the point of clarity. The image will get smaller and darker. I will then begin the process again. .”
4. Have subject use tool until 3 results are given for RIGHT EYE.
5. Have subject use tool until 3 results are given for LEFT EYE.
******The above procedures are taken and slightly modified from the senior design team’s instructions used in their experiments
- Subject uses tool as it rests on stand to recognize ‘clear point’ which is when the target is in focus- all the lines are defined
- Experimenter takes control of moving scope
- The scope’s starting position is fully extended
- The experimenter asks the subject to recognize the point at which the lines on the target reach the clear point as the experimenter slowly retracts the scope
- When the clear point is reached, the experimenter stops moving the scope and makes note of the diopter setting and asks the subject which letters look bolder and more distinct: those with red backgrounds or those with green backgrounds
- If the subject replies red: retract the scope by half a diopter and repeat the question, if green: extend the scope by half a diopter
- Repeat this process until the subject indicates that there is no difference, or no preference between the letters- make sure to emphasize the boldness and blackness of the letters and not the brightness of the backgrounds
- The final diopter measurement given by the tool is recorded
- This process is done first for the right eye and then for the left eye
- This procedure is repeated for both targets
Give the subjects 1 -2 minutes for their eyes to readjust before moving on to the next tool
- Subject once again will look for the point of clarity
- Subject holds handle of tool in the hand corresponding to the eye being examined with the tool, their thumb on the back part of the handle- the subject rests their thumb against their cheek with the center of the eyepiece aligned with the center of their eye- this extra distance is needed between the eye and tool to prevent the wheels from hitting the subject’s nose (as I found out from playing with it)
- Experimenter rotates the tool to +5 diopter setting (+2, +3, and blank for each wheel) and rotates the wheels down by increments of 1 diopter until the patient indicates the target characters are recognizable (not necessarily sharp but they see the letters)
- Experimenter continues to decrease diopter setting by increments of 0.5 diopters until the point of clarity is achieved
- The experimenter then uses the third wheel with the +0.5 and -0.5 diopter lenses to find the combination which yields the clearest target by quick transitions between diopter settings
- Remember: clarity means the lines of the target are boldest and sharpest
- The subject is then asked which letters look blacker or sharper- the letters with green or red backgrounds- if the answer is green then rotate to the + 0.5 diopter
- Use the -0.5 diopter if the answer is red
- The key is to get to a lens combination in which there is no preference between the letters of different backgrounds
- First prescription is obtained for right then left eye
- Procedure is repeated for both targets
Give the subject 1-2 minutes to readjust their eyes before moving on to the next tool
Whale Bone Design
- Subject once again will look for the point of clarity
- Subject holds handle of tool in the hand corresponding to the eye being examined with the tool, tool’s eyepiece base should be held comfortably against the face so that the center of the lenses are centered with the tool
- Experimenter slides in the +3, +2, and +1 lenses to begin and decreases the total lens prescription by increments of 1 diopter until the subject indicates that the target characters are distinguishable (not necessarily sharp but they see the letters are there)
- Experimenter continues to decrease diopter setting by increments of 0.5 diopters until the point of clarity is achieved
- The experimenter then uses the third slot for refinement by alternating the +0.5, -0.5, plano and no lenses to find the combination that yields the clearest target for the patient
- Try to make quick transitions between prescriptions
- Remember: clarity means the lines of the target are boldest and sharpest
- The subject is asked which letters look blacker or sharper on the target- the letters with green or red backgrounds- if the answer is green then add another+ 0.5 diopter lens
- add the -0.5 diopter if the answer is red
- The key is to get to a lens combination in which there is no preference between the letters of different background
- First prescription for right eye is recorded followed by left
- procedure is repeated for both targets
For all 6 tests, the subject will cover the eye not being tested with their hand and asked to relax it. Additionally, these tests will be conducted under dimmed lighting. Once patient finishes these tests, they are sent to Dr. Bob Lipski’s station where he will used his preferred method of diagnosis to find the proper prescription of each subject. The measurements taken for each tool and target will be compared with Dr. Lipski’s assessment to find the tool and target which yields the best correlation. The goal is to be within 0.5 diopters of the proper prescription. Total testing time per subject will be approximately 20 minutes.
So yesterday I had the opportunity to visit Dr. Bob Lipski’s office to meet, ask questions, and learn retinoscopy directly from him. To say I learned a lot is a complete understatement. I had no idea what I was expecting from the visit only that I had key questions to ask. What surprised me most was how much better I feel with the material I have been reading about because Dr. Lipski was so hands on in his approach. Throughout the session I was able to ask my questions and we got more in depth than I expected. One of the most important parts of my visit is that I have a much better appreciation for what the patients who we are attempting to help are going through. I asked Dr. Lipski to put me in the patient’s seat. He put different lenses in front of my eyes and had me try to read the chart on the wall. He did this for spherical and cylindrical lenses so i could better understand astymatism. He also then showed me what it looks like as he cycles through lenses which get closer to clear and crisp vision. One thing that shocked me is that Dr. Lipski indicated that he did not like using the phoropter; he said that it was just a fancy tool that apparently causes him to under-minus people a lot because of the distance between the patient’s eye and the lenses in the phoropter. I think this is an important factor to consider with our diagnostic tool. I asked him to show me what kind of difference such a distance makes just to get an idea of the magnitude of the problem. He took two lenses in front of my eyes and told me to focus on the letters on the chart. He then proceeded to move one of those lenses away from my eye towards the screen and I watched the image get blurrier until I could barely make out a blob of a letter. Dr. Lipski said that this sort of error is worse for higher powered lenses like and 4 diopters in magnitude and above. This is good news for the pinwheel and whale-bone design as the maximum lens power is a magnitude of 3 diopters. I got to see that even with 6 inches between lenses of 3 diopter magnitude, the distance that that difference made was not that extreme. The scenario is when the lenses are stack one on top of the other; considering that the pinwheel causes a separation from one lens to another by a small amount (maybe .5 cm at most) and the lens powers are small in magnitude, I am becoming more confident in the potential of the pinwheel. It is important however that we make sure that with that device the patient has the handle part and holder on their face or very close to it to minimize the error caused by the distance between the lens and the eye.
Another thing I questioned Dr. Lipski about is the Duo-Chrome test as we are looking into it as a possible option for diagnosis. Apparently he uses this test quite frequently for his patients as a means of refinement of his diagnosis. He first uses the phoropter to get a general idea of a person’ s prescription, then uses retinoscopy and finally the duo-chrome test to refine the whole diagnosis. The test entails asking the patient to look at a target which has a solid red background on the left and green on the right with bold black letters centered across the middle. The patient is asked which black letters (which side) do they prefer based on how bold, clear, black, and bold the letters were. I paid attention to his diction here as from my readings I knew that the duo-chrome test results can be thrown off if a patient chooses a side simply because the background is brighter. I brought his attention to what he had said and he emphasized the importance of giving clear directions so that patients know what to look for. He said that this is especially important for patients in Guatemala because of the language barrier and the fact that some of the people have never had any sort of eye examination. This surprises me a lot because of the doubt from a couple sources about the duo-chrome test and its reliability. I asked Dr. Lipski what he thought of using the test as a more general form of diagnosis and he said that it was made simply for refinements. He went on to explain that if the eyesight is bad enough and a patient cannot even make out the letters on the target; when this happens both sides look equally atrocious and you would be left blind guessing. Considering that the pirate scope can give a general idea of prescription, perhaps we could use the duo-chrome test for refinement purposes for our own diagnostic procedure. I was more skeptical of the test itself because it is strange to thing that you can see the black letters more clearly based upon a color background but Dr. Lipski had me experience this first-hand with trial lenses. There was defintely a distinct difference between the letters on the green versus red background. He was insistent on saying that green is ok for a patient to prefer, red is bad knews, but no preference is exactly what you want to hear. From this, I think it is worth the effort to make some sort of target to use with the pirate scope, scaled correctly, to see what kind of difference it will make in our accuracy with that device.
Retinoscopy 101 Experience
One of the purposes of me going to see Dr. Lipski was to learn to perform retinoscopy so that I can verify results once testing of the new devices and/or new processes is begun. Plus it would be incredibly beneficial down in Guatemala for me to have that skill. Before the visit, I had done extensive research on retinoscopy and the process of diagnosis; however, reading and doing simulators does not really do justice to the challenges of performing it in person with a patient.
We started off easy as Dr. Lipski had me first use a model eye to get a better picture of how retinoscopy actually worked within the eye. He had me look at a the conditions of a normal eye where the light focuses perfectly on the retina after passing through the lens of the eye. He then selected extreme myopic and then hyperopic lenses so I could learn to recognize with and against motion with the retinoscope. The model eye was extremely large and the refractive abilities of the lenses so strong than it was not hard to pick up the patterns I was supposed to see. He then proceeded to show me what astygmatism looked like with the retinoscope by putting a cylindrical lens into the model. Using the streak retinoscope’s rotational cylinder in the base, I was able to orient the light streak along the two astygmatic axes. Dr. Lipski explained that the goal of retinoscopy is to neutralize the refractive error of these axes which are almost always perpendicular.
When they are not, you get a scissoring effect, however he assured me that it is rare to occur. If the scissoring effect is observed then glasses cannot be used to fix that patient’s eyes. I asked Dr. Lipski about how common astygmatism was and he answered that almost everyone has some form. He said that in Guatemala, astygmatism is a huge problem and that most of them have ‘with the rule’ astygmatism meaning the axis is 180 degrees. Conversely ‘against the rule astygmatism’ is at 90 degrees but is less common. I then proceeded to ask about how to recognize cataracts and other abnormalities in the eye while performing retinoscopy and how to get around them. By using this one plastic lens and a marker on the model eye, he simulated the conditions of cataracts and had me pass the retinoscope over it to see how ‘funky’ it the reflex appeared. Dr. Lipski laughed a little and said that there was no magic to it but that you simply do the best that you can to see around or through the issues. You cannot always help a patient and when that happens you simply have to move on to those that you can.
Anyways, the purpose of my visit was to learn spherical retinoscopy not diagnose astygmatism. He had me pay attention to the speed, brightness, direction, and width of the reflex as the retinoscope is flashed across the eye. Just like my readings indicated, Dr. Lipski explained that it was easier to look for width motion first and then move on from there by adding more positive lenses. When the reflex is slower and dimmer, the refraction is far from neutralization. Thus the goal is to cycle through lenses until the speed increases (to infinity), you have slight width motion, the line of the reflex is at its peak (as in no line, just illumination of everything), and the reflex was at it’s brightest. This is when you recognize the correct prescription. After doing a couple diagnoses with the model eye, he made it much more challenging.
Next Dr. Lispki took a seat in the patients chair and use the retinoscope on his eyes so that I could develop the proper techniques. He said that one of the most important things is alignment; the beam of the retinoscope needs to go straight through a patients pupil. Dr. Lipsky had me pivot around different ways and I saw how easy it is to make a mistake in recognizing the reflex properly if you are not properly centered. He then instructed me on working distance and how with spherical prescriptions, it is of the utmost importance to subtract the working distance at the end. From my previous research, I knew that this is because you are looking for a person’s prescription for focusing at infinity and not at the distance you make the diagnosis thus it must be subtracted. The working distance is usually 1.5 diopters but he said that since I was shorter, I could be all the way to the 2 diopter range but was not entirely sure. Anyways, he allowed me to experiment with the retinoscope to see the actual reflex and to get more used to using the tool. As I was doing this, Dr. Lipski pointed out that I had the tendency to lean in too much which affects the working distance, a common mistake for a beginner to make; thus I adjusted and continued.
While I was moving and rotating the beam of the retinoscope across his eye, I noticed that the streak and the reflex did not always line up. From my research, I knew that this meant he had astygmatism so I inquired about it once I found the proper axes; he was surprised I was able to detect it and find the axis because his prescription is so light and the astygmatism so minor. As expected, retinoscopy on an actual person is much more challenging; the reflex is smaller to see, you have to balance holding the lens in front of the patient’s eyes without hitting them in the face or dropping it too low, you have to keep the retinoscope moving at a moderate pace so you don’t completely constrict their pupil, maintain your alignment with their eye and the light of the retinoscope, not to mention getting past the challenges caused by imperfections in the eye…Needless to say there is a lot going on all at the same time. However, after a little bit of toying around, Dr. Lispki said that he wanted me to diagnose his eyes but only focus on the spherical aspect.
As I worked through the process, I told him everything that I observed and he walked me through the process. It was challenging but a lot of fun. I was able to see the width and against motion as I cycled through the different lenses until I found neutralization. This point was not as clear and definitive as I had anticipated, however it could simple be from inexperience. Dr. Lipski then proceeded to put random contacts into his eye and repeat the process. The first contact I had a bit of trouble. After explaining my difficulties and what I was observing, Dr. Lipski said it was probably because he was staring too long and the contact became too dry. He said that dry eye is a common problem to run into and it can make diagnosis hard. He said that it is important to remind patients to blink and relax. From this he transitioned into another common problem encountered during retinoscopy; that is that patients need to focus on something distant behind the diagnostician. Patient (especially children) try to look directly into the light of the retinoscope. The second this happens, the diagnostic becomes almost impossible and then your working distance is messed up. Overall: don’t let it happen. While I was diagnosing his eyes, Dr. Lipski accidentally did this to me and I watched the once bright reflex turn almost orange and disfigured. The second that his gazed shifted behind me again, all returned to normal.
After this, I was able to diagnose his eyes with and match the prescription of the contacts he had put in his eye (this was the second random one). Dr. Lipski said that as long as one gets within 0.5 diopters of the ‘actual’ refractive error, then you have done your job. He said that this is a reasonable amount of error for our purposes based upon the needs of the people in the underdeveloped areas. I asked him at what refractive error does a person truly need glasses. His answer: a normal person can function with a refractive error of up to roughly 1 diopter.
Overall, this was an awesome visit and I would be glad to take advantage of his invitation to return and see how he handles patients. I want to listen to the kinds of diction and such so that I can get a better gauge of what is effective and correct in the diagnostic procedure and then mimic it for our own. Plus he told me I could work with actual patients and I can work on astygmatism because I was able to pick up the spherical quickly (or at least that is what Dr. Lipski indicated).
1. wait for lenses to come in (Dr. Lipski ordered them)
2. get more familiar with retinoscopy
3. make a properly scaled duo-chrome chart…then test
4. put together the prototypes and test them out
5. explore the cross-hatch target idea- Dr. Lipski sort of liked this one but I have a feeling that the duo-chrome is a better option if it is one at all
6. evaluate what direction is working best and test some more
This is a great source for all sorts of diagnostics and optometry in general. I was more focused on the section which explains the theories and practice of the duo-chrome test as we are looking into it for a possible change in our own diagnostic procedures.
While last week was about hand prototyping in the PDL with raw materials, the most important highlights of this week were learning to prototype with the laser cutter and I even got a chance to learn about the 3D printer.
I had absolutely zero experience with these apparatuses until this week and am proud of the learning curve that took place in such a short period of time. What surprised me was how intricate these machines were to set up and how one little error can actually do a lot of damage. I probably learned more of what not to do than what to do, but both are equally valuable.
From a design standpoint, I became more familiar with some features in SolidWorks that I was unaware of after talking to Sam. Additionally, I learned how to link different aspects of a design so that it is more efficient to make changes; I figured this one out the hard way after having to break apart the whale-bone design to make in the 3D printer simply because of the structures that I wanted made. This is because if I had tried to print the design as one single piece, the prototype would have turned out wrong as the piece was asymmetrical and would have printed as a warped model. As a result, I made a new design with snap in parts so that I could assemble them into what I wanted. This part of my week is where I learned about the entire design process. For example, I learned about tolerances; this important aspect is something I completely forgot so when I tried to piece my model together it didn’t work. I then proceeded to use clamp a drill-bit to the table and turned the parts by hand to expand the holes to the proper size (I didn’t want to waste material plus I prefer to work with my hands anyways) so I wouldn’t crack the plastic. Although I ‘messed’ up making this model because rings were thicker than I had planned (measurement error), I made a new one using the laser cutter anyways and screwed the parts together. I am overall unhappy with how the ‘whale-bone’ design is coming along and may manipulate it around more next week.
Moving on to a different design though, I finally assembled the pin-wheel type design properly. Last week I simply had the wheels rotating on a nail with hot glue. Not surprisingly it constantly fell apart so I decided to find a better way to stabilize the model. Another problem was that once all of the wheels were stacked together, the wheels stuck together which will be a problem if the whole purpose of the wheels is to allow for single step transitions for lenses. Additionally the wheels rotated too freely on the nail- they could wobble back and forth and any imbalance in the weight caused them to rotate incorrectly.
To address these problems I planned to put the wheels on a larger diameter screw with washers in between. Since I made the holes too small in the design in SolidWorks for any of the longer screws to fit, I ended up using a drill to expand the holes. However, I had to drill halfway through each side to avoid cracking the wheels because of the brittleness of the material. Anyways, I made the changes to the prototype and secured the whole thing with a bolt on the end. Although the fit was far superior and more secure (not to mention safer without a sharp end) with the screw, the problem of the wheels sticking remained. I discovered the solution to the problem accidentally by playing with the extra bolts and the wheels during my lunch break. Although the bolts are thicker thus increasing the space between the lenses that will fit into the wheel, they allow the wheels to all rotate independently. Additionally since the fit is tight, there is some resistance to the wheels spinning to that once the lenses are in place, there will be no problems with them falling to balance the weight of the lenses (what I mean by this is if there is one lens which is more massive than the others in the wheel due to the curvature and the resultant additional volume, there is no worries of the wheel rotating freely down on its own so that the most massive one can only sit on the bottom). This means that the diagnostician will not have to hold to wheels in place as they cycle through the lenses. This was my original intent for this design so I am content with the prototype thus far.
This week I also looked into other diagnostic alternatives after Professor Kim approached me with the idea of the focus-able cross hair described in a few other posts. There will be more on this to work on next week and will serve as my focus for the first part of the upcoming week.
One other thing that happened this week is that I was able to contact Dr. Bob Lipski and arranged to visit his office this week to learn retinoscopy and observe what he does/how he performs his job. I am definitely looking forward to it.