Last edited by 35oldguy; 04-30-2007 at 01:23 PM.
Can't help with the autorefractor. However here is a link to a missionary group that is using them, maybe they can help in some way.
http://eyeglasses-inventory.com/
I would reconsider use of a handheld autorefractor. They are notoriously unreliable, and I was able to use a brand new state of the art one recently, and it was worse than anything I used previously. Go desktop.
Have you read the postings on the regular forum about donating items for use in developing countries? Do you need anything else? If so, could you tell us a bit about your project under the sticky: "time to pony up."
Dave, which one did you use that was unreliable? I know the welch allyn is somewhat limited by the parameters, and sometimes with questionable reliability. But, I've heard several people like the retinomax. It can be difficult to use at times though.
As an answer to the original poster, if you had the time you could always pick up some lens bars and learn retinoscopy. !!!! Much cheaper that way, and it can actually be pretty fast when you figure it out and do it enough. I'd feel more comfortable prescribing from retinoscopy than most older autorefractors anyway. This is what we did on all the svosh trips I've ever been on, prescribed mostly from retinoscopy findings.
Welch Allyn.
Thanks for your reply. We have used a Welch-Allyn and it worked pretty well until we had to send it back to the USA for recalibration. They put new software on it and when we tried to use it the numbers were way off. That was over a year ago. Now we have had it resent back to New York for them to make it right. Desk top models get too much abuse when we do worksites and they do not give us the proper readings.
Yes I went with Vosh for years until I moved to Guatemala. Now I need another autorefracor-If anyone has a used one that they would like to give me I would appreciate it as well as the poor people we see.
Originally Posted by orangezero
I have operated a Retinomax on over 50 VOSH third world eyeglass missions, refracting over 1000 patients per trip. The team ODs are virtually all quite pleased with the printouts. They do a quick verification with retinoscopy. I highly recommend its use. At my first trip with the Retinomax, the handle batteries ran out in an hour so I came home and devised a battery/charger system to run for 8 hours on two sets of batteries that are recharged overnight. This takes the place of the charging station. I have made up about 12 of these battery/charger systems for other VOSH teams. I tried the WelchAllyn Suresight some years ago and was unhappy with the results.
thanks for the info beto.
i have heard good things about the retinomax, and may be looking in to that in the future. a bit expensive compared to less portable units, but does take up a lot less space.
How long does it take to get a reading?
did you use the keratometer function?
Orangezero inquired about speed of reading. The reading, including finding the pupil, with experience, comes up in about 15 seconds The printed output, when used, takes maybe twenty or thirty seconds. With a hard working team including two helpers, one time I challanged them and we refracted and printed out 105 refractions (patients) in 56 minutes. With normal speed and continuous work, you can comfortably refract one patient per minute - that's with one helper to staple the printout and control crowd. That speed won't work with the DR-10 batteries in the handle. Since you do not get any time on the charging station. You must use some sort of higher energy battery supply such as I devised after my first trip with the R'max. When you have a pt with quite high correction, the machine may take over a minute to find the reading. Steadiness is the key.
The OD's tell me it normally over minuses by about 0.5D. Studies on the web confirm this. It is very compact and I pack it in a small, cheap wheelie carry-on bag. No problem with customs. When doing hundreds per dy, I stand and patients stand. Much quicker to adjust instrument to the patients head, even if cocked than to get head in proper position on tabletop.
thanks again.
does it have something to tell you if its not level? Are you finding the axis readings accurate, or just relatively close?
over a minute seems like a long time to get an autorefractor reading... suppose it rarely takes that long except on the most mobile patient :)
I'm considering one for nursing home visits, etc.
Do you have any schematics for this battery pack you speak of? Pictures? I'd be interested in something like that.
Also, does it have the ability to wirelessly transmit info to anythign besides the printer? Like a wlan network?
sorry for all the questions... :)
In response to orangezero, "Is is level?" that's the beauty of it. If the patients head is cocked, you **** the instrument to match. Look at the angle of his eyes, and tilt the R'max to match. Especially with pts who don't speak English. Most of my pts are Latin and I do no conversing with most of them. 4 foot pts or 6 foot pts, the R'max can be adjusted to their height in one 1 or 2 seconds. With a bunch of kids, I sit in a chair while they stand.
From settlement of the pt in front of me until I align the pupil, and the machine reads the Rx is about 10 seconds. With infrared info to the printer, disposing of one pt and aligning the next in front of me consumes a grand total of 1 minute. I can comfortable refract 60 per hour.
For those patients who cannot stand up in front of me, wheelchair bound etc. it is still excellent and quick. The only criteria is that you have to be in relatively dim light. I worked in the open shade in a forest once and readings were quite erroneous.
I make the battery pack from five 5 AHr NiMH "C" cells, welded connections, and encased in shrink tubing with a short pigtail and plug. It weighs one # and fits nicely in you pants pocket. I make an oak insert that fits in the R'max handle in place of the DR-10 camcorder battery. It has about a 2 foot pigtail which mates with the battery plug. I sell this pack to non-profit missionary people at $41 - which includes a recent big cell price increase. One pack lasts about 4 hours for maybe 200 pts. I searched for several years for a suitable charger. I tested many and found some that claimed to be "smart" but would not terminate the charge before overheating the battery. Just reently, I have found a charger which charges properly and will work at inputs from 100 to 220 VAC, automatically. It will charge the battery in about 5 hours.
I have not done any experimenting with wireless transmitting. It can communicate with a laptop., which can in turn transmit elsewhere.
I have made up about 15 of these battery/charger systems for VOSH teams. It also displaces the Retinomax charging stand which is big and expensive. I have also made an adapter block for the printer so you can run all day on one of these NiMH battery packs. The system allows me to work in remote villages which do not have AC power. I charge up overnight at the hotel.
My biggest day was in Peru, working for 12.5 hours and refracting 750 pts. You cannot do half that many with a tabletop. I have no experience with the R'max in US optometry business. Beto
Orangezero inquired on refraction time of R'max. With experience, it takes a second or so to align the machine up with the pupil. On alignment, it immediately within a few parts of a second starts taking successive refractions. It's computer compares the successive readings and when satisfied with a lot that match, stops refracting and displays OK. For 90% or so of the patients with spheres below about 10 and cyls below 5, this process takes maybe 2 or 3 seconds. Shifting to the left eye and reading takes another 2 or 3 seconds. For very small pupils or quite high cyls and spheres, and slight unsteadyness of the operator or patient, It may take up to 20 seconds to get readings. It takes another 5 or 10 seconds to push "print" and, by infrared, transfer data to the printer. The printer is slow and takes maybe 10 seconds to churn out the data. Immediately on pushing print, the data can be read in the eyepiece. For improved steadiness, I back the pts up to the wall.
I have gone to Mexico several times with the Lions Club and also we have done vision project with the migrant workers in the eastern end of Coachella Valley (where your lettuces and honeydews come from!).
We have used the Desktop AutoRefractor from Canon and it seems to work pretty good and it is much faster than doing refraction by itself (we saw 250 people that day). The Lions Club has dispensed away doing refraction using phoropters.
I myself prefer phoropters.
I did a church project in Tijuana without the Lions Club and I had to do refraction without phoropters or autorefractors. So I had to use trial frames and lenses. I had to use my smarts in trying to predict the patient's prescription. I had to consider the uncorrected VA, the age, the chief complaints to formulate a possible prescription and check it using the trial frame. It is true that it was very draining at the end of the day as I had to constantly think...but that is a method that is available for cheap...and actually it is quite rewarding for me and it was a good mental exercise. Of course I do speak Spanish fluently and that helps greatly in communication. If a patient came in and had uncorrected vision that was 20/80, and is able to read upclose with no problems, then I pick the minus trial lenses and go from there. If he or she is not able to read upclose either and it 55 yrs old, then I pick the plus lenses and go from there. If I am not able to correct well then I pick the cylinder lenses and turn it around till patient says it is clearest at this spot.
Hope my method helps!
If you have further questions, feel free to ask me !
thanks for the comments psaturn.
when I went down on some svosh trips, the majority of our glasses were given out based on retinoscopy.
A question for the group: Do you all use the autorefractor as "just one test", or do you prescribe straight from it? Does anyone actually edge lenses there, or are they donated frames?
My personal view of autorefractors is that there are many, many autorefractors that over-minus, some less and some more. I constantly read online how one autorefractor or another is "always dead on" or whatever, but I've yet to find one... Certainly, they have their place.
PSATURN AND Orangezero have commented on refraction in missions. From my experience for 23 years on VOSH trips with various teams, until the Retinomax came along in 1995, nearly all of the VOSH team ODs used retinoscopy. Very few used trial lenses, and I saw one phoropter on one trip. Most still use retinoscopy, along with VA as a verification and massaging of the Retinomax reading. the Retinomxa vastly speeds up refraction. A few OD prescribe off of the R'max readings.
Nearly all VOSH teams use recycled glasses from the Lions. My teams use them and also use new readers available for 50¢. We don't get enough of them from the recyclers.
TheODs on my teams praise the R'max output, though they report it consistently overminuses spheres by 0.5 D. Cyls and axes are very close. A web search for studies on its accuracy verifies these numbers.
I have completed 50 four day missions as Retinomax operator and other than running out of battery on my first trip, it has been a great and reliable instrument. Check out my VOSH KY (beto) trips on VOSH.org I did solve the battery problem by devising a separate 1# power pack feeding the R'max through a wire cord.
I checked the link for the initial poster and I see why an autorefractor would be helpful.
The Guatemalans native may speak a little Spanish and no English at all. They speak different native dialects.
Right now I cannot think of any auto refractors for donation yet, my Lions club does not even have one....but our district does.
I have done refractions via phoropters on deaf / mute folks, autistic children, French ladies, crazy Italian women, Portuguese shepherders and Mexicans that do not even know how to read....so, where there is a will there is a way !
And yes, retinoscope is the cheapest way to get the results...remember, autorefractor is a form of retinoscope !!!
We have used a hand held and desk autorefractor for many years. When we go to out of the way places the hand held works the best but it not very accurate. We use the autorefractor reading as the intial measurement and proceed to give them a final check with a phoropter. When you see a lot of people our staff really appreciate automation.
Our staff are all trained in Guatemala. The courses here provide no training using a retinoscope.
We have made all our new glasses in Guatemala. There are labs here that do a very good job and not too bad on price.
Dear 35 yr old guy,
I do concur that autorefractor is a tremendous asset in doing refraction. I have been in this office that is right in downtown of a major resort town and I did not have any autorefractor for 6 yrs. When I had children patient and they gave odd responses during refraction, I would dilate them and do cyclopegic retinoscopy or send to our other offices (I am an employee of a major medical eye clinic) that has an autorefractor just to check. One office had upgraded their equipment so then the other offices received the hand-me-down and I finally got a Nidek autorefractor ! Sometimes it misbehaves...but it is far better than nothing !!! This is to show you that there are professional offices in the US that do not have autorefractors !!!
I just wanted to commend you on your work in the remote part of Guatemala!
Not many folks would be willing to do that and you did it !!!
I may do it when G-d calls me to it !!!
Then I will be screaming on this board for a FREE AUTOREFRACTORS !!!
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