While I was living in Paraguay a couple years ago we had some volunteers come down. There were about 20 of them, mostly optometry students, some optometrists and some opticians. They were there for about one week and basically worked everyday all day in kind of an assembly line. I believe some Paraguayan nursing students would check the visual acuity, then it was on to the autorefractor, pressures, etc. etc. They had a group of us out there to translate and they just took one patient after another. I'm sure they saw well over a thousand people as it was in a big gymnasium-type place and there was a huge line, nonstop. I'm not sure if it was VOSH, but from my understanding it was coordinated with the Lion's Club of that area. I can't really answer from any insider perspective, but that was my experience with the volunteers. Hope that helps.