Refractive Error vs. Visual Acuity

[AMN1]

while looking over i saw that you must meet the standards for both Refractive Error x.xx and Visual Acuity 20/xx. My plan is to become an officer and a pilot in the Air Force, but for now I am enlisting because i need the direction and motivation. Right now my contact prescription says 3.5 which would put me within limits of the pre-prk refraction error of 5.5.My question is what is the difference between the two test, and why are both needed? Also, Since i will work Mx on the flightline does this give me a better chance at receiving the surgery?

Edited February 18, 2011 by Storm

[Bayou_Eagle_Driver]

From what I understand, the only part that visual acuity plays is that you need to be correctable to read the 20/20 line of the vision test chart to pass a FC1. The refractive error is more important when it comes to being within the limits, and getting waivers etc.

Additionally, your dry refraction does NOT MATTER. The ONLY refraction that matters anything to the Air Force is the CYCLOPLEGIC REFRACTION (Eyes Dilated).

The Air Force will only pay for refractive surgery if your career field requires it, which MX does not.

[Guest goducks]

while looking over i saw that you must meet the standards for both Refractive Error x.xx and Visual Acuity 20/xx. My plan is to become an officer and a pilot in the Air Force, but for now I am enlisting because i need the direction and motivation. Right now my contact prescription says 3.5 which would put me within limits of the pre-prk refraction error of 5.5.My question is what is the difference between the two test, and why are both needed? Also, Since i will work Mx on the flightline does this give me a better chance at receiving the surgery?

It's really the refractive error that matters and the cycloplegic refraction (as ȘÅİňŦ referenced) is the one that is used. Uncorrected visual acuity is measured, but it's rarely a show-stopper. You are well within the pre-op limit for refractive surgery (now -8.00). Once you are active duty, the AF will offer you refractive surgery through their own surgery centers as part of the Warfighter (non-aviation) program. That's assuming you are a good candidate, have your commander's approval, etc. Working the flightline does not give you priority, however, the USAF surgery centers have plenty of availability so that's not an issue.

[AMN1]

ok, thanks for the information saint and goducks. its nice to know that my eyes will not stop me reaching my goals

[Skitzo]

I'm getting older and therefore my powers of accomodation are getting worse. I anticipate getting kicked off of the SCLP just because I can't get a lens with enough astigmatism correction that is on the approved list. I have an approved waiver for astigmatism based on my initial FC1 medical and get it updated every year. I was wondering since my prescription changes every year (presumably because of less power to accomodate) why the docs don't just go with a cyclopegic refraction to prescribe my eyeglasses? I mentioned it to my doc this time and she preferred to just do a manifest refraction. Any reason why a cyclo refraction wouldn't be warranted? Wouldn't this result in a pair of glasses that would correct my true eyes without regard to accomodation?

[Guest goducks]

I'm getting older and therefore my powers of accomodation are getting worse. I anticipate getting kicked off of the SCLP just because I can't get a lens with enough astigmatism correction that is on the approved list. I have an approved waiver for astigmatism based on my initial FC1 medical and get it updated every year. I was wondering since my prescription changes every year (presumably because of less power to accomodate) why the docs don't just go with a cyclopegic refraction to prescribe my eyeglasses? I mentioned it to my doc this time and she preferred to just do a manifest refraction. Any reason why a cyclo refraction wouldn't be warranted? Wouldn't this result in a pair of glasses that would correct my true eyes without regard to accomodation?

I'm not sure I totally follow, but I'll try to explain. Let me know if it doesn't cover your questions fully.

We can't often prescribe the cycloplegic refraction because you won't tolerate it. Although it does reflect the true refractive error, it doesn't represent the natural state of your eyes given the effects of accommodation. You would likely think your cycloplegic refraction looks quite blurry if you tried wearing it.

However, accommodation and astigmatism are totally different things that shouldn't affect each other. Therefore, I don't fully understand your question about astigmatism (and getting kicked off the SCLP) as it relates to accommodation. Changes to your accommodation should not affect your need for astigmatism. Perhaps I'm completely misinterpreting.

As far as the contacts and astigmatism are concerned, there are limits to what is allowed within the program. You can have up to 2.00 Diopters and stay on the contact lens program. If you need more astigmatism and you want to keep wearing contacts, you would need a waiver to do so. That doesn't mean you can't wear them, it just means you don't fit within the parameters of the program. Contact lenses can have any amount of astigmatism, although realistically they quit working above about 4.00 Diopters due to blur associated with rotation of the lens.

Hope that helps a little. Let me know if not.

[Skitzo]

Totally helps, thanks for educating me. Didn't realize that a cyclo refraction would be so blurry as a presecription. I already have a waiver for the SCLP for astigmatism over the limit. I'm hoping the next set they have ordered me works because as it was explained to me there are limits to what's approved vs what's out there. I'm having a difficult time with fit.

OD: +.75 -1.75 042

OS: +.05 -3.25 178

My astigatism OS under cyclo was -3.5

Already tried Frequency 55 Torics and were on them for a couple of years, this year I couldn't see well enough with them. Not sure what lens are up next.

[Guest goducks]

Totally helps, thanks for educating me. Didn't realize that a cyclo refraction would be so blurry as a presecription. I already have a waiver for the SCLP for astigmatism over the limit. I'm hoping the next set they have ordered me works because as it was explained to me there are limits to what's approved vs what's out there. I'm having a difficult time with fit.

OD: +.75 -1.75 042

OS: +.05 -3.25 178

My astigatism OS under cyclo was -3.5

Already tried Frequency 55 Torics and were on them for a couple of years, this year I couldn't see well enough with them. Not sure what lens are up next.

I think the problem you are experiencing is that the amount of astigmatism you have in the left eye is pushing the limits of what soft lenses will successfully correct. Astigmatism is a refractive error that is directionally based. You need a certain prescription in one direction and a different prescription perpendicular to the first. If the lens turns when you blink or doesn't orient properly in the first place, the powers of the lens won't match what your eye needs. We can sometimes change the power of the lens to make up for the fit, but we can't make a lens work if it is rotating (as this changes with every blink). The amount of blur created by lens rotation is a product of the rotation and the amount of astigmatic correction. With low astigmatic correction a fair amount of rotation is OK; with high amounts of astigmatism, a little rotation results in a lot of blur.

Different contact lenses fit some eyes better than others. Sometimes it's just a matter of finding the right lens. The other alternative is to use a rigid lens, which works on a totally different principle. I would also suggest refractive surgery, however, if you fly for the AF, you don't qualify for surgery if your eyes have more than 3.00 D of astigmatism. Of course, I haven't mentioned spectacles. They don't rotate, so the astigmatic correction is stable. They also don't work well with much of the helmet mounted systems that aircrew use.

GD

Regarding what is "approved".....we will use any lens we can to keep you flying. The "approved" contact lens list is designed to try and keep aircrew in a manageable number of lenses that can be supported by every optometry clinic. However, if nothing on the approved list is working for you, we will work to find a contact lens that does. The list is not intended to limit what you can use, but rather to try and select from that list first and then move on if a successful fit can't be achieved.

Edited March 6, 2011 by goducks
More information

[Skitzo]

Thanks for all of the great info GD. I didn't know nor did my doc say that we could try lenses not on the "approved" list. Would non approved lenses require another waiver?

I am fine with glasses for flying, frankly even when I was wearing contacts regularly I found that they dried out on longer duration flights.

[Guest goducks]

Thanks for all of the great info GD. I didn't know nor did my doc say that we could try lenses not on the "approved" list. Would non approved lenses require another waiver?

I am fine with glasses for flying, frankly even when I was wearing contacts regularly I found that they dried out on longer duration flights.

A non-approved lens might require an additional waiver. It also may require that you process through the ACS. Most important is to find something that works.

[sooners9692]

I've had a similar issue come up in the past week. I was just informed I was permenantly DQ'd because of my vision. Wanted to get some thoughts on this as I'm not too familiar with how these eye tests go. I passed the MEPs physical, but won't be sent to FC1 because I will more likely than not be DQ'd there. My uncorrected vision is 20/400 in both eyes. My uncorrected distant vision is 20/50 ® and 20/30 (l). The normal limits without a waiver are 20/200 for distant vision and 20/30 for near. So this puts me over in both distant and near vision, but I assumed this would be at least waiverable? I also took a look at the "Medical Waiver Guide" posted online and per the Guide, in order to be eligible for a
waiver for vision my Refractive error must be within + or - 3.00. My eyes are at -3.75 and -4.00, outside the limits that are in the guide from what I have seen. Is there any possible way around this to at least get my FC1? Waiverable even though the guide says I'm out of limits for it? I know PRK is in the realm of possiblities but that would already put me a year out waiting, and I don't know if that is something I want to risk right now since I currently hold an FAA First class with no issues. I know my vision is bad but I neve thought a prescription level of -3.75/-4.00 would be a disqualyfing factor. Any help would be greatly appreciated.

[Guest]

The Snellen values for uncorrected vision (20/###) doesn't determine waiver

eligibility--just whether you need a waiver. You only need to be able to

correct to 20/20. The Refractive Error/Rx determines waiver potential.

The Excessive Refractive Error guide, which you cited, is the correct

standard for your condition. With your values, you are unwaiverable.

Unfortunately, the Air Force cares not for the FAA standards. There are

only 2 ways around these fact if you want to become an AF Pilot:

1. Get PRK, LASIK/LASEK, or epi-LASIK and wait a year to apply again with a

waiver. This is a time tested, proven Plan B for many applicants. Discuss

this with the MEPS docs BEFORE you actually get the procedure.

2. Try for an Exception to Policy (ETP). This a hail-mary, Plan J for the

desperate and deluded.

[81L BLR]

Deaddebate is correct. The only other option would be to press forward for a FCII to fly RPA.

[Bob]

I was just informed I was permenantly DQ'd because of my vision. My uncorrected vision is 20/400 in both eyes. I know my vision is bad but I neve thought a prescription level of -3.75/-4.00 would be a disqualyfing factor.

I am having a hard time understanding why this is surprising news. 20/400? Seriously?