Royal Gramma
Registered User
How impressed are you all that have had PRK with your vision quality post PRK (after several months of stabilzation and improvement)? How noticeable and annoying are the visual aberrations that come with PRK?
I just want to get some qualititive observations from those that have had PRK. Maybe they will get me off the fence regarding PRK. I still would consider pretty hard to convince. Here's why:
Despite what many claim they experience, you cannot have better vision post PRK than you would have pre-PRK with correction. All types of refractive surgery induce higher order aberrations. Even customized wavefront ablations. The aberrations that wavefront guided ablations induce are just not as severe.
From the Bausch and Lomb website regarding their Zypotix vision correction systems which couples their Zywave aberrometer and their orbscan topographer with their Technolas 217z laser:
The aberrations induced by wavefront PRK are simply not as bad as those induced by traditional PRK. What does this mean?: All refractive surgeries induce aberrations, which can lead to decreased contrast sensitivity (among other things such as haloes, double vision, starbursts), and it is impossible, at least with todays technology, to have better vision with PRK than what you would be able to get with contacts. This is especially true with RGPs, which can decrease higher order aberrations by around 70% (much better than you would get with PRK, which at best is no net gain in aberrations).
You definetely get a reduction in the quality of your vision with PRK. However I can see why the military has been such an enthusiastic adopter of PRK once it was proven as medically safe: It's good enough vision to get the job done (pilots included) and a much preferred alternative to glasses and contacts which can problematic in a combat zone. It's the issue between quantity (Snellen acuity) and quality (how good is you vision, even if it is 20/20).
All these folks who tout how great their vision was after PRK, I think don't remember how good their vision was corrected before PRK, especially with contacts. Especially with bilateral PRK, which is most common right now, you have no reference point to judge you post PRK vision with. With me, for example, if I go without glasses or contacts for a few days, I will oftentimes say to myself, "Hey, my vision isn't so bad...". However the minute I put my contacts in, it's "WOW! What a difference!"
I am hoping that the Coast Guard will adopt the Navy's new SNA contact lens policy. Granted, it usually takes the Coast Guard a few years before they will adopt Navy policy, so I probably shouldn't be too optomistic that the Coast Guard will have this policy in the books in time for my second tour about 3-3 1/2 years from now.
To all those who have had PRK, how happy are you with your vision?
I just want to get some qualititive observations from those that have had PRK. Maybe they will get me off the fence regarding PRK. I still would consider pretty hard to convince. Here's why:
Despite what many claim they experience, you cannot have better vision post PRK than you would have pre-PRK with correction. All types of refractive surgery induce higher order aberrations. Even customized wavefront ablations. The aberrations that wavefront guided ablations induce are just not as severe.
From the Bausch and Lomb website regarding their Zypotix vision correction systems which couples their Zywave aberrometer and their orbscan topographer with their Technolas 217z laser:
Although the ZyWave® Wavefront System measures the refractive error and wavefront aberrations of the human eyes, including myopia, hyperopia, astigmatism, coma, spherical aberration, trefoil, and other higher order aberrations through fifth order, in the clinical study for this PMA, the average higher order aberration did not decrease after Zyoptix Personalized Vision Correction.
The aberrations induced by wavefront PRK are simply not as bad as those induced by traditional PRK. What does this mean?: All refractive surgeries induce aberrations, which can lead to decreased contrast sensitivity (among other things such as haloes, double vision, starbursts), and it is impossible, at least with todays technology, to have better vision with PRK than what you would be able to get with contacts. This is especially true with RGPs, which can decrease higher order aberrations by around 70% (much better than you would get with PRK, which at best is no net gain in aberrations).
You definetely get a reduction in the quality of your vision with PRK. However I can see why the military has been such an enthusiastic adopter of PRK once it was proven as medically safe: It's good enough vision to get the job done (pilots included) and a much preferred alternative to glasses and contacts which can problematic in a combat zone. It's the issue between quantity (Snellen acuity) and quality (how good is you vision, even if it is 20/20).
All these folks who tout how great their vision was after PRK, I think don't remember how good their vision was corrected before PRK, especially with contacts. Especially with bilateral PRK, which is most common right now, you have no reference point to judge you post PRK vision with. With me, for example, if I go without glasses or contacts for a few days, I will oftentimes say to myself, "Hey, my vision isn't so bad...". However the minute I put my contacts in, it's "WOW! What a difference!"
I am hoping that the Coast Guard will adopt the Navy's new SNA contact lens policy. Granted, it usually takes the Coast Guard a few years before they will adopt Navy policy, so I probably shouldn't be too optomistic that the Coast Guard will have this policy in the books in time for my second tour about 3-3 1/2 years from now.
To all those who have had PRK, how happy are you with your vision?