rizuhbull posted:

So Lasik has no effect?

rizuhbull posted:

So Lasik has no effect?

Metal Geir Skogul posted:

Gather round, children, for a very quick and dirty explanation of Eyes, Glasses, and You.

-------------BASICS-------------

Your eye has a lens in it. This lens resides underneath your cornea. This lens focuses light onto your retina. When you have "perfect" vision ("20/20, though that's a bullshit measurement and I'll tell you why), the lens in your eye does what's called accommodation, or shape, to focus this light. When you're looking at something in the distance, the lens needs to get pulled flat a bit. To see up close, it needs to squish down and become thicker (I could have this backwards, I'm a bit tipped right now) Flying saucer versus, well, a taller, fatter flying saucer.

If you have imperfect vision, that means that the lens in your eye can't accommodate enough to focus the light. For some, the back of the eye is too close to the lens, and when looking at things up close, the lens can't squish enough to make the light meet it; but, when you're looking at things further away, that's still within the range of accommodation of your lens. These people are hyperopic* or "far sighted." They can see fine far away, but not up close. For other people, the retina of the eye is too far away for the lens to flatten out enough to focus. These people are said to be mopic*, or "near sighted." They can see up close just fine, but not far away.

Now, whether you have perfect vision, or are my/hyperopic, something will happen starting around age 40. The lens in your eye will start to harden, and lose its accommodation powers. This is called "presbyopia." In general, the "resting point" of the lens is focused out to infinity, and that's why you feel yourself have to "manually" focus on things up close after spacing out at your desk at work, because your eyes were resting and that means you were focused out into the distance.

This hardening/presbyopia will manifest, in somebody with good vision, as losing the ability to read up close. Even people with perfect vision will start struggling around their early thirties at doing close-up manual work. (I'm thirty and even I benefit from wearing some cheap +.75D reading glasses when doing soldering and the like, because it reduces the strain on my eyes with my contact lenses in.) Eventually, and usually around 44-45, people buy their first pair of dedicated reading glasses.

Now, for somebody with imperfect vision, presbyopia will start to add a "boundary" to their natural focus range. If you're farsighted, up until that point, you could wear glasses for reading, but didn't need glasses to drive during the day or at night. But, when presbyopia sets in, you may need night driving glasses, as being out at night opens up the pupil, and would naturally require the lens to focus somewhere due to the bigger aperture. Or, the presbyopia could "set" the lens at an intermediate (say, 10-20 foot) focal point, and you'd need glasses 100% of the time for anything involving distances greater than that. Likewise, if you're near-sighted, your natural focus range was closer. If you were mildly (-2.00 or under) myopic, you might have been able to see things from the tip of your nose out to your fingertips. Presbyopia will push that "close" boundary out from your nose further and further, until you only have one "sharp" focal point a set distance out. Eventually, the presbyopia will "surpass" the geometric ability of the eye, and even a nearsighted person would/will have to wear glasses 100% of the time, even for close work that a few years prior would have been no problem.

-------------LASIK-------------

LASIK is a procedure where they temporarily remove the cornea (the "flap" they talk about), and use a laser to correct the shape of the front of the lens. This will shift the "natural" focal range of the lens from something that was previously geometrically out-of-bounds with your retina, to something that's within range. That's all well and good.

However, LASIK will only really give you 100% benefit** if you do it at a point in your life when the lens in your eye is still flexible. Once your lens loses flexibility, the utility of LASIK is reduced. After presbyopia sets in, you'll have to choose which focal point you want for the surgery. Do you want perfect distance vision, and have to wear glasses to use a computer and to read (usually separate pairs, or a set of intermediate/reading glasses that are bifocals/trifocals/progressives)? Or are you a homebody that wants a focal point a few feet out for computer use and cooking, and instead needs glasses to drive or do other distance vision activities? Or, do you want the worst of both worlds, Monovision, where one eye is distance and one eye is up close and you lose all depth perception and it is also a poo poo procedure (I'm not biased)?

These are your choices, and kind of remove what people traditionally think of (and are advertised) as the main benefits of LASIK.


**LASIK can still benefit somebody like me with a -7.00, or somebody with a lot of astigmatism, by reducing, but not eliminating, the prescription they would otherwise require. This also reduces cost of specialty lenses, and can improve depth perception and clarity, even if you still have to wear contacts or glasses. Even after presbyopia sets in, somebody with a high prescription might choose LASIK for that reason alone.

*"myopia" and "hyperopia" are deceptively self-explanatory, but not in the way most people think. Hyperopia = Hyper (too much/far) + opia (optics), but it doesn't refer to what you can see. It refers to the fact that the focused light in your eye would be beyond, or behind, the retina. Myopia, same thing. Focused light falling short of the retina.

tl;dr Your eye has a "range" of distance it can see at. Farsighted people are generally X feet out to a 300 feet. Nearsighted people are from X feet in (but no further), to their nose. Good vision people are from their nose, out to 300 feet. LASIK can correct the near/farsighted people's "range" to be from their nose out to whatever. However, around age 40, this range will narrow for everybody, until it narrows down to a single point. LASIK can't give the range back, it can only move the point in or out.

Here's a quick picture I whipped up in an advanced photo editor:

LASIK after presbyopia can only shift around that focal zone, but it cannot expand it.


EDIT: I FORGOT ABOUT THE BULLSHIT 20/20 MEASUREMENT.

"20/20" or "20/40" or the like are just referencing your distance vision at 20 feet, that's all. "20/20" means that, at 20 feet, you see what a theoretical person with perfect focusing would see. "20/40" means, at 20 feet, you're seeing poo poo like you were 40 feet away, or less clearly. The scale only goes up to 20/400, so if somebody goes "I see 20/20000" they're talking out of their rear end, or have a lovely optometrist that gave them a probably-bullshit (could be mathematically calculated but literally nobody bothers) number. It's a useless measurement as well, because it doesn't actually account for your true distance or near vision. A moderately farsighted person, or a presbyopic person, might test out to 20/20 or even 20/15, but be poo poo at reading up close, or actually seeing out past 20 feet and couldn't be trusted to drive. It's a stupid measurement and everybody hates it.

angryrobots posted:

Chillyrabbit posted:

Jumping into Lasik with my eyes closed (pun intended).

I'm setup for a PRK advanced custom wave front surgery in Calgary, AB 2 weeks from now. Since it looks like for the first 3 days are "do nothing with your eyes", what are things I can do to keep busy besides podcasts/audio books?

Chillyrabbit posted:

Jumping into Lasik with my eyes closed (pun intended).

I'm setup for a PRK advanced custom wave front surgery in Calgary, AB 2 weeks from now. Since it looks like for the first 3 days are "do nothing with your eyes", what are things I can do to keep busy besides podcasts/audio books?

snowparty posted:

If prk is anything like lasik you should be fine. Your vision will be mostly restored by then. The biggest thing is making sure you don't rub your eyes (as tempting as it will be) and make sure nothing gets in your eyes. They should give you some kind of protective lenses to cover them but if not you could always wear safety glasses. Just don't do anything too straining for the eyes such as playing video games too long or staring into the sun.

Shooting Blanks posted:

PRK is not like LASIK in my experience, and I did both. LASIK was effectively healed overnight and I was 100% fine. PRK took about a month before my vision was corrected, and I had no discomfort in that eye.

Edit: Don't get me wrong, the end result is fantastic for PRK and it is completely worth it. But don't sell it as if it's the same thing as LASIK, it's a different procedure and expectations should be set accordingly.

DelphiAegis posted:

I know this has probably been asked, but how much could I expect to pay for these procedures? Lasik/PRK.

I saw someone who was quite smart, they had an FSA with a grace period, and scheduled their procedure in said grace period, allowing both plans to pay for the whole thing, tax free.

Doom Rooster posted:

A bottle of Advil
More comfortable tinted goggles to sleep in
A big box of preservative-free artificial tears
Two books from Audible to listen to
A girlfriend planning to make dinner that night

For those that have already gone through it, anything else that I should have prepped to make my life for that first day a little easier?

Doom Rooster posted:

Tried to take [my glasses] off before hopping in the shower.

Shooting Blanks posted:

How much post op treatment are they recommending?

Edit: Consultation, not treatment.

PittTheElder posted:

Took me like a month to kick that habit.

PittTheElder posted:

In a nutshell, by a patient and not a doctor:

• LASIK - a flap is cut in the top layer of the eye, exposing the stroma layer of the cornea. Then a separate laser tool is used to ablate away portions of the cornea to reshape the eye. The flap is then put back in place at the end. LASIK is the cheapest option, with faster recovery times and low discomfort, which makes it basically the default option.
  
• PRK - instead of cutting a flap to expose the stroma, the outer layer of the eye is removed (I'm not sure how this is actually done), then the same laser ablation process is used to reshape the eye. The lack of flap cutting allows for surgery to be performed on people with thinner corneas/worse prescriptions, and is more attractive to people who for occupational reasons might expect to take routine impacts to the face (boxers, football players etc) which could dislodge the flap used in LASIK. Longer recovery times, more discomfort, more expensive, but the outcomes are pretty similar.
  
• ICL - This is what it was called where I got it (Gimbel Eye Center, Calgary AB) - Implanted Corrective Lenses - seems to be called a few different things. For patients with really bad prescriptions or really thin corneas (me on both counts), there's not enough corneal thickness to do the eye reshaping. So instead an incision is made in the eye, and a physical corrective lens is implanted in the eye, basically just a permanent contact lens. Same as cataract surgery, but your natural lens stay in. It was expensive ($4400CAD/eye, the lenses are custom made for your eyes, ask me about the eye ultrasound I got), but really easy; surgery was 20 minutes per eye, my vision came back just as soon as the assorted eye drops they'd given me wore off. I was given permission to drive the following morning, and there was essentially no discomfort. I had laser iridotomies done about two weeks prior to the lens implantation - they use a laser to make holes to allow fluids to get where they need to once you have an extra lens in your eye - but it sounds like that may not be necessary now, lenses that allowed fluid flow were on the horizon.
  

Also, as long as we're talking about the local establishments, gently caress LASIK MD in Calgary. They told me I was a candidate for PRK, I waited around a couple months till surgery date, and then only after I came in that morning did they tell me my corneas were too thin and the surgeon thought it was too risky. Later I went to Gimbel Eye Center to get ICLs, and Dr. Gimbel told me I was never even close to being an acceptable candidate for PRK. So I don't blame LASIK MD for making the call, but that really suggests to me that the initial assessment they do is basically all a marketing exercise and that the surgeon doesn't actually look till day of, which I consider extremely unprofessional.

PittTheElder posted:

PRK - instead of cutting a flap to expose the stroma, the outer layer of the eye is removed (I'm not sure how this is actually done), then the same laser ablation process is used to reshape the eye.

ibntumart posted:

The surgeon scrubs off with a small electric brush after you get some anesthetic eyedrops. Disconcerting, but painless.

PittTheElder posted:

In a nutshell, by a patient and not a doctor:

• ICL - This is what it was called where I got it (Gimbel Eye Center, Calgary AB) - Implanted Corrective Lenses - seems to be called a few different things. For patients with really bad prescriptions or really thin corneas (me on both counts), there's not enough corneal thickness to do the eye reshaping. So instead an incision is made in the eye, and a physical corrective lens is implanted in the eye, basically just a permanent contact lens. Same as cataract surgery, but your natural lens stay in. It was expensive ($4400CAD/eye, the lenses are custom made for your eyes, ask me about the eye ultrasound I got), but really easy; surgery was 20 minutes per eye, my vision came back just as soon as the assorted eye drops they'd given me wore off. I was given permission to drive the following morning, and there was essentially no discomfort. I had laser iridotomies done about two weeks prior to the lens implantation - they use a laser to make holes to allow fluids to get where they need to once you have an extra lens in your eye - but it sounds like that may not be necessary now, lenses that allowed fluid flow were on the horizon.
  

angryrobots posted:

What OTC eye drops did y'alls Drs recommend for long term use? I had it written down somewhere and can't find it.

I don't really have dry eye, but I've discovered that it's really pretty cool to wet my eyes first thing in the morning.

angryrobots posted:

What OTC eye drops did y'alls Drs recommend for long term use? I had it written down somewhere and can't find it.

I don't really have dry eye, but I've discovered that it's really pretty cool to wet my eyes first thing in the morning.