What is the Range of Lasik for Vision Correction?

The most you can usually safely treat with LASIK without cutting too deep and going too deep into the cornea, and violating too much tissue, and causing iatrogenic keratoconus, is about -9  or -10. Maybe -11 if you start out with thick corneas, and don't do CustomVue as that takes away more tissue when you laser compared to the older standard non-custom procedure.

With LASEK, which is a much more advanced version of the older PRK that was the initial laser procedure that was invented by Drs. Steven Trokel and Francis L'Esperance when I was a medical student at Columbia, you can safely treat up to -19 or even -20, maybe -21 or -22 if you start with a thick cornea and don't choose Custom (which you can't do that high anyway, the company doesn't let you as it's not FDA approved for that high). I did this on a patient in 2010 who flew all the way to NYC to have me treat her, as everybody in China is still doing LASIKs, and could not treat her -22 (or do a LASIK and leave her -10, which would be pretty useless). We got her entire Rx successfully AND SAFELY treated, and made her 20/25, which is a FANTASTIC RESULT for someone starting -22 and without 20/20 potential to begin with!;)

So put it this way: ANYONE who is ANYWHERE NEAR the LIMIT for LASIK should NOT get it, and should get LASEK instead, because it's WAY SAFER. And don't go to someone who says they'll do a PRK on you for that Rx, as I did my last PRK in 1999, and it's an ARCHAIC procedure that will hurt for WEEKS and may very well cause enough inflammation to cause PERMANENT SCARRING.

You also need to go to a surgeon who is so experienced using Mitomycin C (MMC) that he or she is comfortable and confident, as without this, you WILL SCAR if you have such a high Rx, but with it you WON'T (they should use this every week as we do, or they may mix it wrong, and it's so potent it's used for cancer chemotherapy, and if you mix it with a too-high concentration, you will cause a CORNEAL MELT which means the LIQUID CONTENTS OF YOUR EYE WILL LEAK OUT THROUGH A HOLE IN YOUR EYE. but we've used this about 1,000 times WITH NOT A SINGLE COMPLICATION as I have 2 senior fellows (MDs) who are the ONLY ONES ALLOWED TO MIX THIS, not a "tech" or "OD" or anyone who is not a FULL MD.

Advanced laser vision correction is able to treat up to +6.00 diopters of hyperopia or farsightedness. It can also treat astigmatism up to six diopters and nearsightedness up to -12.00 diopters, depending on the laser chosen for the treatment. Of course it is necessary to otherwise be a good candidate for these procedures, and not everyone is capable of having this programmed into the laser for their particular eyes.
Assuming that the shape of the eyes is symmetric and normal on scans and testing, there are no history problems or extreme dry eye type problems, it is now possible to treat fairly high levels of correction by LASIK. Some patients treated above +4.00 will experience a degree of regression, and repeat procedures may be possible in some of these cases.
Nearsighted patients have about double the range where treatments as high as twelve diopters can be done if there is enough corneal thickness preoperatively.
There are other considerations, especially in these higher prescriptions, so it is important to get an opinion from your local LASIK expert. For instance, if the cornea is already very steep, it may not be able to be steepened the additional amount necessary for the higher end of the correction range. The values given here are the FDA range for a particular laser where the treatement has been shown to be safe and effective, other lasers may not have the same range available.

The absolute range for correction of nearsightedness, astigmatism and farsightedness goes from about -14.00 to +6.00, so, technically, at +5.50, this patient may be a candidate. The more important question is what is the thickness of the cornea and the "shape" of the cornea, before we perform LASIK. Obviously, this question can only be answered after a thorough eye examination and consultation. At my office in Maryland, we do not charge for this visit.

When considering Laser Vision Correction it is vitally important to choose an experienced surgeon who has a well trained staff that can gather all of the necessary ocular data and help you decide if treatment is the right thing for you. To be honest, over the years I have performed LASIK on several hundred highly farsighted patients like you......I have also told several hundred more that they did not have the proper corneal shape to be treated.

Hyperopic (or farsighted) LASIK surgery can be done for corrections up to +6 diopters with most advanced lasers. It IS FDA approved for these high corrections. However, most experienced surgeons have seen best results up to +4D or so, with results between +4 and +6D being good but not as good.
For higher corrections, there is a higher risk of night glare/halos, increased risk of subtle loss of best corrected visual acuity, and a higher risk of needing a touchup surgery. Also, for people over 40, high plus corrections do not typically allow us to do monovision, since we might have to program the laser for even more that 6D to create some nearsightedness in the reading eye.
If over 40, and +5.50D, you may have LASIK. But, you may be better suited for a procedure like Refractive Lens Exchange (RLE).