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On Laser Surgery for Near-Sightedness

On Laser Surgery for Near-Sightedness

Sunday, August 27, 2005

About 10 years ago I was rear-ended by a station wagon on the highway and as I lay on the table in the radiology suite that day, terrified my spine was broken, the X-ray tech said to me in the most comforting way possible, "So, you're an eye doc? What do you think about that new laser surgery to replace glasses?"

Sigh. My neck turned out to be fine, but this is the most common question I get asked next to, "You're a doctor? I have this rash, wanna take a look?" 

So, it was no surprise when I got the following message from my friend VertigoX: 

I have been wondering for a while if I should get laser surgery to correct my eyes… About Grade 11 I started to wear glasses and the prescriptions for my glasses are getting stronger and stronger... I've heard rumours that the stronger the prescription along with the amount time you wear glasses, your eyes will get steadily worse. What are your thoughts on it?

Here's my response to him (keeping in mind I trained as a Retina specialist, not a Cornea specialist):


Dear VertigoX:

Well, you’re 26, so if you are going to get laser surgery, this would be a good time. That being said, a few caveats:

1. Although laser is used to change the contour of the cornea, it is in fact surgery. A flap of cornea is cut and lifted to expose the area that is lasered. Since the eye is being cut into, there is the possibility of complication, most notably scarring, which can cause permanent haze or blur. Also, you could get an infection. The possibility is small, but not insignificant.

2. Although laser surgery is about 90% effective in terms of getting you to 20/20 or better, there are still people that need glasses afterwards, just to tweak the vision to perfect. Almost everyone gets vision good enough that they don't need glasses to drive etc, but many people still need glasses to get the vision they expect.

3. I am guessing that you are near-sighted. However, since you only needed glasses after age 16, I would also guess that your near-sightedness is not terribly severe. (When I say severe, I am talking a prescription of -12 Diopters or so). If you are like me, when you take off your glasses you can see crystal-clear about 6 inches in front of your face. My prescription is about -6.00 Diopters.

4. Everyone, and I mean everyone, needs glasses for reading after about age 45. Also, many folks get cataracts after about age 65. So, no matter what, you will need glasses when you are older. But, if you get laser surgery now that would give you a good 20 years with little need for correction which is a pretty good deal.

Big breath. Okay, so let's talk about near-sightedness and changes of vision with aging.

Near-sightedness is a plague of modern civilization. We get it because we all do such huge amounts of near work, causing our eyes to strain with what is called "accomodation". When we look at things up close, several things happen, but most notably the muscles pulling on on our lens tense up to help us focus - this is called "accomodating". If we are strongly accomodating for long periods of time (by, reading, or playing on the GameBoy) the tensed muscled around the lens put out chemical signals which call for help.

The way the eye responds to the call for help from the lens muscles is to release growth factors that encourage the eye to lengthen. With a longer eye, the lens doesn't have to distort as strongly to focus images on the retina.

Obviously, your eye lengthens as you get older as well (up until your early 20s) so you need increasingly strong glasses even when you are NOT using your lens to focus (anything beyond 6 meters or so). Most normal kids are born a little far-sighted and use their accomodation to see up close until they get old enough for the eye to reach the mature length.

Anyway, the fact that your prescription is getting stronger and stronger is probably not so much a symptom of your glasses prescription, but rather the fact that you have the same bad eye habits as every other educated person in the world. I went up an entire Diopter in my prescription during my second year of medical school, as did many of my colleagues. Law students also have the same problem. Interestingly, as some third-world countries increase their literacy, the incidence of near-sightedness shoots up to about 30%, which is what it is in the US, Canada and Europe.

What can you do to slow the change in your prescription? When you are reading, or playing Game Boy, or doing any near work, just take a break every 30 minutes or so and focus on something at least 20 feet (6 meters) away. I tell my son to look out the window at the horizon if possible. Give it a good 30 seconds. What this does is relax your accomodation. Although your prescription may still progress, you should be able to slow it a bit using this trick. 

Whew! Okay, so now let's talk about the surgery. If you decide to have the procedure done, be sure to get someone who has done a TON of the procedures. You can look on the web for someone. The guys that advertise the most aren’t going to necessarily be the best ones. You need to find out how long they've been at it. To be honest, the computers that calculate the correction and perform the procedure are so self-sufficient nowadays that pushing the little button isn’t that difficult.

HOWEVER, the reason you need someone who has done it a long time is that you want someone who has been at it long enough that they have had experience with the 1/300 patients who have complications (haze, scarring, infection). Those people will be the best qualified to tell you if you are not a good candidate, or if, God forbid, you have a complication, to treat you to minimize the long-term impact of infection etc.

I don’t know what the situation is in Canada, RE whether they allow optometrists to own and operate free-standing laser clinics or not. Here in the US optometrists can do laser in Oklahoma. However, because this is surgery, I would recommend seeing an Ophthalmologist (M.D.) for the procedure because if there is a complication, an M.D. will be handling you themselves and not turfing you to another provider the way an optometrist would. I always figure it is better to go to the person who will be ultimately responsible for you if you have a problem. More incentive to get it right the first time, correct? Laser-surgery patients tend to be EXTREMELY demanding and very unhappy if they don’t get perfect vision afterwards (another reason why I am happy not to be a cornea specialist) and tend to see M.D.s exclusively. That is what you want: a surgeon who does not want to have an unhappy laser patient on his hands. ;-)

So, my opinion: Well, I wear glasses. But I am 42 and am already having trouble seeing at near. So, regardless, I’m going to have to wear glasses, and I have to have >20/20 vision if I want to do microsurgery. If you were a pilot, or a diamond cutter, I would say it isn’t worth the risk. But, I think you said you aren’t either of those things, and you are 26. It sounds like you would be a good candidate.

So go see an M.D., and have them do an evaluation. If your prescription is terrifically high (>12.00 Diopters) there is a chance you won’t be eligible. But it doesn’t hurt to try. Also, I’ve heard this new “wave-front” technology is actually getting people to ultra-high vision, like 20/10 or something. That would be awesome if it works!

Your pal, 

Linnea AKA Elnea

August 25, 2005