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January 22, 2010

Under The Knife

Frickin' Laser Beams, Part 1

by Will Carroll

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with Chase Gharrity

Fitzgerald said the rich are not like the rest of us. If he'd been around to write about modern baseball players, he'd have learned that not only are they rich, they're not like the rest of us in other ways.

A couple years ago, I was in Arizona for spring training. A player I'd gotten to know a little bit was giving me a tour of the facility when we got to the video room. I asked him about the kind of things he looked for and mentioned that he'd roughed up a highly regarded pitcher just a few days before. "Oh, he was tipping his curve," he said nonchalantly.

He went on to show me how the pitcher's index finger was coming up on a curve. In slow motion, I could see it. At normal speed, even after having had it pointed out, I could barely make it out. I turned to him and said, "You can't see that in time to do anything, can you?" He gave me one of those looks; he could. The guy I know wouldn't be offended by my saying that he's no All-Star and that he's barely hung on in baseball some years. Still, he has eyes that are simply superhuman.

Baseball players have always known that their eyes are their meal ticket. Rogers Hornsby refused to watch movies, thinking the flickering images could damage his eyes. Players have used all kinds of eye trainers, from the low tech to the very high tech, over the course of the game. When radial keratotomy became a surgery that was available, correcting vision was something many players considered. There's no record that a major-league player had this surgery, one that relied entirely on the skill of a surgeon.

In the mid-1990s, advances in medical science brought the miracle of laser eye surgery and, shortly thereafter, the procedure now known as LASIK (Laser in-situ keratomilieusis) was developed and perfected. At a cost that was reachable by many people as a nearly cosmetic procedure, LASIK not only allowed average people to get the procedure, but it also allowed surgeons many more opportunities to perfect the craft. By the mid-2000s, a procedure known as "wavefront-guided LASIK" was the state of the art, and it remains so. In this procedure, the eye is "mapped," and then a precise, personalized surgical procedure is possible, leading not only to 20/20 vision but also, in many cases, the final result is better than that.

As better outcomes and techniques made it into the mainstream, baseball players followed closely. Instead of being on the cutting edge-sports medicine normally is-baseball was a bit behind the curve. Let's face it. The eyes are not only a player's meal ticket, but it's a little bit creepy to lie back on a table and count on a surgeon to use a laser properly. That's a lot of trust for eyes worth millions.

Players began to dip their toes into the LASIK waters in the late '90s, with players such as Wade Boggs and Fred McGriff among the first to try it. There does seem to be some connection here, as players from, or living in, the Tampa area are over-represented in the early LASIK roster. Attempts to reach Boggs, McGriff, and others were not returned, but it's known that the doctor, Antonio Prado, remains a sought-after consultant to many players and teams. Players at this stage tended to be high-level players attempting to hang on a couple more years. Perhaps they were more willing to take a bit of a chance in order to stay in the game a bit longer. It's very difficult to say what, if any, result was gained here, but more than anything, there was no adverse result. If Boggs or McGriff-perennial all-stars-were willing to have surgery, why wouldn't a younger guy who is trying to get a little better?

How much better? There's no list out there of all the players that have had it. In fact, the teams themselves might not be able to compile a complete list. LASIK surgery is an elective procedure in most cases, handled outside the team's purview. There have been cases where the team hasn't been consulted or even informed afterward. This makes testing the effect difficult at best. Actually, it's a lot like trying to find the steroid effect. It requires a lot of legwork and a bit more guesswork than what makes the statistical gurus here at BP very happy. But that's what we did.

To take a quick-and-dirty look at the potential effects of LASIK surgery, we took a look at one of the more famous players to go under the knife-er, excimer laser-for this procedure, Jhonny Peralta. This powerful Indians shortstop-turned-third baseman had always drawn positive reviews for his bat. However, Peralta posted a rough 2006 season in which he posted a .245 EqA (down from .301 EqA the previous season). He decided to have LASIK surgery performed due to his inability to see Victor Martinez's signs from his defensive position, and also due to the hot streak he produced in a trial run with contacts during the final month of the 2006 season. Peralta is no better or worse a test subject here, but he's selected more or less at "random." He's one of the few where we have clear dates and effects.

During the 2007 season, Peralta saw himself bounce back to form, posting a translated EqA .022 points higher than his previous campaign. Furthermore, he improved his home run and ISO numbers by significant margins over the next two years. While there was some regression in 2009, the surface of his performance shows some hints in regards to the potential of LASIK improving player output.

LASIK surgery has become a spring training cliché over the last couple of years for players looking to create buzz and writers looking to have stories during the monotonous pre-season beats. Most quotes from players who've had the surgery say they will "be able to see the spin on the ball better" or "get a better read on the release point of the opposing pitcher." Thus, we can infer that a player who has had his vision significantly enhanced would be able to make contact with the ball more, swing at more balls in the strike zone, and/or lay off pitches that travel outside of the zone.

That leads us first to contact rates. With a disclaimer that we chose to include, the smaller-sized sample of the 2004 season during the following portions of the study is due to the fact that it does not fall outside of the overall form of the data. Below is a table for Peralta's contact percentage during his career, with the asterisks indicating the time the LASIK procedure took place:

Year   Pitches Contact%  # of Pitches Contacted 
2003    1054    73.70%           776.798 
2004     118    76.20%            89.916 
2005    2281    76.70%          1749.527 
2006    2606    73.50%          1915.410
----    ----     ---               --- 
2007    2545    76.90%          1957.105 
2008    2502    78.50%          1964.070
2009    2546    77.60%          1975.696 

Again, on the surface, the pre-surgery contact rates seem to be smaller than the post-surgery rates. This fact is reinforced by looking at the numbers visually:

Chart 1

Oh, but there's more. As sexy as graphs look, we're not going to be able to tell if the change in contact rate is really significant until we do a statistical test. For our purposes, we'll use a 2-Sample Proportion test. This method will allow us to see whether or not the change in contact percentage is really significant. Using the mean pre- and post-LASIK contact rates as our tested proportions, a deeper statistical look gives us this:

Test and CI for Two Proportions

Sample    X    N    CONTACT % 
   1    4532  6059  0.747978 
   2    5897  7593  0.776636 

Difference = p (1) - p (2) 
Estimate for difference:  -0.0286582 
95% upper bound for difference:  -0.0165757 
Test for difference = 0 (vs < 0):  Z = -3.92  P-Value = 0.000 
Fisher's exact test: P-Value = 0.000

The number we want to look at here is the P-Value. This value indicates to us the chances that, given that performance before the offseason of the LASIK surgery should be equal to the performance after the offseason, we observe a contact rate that is more extreme than the contact rate posted in the 2007-2009 seasons. The lower the P-Value, the more support for the significance of our results. Since we received a P-Value of 0, we can conclude that something fairly significant happened during the 2006-2007 offseason. Was it LASIK? We don't know for sure, but let's look at some other factors that could have been effected by the procedure.

Next, let's look at Peralta's Zone Contact %, the percentage of times he made contact with a pitch that was inside the strike zone. If Peralta could see much better from 2007-09 than he could from 2003-06, we'd expect that he would make contact with higher-quality pitches, a.k.a. strikes (or non-balls) more often during his post-surgery tenure. Here are the numbers:

        Pitches     Contact
Year  In the Zone   In Zone    Z-Contact% 
2003    529.108     447.625     84.60% 
2004     60.180      49.588     82.40% 
2005   1220.335    1055.590     86.50% 
2006   1370.756    1129.503     82.40% 
2007   1303.040    1120.614     86.00% 
2008   1268.514    1092.191     86.10% 
2009   1239.902    1058.876     85.40%

Again, we can see the dip in 2006 and significant rise in overall zone contact rates from 2007-2009. More sexy:

Chart 3

Once more, we have our suspicions confirmed by a graph. The interesting thing here is the volatility of the pre-surgery numbers compared to the post-surgery. Even when one excludes the 28 PA season in 2004, Peralta's Z-Contact percentage is all over the place, while the post-surgery numbers are not only high, but also consistent.

Using the ever-useful 2-Sample Proportion Test, we will now test if the change in Z-Contact percentage has been significantly raised during Peralta's post-LASIK seasons:

Test and CI for Two Proportions

Sample    X     N   Sample P 
   1    2683  3180  0.843711
   2    3272  3811  0.858567

Difference = p (1) - p (2)
Estimate for difference: -0.0148566
95% upper bound for difference: -0.000771322
Test for difference = 0 (vs < 0): Z = -1.74  P-Value = 0.041
Fisher's exact test: P-Value = 0.044

As we can see, our P-Value is significant at the 5-percent level, or is below .05. Most stats 101 classes will tell you that .05 is the benchmark number in which one would want their P-Value to be below if statistical significance is observed. Thus, the conclusion can be made that the difference in Z-Contact percentage is significant. While we're unsure is LASIK has anything to do at all with this change, it wouldn't be a stretch to believe there would be some partial influence there.

Finally, we wanted to take a look and see if Jhonny stopped swinging at bad pitches, a.k.a. pitches out of the zone, at a better clip than his pre-LASIK days, denoted in this article as OOZ Swing % (Out Of Zone Swing Percentage). Here are the numbers regarding that (Disclaimer: I decided to exclude the 2004 season due to the its small sample size and potential influence on this portion of the study):

Year  OOZ Pitches    OOZ Swings  O-Swing% 
2003    524.892       137.5217   26.20%
2005   1060.665       197.2837   18.60%
2006   1235.244       261.8717   21.20%
2007   1241.960       305.5222   24.60%
2008   1233.486       345.3761   28.00%
2009   1306.098       342.1977   26.20%

Once more with the sexy chart:

Chart 2

The graphical method shows something very odd: Peralta is actually swinging at more potential OOZ pitches in his post-surgery period than his pre-surgery period. Whether LASIK has something to do with this or he has simply become more aggressive with age, Peralta is taking more hacks at traditionally unfavorable pitches than ever before. Of course, a question we should ask would be: Is this change in OOZ Swing Percentage statistically significant? Let's take a look:

Test and CI for Two Proportions

Sample   X     N   Sample P 
   1    607  2879  0.210837 
   2    994  3782  0.262824 

Difference = p (1) - p (2) 
Estimate for difference: -0.0519868 
95% upper bound for difference: -0.0348123 
Test for difference = 0 (vs < 0): Z = -4.92  P-Value = 0.000 
Fisher's exact test: P-Value = 0.000

Indeed, the rise in OOZ Swing Percentage is very significant. How paradoxical, eh?

Several small-scale studies, like this one, have tried to determine whether or not LASIK surgery has positive effects on players, but there's still no definitive study that would tell us how much, if any, difference it actually makes. While the results have varied, it seems fairly plausible that Peralta probably received some benefit from the LASIK procedure. However, given the wide range of outcomes from players who have had the surgery and because we cannot isolate out other significant variables like age, we can't make any definitive statements.

This all jibes with the 2004 findings of Matthew Namee. Most testing done for LASIK efficacy is focused on simple vision and the lack of "artifacts"-the visual effects, such as halo and ghosting, which are side effects of the procedure. It's no surprise that there's little done in what is a tiny fraction of LASIK cases. Without more data, we're left hoping we can quantify the effects beyond a wide but insignificant range. In fact, while the "why is LASIK all right but steroids aren't" argument actually looks a bit interesting here since both have problems of date, intent, and player quality. No one goes from has-been to All-Star. There's not even a single Henry Rowengartner-style outlier.

So how, then, do we test it? There's nothing like turning yourself into a guinea pig. I'll be having wavefront-guided LASIK surgery at the end of the month. Before and after the surgery, I'll be undergoing a vision test not unlike those used by major leaguers. The first will be the simple before and after testing done by the surgeon. Then, I'll be taking a computerized vision assessment, one that will not only focus on visual acuity, but reaction time and recognition skills. This also will be done before and after. Finally, I'll be standing in the batter's box at Batter's Edge, using specially designed balls. Many teams use this as a drill, using colored dots. Ours will use small numbers, since besides being far-sighted, I'm also a bit colorblind. I'm certainly no major-league hitter, but this is something that we can control. For one man, at least, we'll know just how much of an improvement LASIK surgery is and whether baseball players are truly getting an advantage, or just getting rid of contacts and glasses.

Dan Wade and the 20/20 Institute in Indianapolis provided assistance for this column.

Related Content:  The Who,  Surgery,  Visual,  Sample Size,  Significance

43 comments have been left for this article. (Click to hide comments)

BP Comment Quick Links

Nathan J. Miller

While his OOZ swing percentage is up... it looks like so is his OOZ contact rate... is it possible that this reflects he's swinging at more outside-zone pitches, but that they're pitches he can drive? Just eyeballing the data on fangraphs, outside contact rate looks like it rose more-quickly that outside swing rate...

Jan 22, 2010 09:31 AM
rating: 3

lol @ "eyeballing"

Jan 22, 2010 19:00 PM
rating: 0
Other readers have rated this comment below the viewing threshold. Click here to view anyway.

Another comment eaten by the comment box. I'm so f'n tired of that. I'm too pissed to even bother trying to retype it.

Jan 22, 2010 10:00 AM
rating: -30

Just a point of interest - this topic has already made its way into the medical literature and I have attached the reference and abstract below. Its an interesting paper, although the baseball statistical analysis component is not very sophisticated. There are also several papers looking at visual acuity, ocular dominance, reaction times, depth perception, and others in both major and minor league baseball populations.

Here is the reference and abstract:

Optometry. 2005 Nov;76(11):647-52.

The effect of laser refractive surgery on the on-field performance of professional baseball players.
Laby DM, Kirschen DG, De Land P.

Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston, Massachusetts, USA. drlaby@drlaby.com

BACKGROUND: The aim of this study was to determine the effect of laser refractive surgery on the offensive performance of professional baseball players. METHODS: Extensive search of the public media was conducted to determine which major league baseball players had undergone laser refractive surgery and when the procedure was performed. Baseball performance data were then used to determine presurgery and postsurgery baseball performance averages. A total of 17 position players were identified; however, 5 of these players were not considered in the analysis owing to insufficient playing experience either before or after the laser procedure. RESULTS: No statistically significant or practically significant difference was found between the presurgery and postsurgery means on either on-base percentage (P = 0.31), batting average (P = 0.39), slugging percentage (P = 0.66) or on-base plus slugging (OPS; P = 0.997) of major league baseball players. CONCLUSIONS: These preliminary findings suggest that professional baseball players should not expect a laser refractive surgical procedure to significantly improve their offensive baseball performance, despite the elimination of glasses or contact lens wear.

Jan 22, 2010 10:21 AM
rating: 2
BP staff member Chase Gharrity
BP staff

We actually referenced that study while trying to determine what our course of action will be in terms of methodology. With some of the great data being collected using Pitch F/X, we decided that going with Contact Rates / OOZ Swing % would be the most interesting route.

Jan 22, 2010 10:49 AM

Gee, a null result in a study with an n of 12. How on earth did this get published??? (FWIW- I'm an academic researcher in a different field and could never get away with bad science like that)

Jan 22, 2010 14:41 PM
rating: 5
Fresh Hops

A problem with that study is that all of those stats are highly dependent on the player's batted ball results which are know to require large samples for significance. While I can't judge whether that was a factor, it seems to me that DIBS (defense independent batting statistics) should have been used. Contact rates are especially suggestive, since we don't know how a hitter will respond to zone versus o-zone pitches if he can see them better. (I.e. a player might walk less because he swings more, might strike out more because he swings more, etc.) However, presumably, he will make more contact in each group if his visual accuity is improved.

Another potential flaw is that some players may have LASIK despite not needing it.

Jan 22, 2010 16:10 PM
rating: 0

James Loney had LASIK a couple spring trainings ago. Would be interesting to do this same examination on him.

Jan 22, 2010 10:26 AM
rating: 0

Cristian Guzman had the procedure done after the 2005 season and (like Peralta) immediately showed a dramatic and sustained increase in both his O-Swing and O-Contact rates as well his ISO.


Jan 23, 2010 13:57 PM
rating: -1

If I'm not mistaken, Greg Maddux had Lasik surgery. I'm not sure what the added benefits would be for a pitcher but I guess that would be another column.

Jan 22, 2010 10:28 AM
rating: 1

how many LASIK failures among MLB players have there been?...Brian McCann comes to mind, and he had round 2 of LASIK in the offseason...hopefully the second time will go better than the first time for him

Jan 22, 2010 10:28 AM
rating: 1

Interesting article. I wonder what % of ball players have had the procedure done? Or if there's vision related data on older ball-players. Eye sight must play a large role in separating great hitters from poor / mediocre ones.

One minor editorial note - you're last two graphs don't match the data given above the graph - the graphs should be flip-flopped.

Jan 22, 2010 10:33 AM
rating: 0

Will--this was really excellent

Jan 22, 2010 10:41 AM
rating: 3

A more sophisticated way to take a look at this question would be to use a repeated measures ANOVA. Using a BACI design (before, after, control, impact) and adding similar players who didn't receive LASIK as a control would be more appropriate. That would essentially keep track of an individual's ability to make contact, rather than lumping them together in a single average. With such a low P value, I doubt it would change the results of the analysis though.

Jan 22, 2010 11:10 AM
rating: 3
Al Skorupa

Will, this was an excellent article. This is exactly the sort of stuff I was hoping to see more of from BP. Keep up the great work.

Jan 22, 2010 11:20 AM
rating: 5
John Carter

This is a nice step, but this sure is a teensy weensy teeny tiny sample size. Any number of things could have led to one player's improved contact rate. The most obvious is that there is no control for Peralta's age and improved experience. After the 2006 season, he would have been 24. At the very least, we need to subtract the normal increase in contact rates that 24 year olds have (whether it is positive or negative) from the one found here.

Good luck with the procedure, Will. My sister had horrible eyesight before, now it is fantastic.

Jan 22, 2010 11:25 AM
rating: 3
BP staff member Will Carroll
BP staff

Yeah, it's tiny. The problem, as I said, is in getting the data on who had it and when. Most of it happens in the off-season, so the date itself isn't so much the key, but less data = more sample size issues. Factor in aging patterns and all the other variables and its very, very tough. All we're trying to do here is establish that maybe there's an effect. We'll go more into the science of how it works and try to get a bit more of a "why" in the next couple pieces.

Jan 22, 2010 18:26 PM

Good article Will. I find this funny though, in that LASIK wasn't around in the 70's, 80's & 90's. Isn't that a competitive advantage that players today have over others of previous generations? We should outlaw LASIK then, right?

I probably haven't done this well enough, but what the point I'm trying to bring up is - what if HGH is in fact something that makes you healthier, live longer, be stronger, etc.? It will probably help you play into your 40's. It will help you come back from injuries quicker - potentially.

So, how is someone taking HGH different from someone getting LASIK because their eyesight is getting bad?

I'm not necessarily supporting HGH use - too much needs to be tested first. But, if there were no serious side effects/harm, why would it be banned but LASIK, Tommy John Surgery, etc. isn't?

Jan 22, 2010 11:30 AM
rating: 6
Richard Bergstrom

Gray areas are always funny... players get beaned if they try to steal signs, but nothing happens if they watch video replays in the clubhouse.

In any event, the cardboard answer is that HGH is illegal and LASIK is legal. Kind of like how amphetamines are illegal unless you have a prescription for ADHD...

Jan 22, 2010 17:56 PM
rating: 1

i thought the key sentence in the article was that Peralta tried contact lens in the last month of 2006 and this improved his vision.

I'd surmise from that his eyesight was less than 20/20 to start with, so it can't reasonably stated this was due specifically to LASIK surgery itself. I mean, perhaps he would have shown the same improvement with staying with contacts or presrciption glasses (?)

I think to properly evaluate, you need data on players who wear prescriptive lens, THEN switch and have LASIK surgery.
Going straight from nothing to LASIK to me is just like going straight from nothing to glasses - it's obvious it'll improve tour eye sight and the ability to play ball.

Jan 22, 2010 11:36 AM
rating: 10
BP staff member Will Carroll
BP staff

I'm going to agree but disagree here. You're right in the broad sense, just like I could just start wearing contacts if I wanted. Same result, but I hate how contacts feel in my eyes and I'm terrible at putting them in. Imagine a player who didn't like how glasses or contacts felt. This is as close to "normal" as can be had currently, intermediate steps or no.

Jan 22, 2010 18:28 PM

There was a player I knew in the low minors who could crush fastballs, but could not pick up the curveball. Turns out he had bad vision. The team got him glasses, but he lost them after a few weeks. He was a very poor caribbean youngster and never replaced them. He washed out of baseball after that year.

If he had gotten LASIK (not that he could afford it or the team tended to pay for much), maybe his career would have been different.

I wonder long term if getting players LASIK in the low minors would work better, giving them more chance to adjust against lesser breaking stuff.

Jan 23, 2010 18:36 PM
rating: 0
Richard Bergstrom

I don't wear contacts but I hear they dry out your eyes a lot and your eyes get irritated easily, especially from dust. Since there's a lot of dirt in the infield and around home plate, with players sliding around and all that, I bet that if LASIK doesn't have the same irritation problems as contact lenses, that can help a player a lot.

Jan 28, 2010 21:59 PM
rating: 0
JD Sussman

I would like to agree with everyone else that this was a fantastic piece. I really enjoyed it from start to finish.

The only issue I have is n=1 and 1=Peralta. There are too many other variables that go on with players to really know the net gain/loss of the LASIK. As mentioned in the article, it is difficult to get a complete or even larger list of players with LASIK given the nature of elective surgery.

Hopefully in the future we can see how Peralta compares to other players whose information becomes available.

Jan 22, 2010 12:39 PM
rating: 0

Consider this an exploratory case study. I think that's all Will intended this as.

Jan 22, 2010 14:43 PM
rating: 2

good info... I hope BP steps up and pays for it. At the very least it will be a good tax write off!

Jan 22, 2010 13:35 PM
rating: 1

frickin sharks with frickin laser beams on their heads!!!!!

Jan 22, 2010 14:10 PM
rating: 0

Excellent article, although to my non-statistician eye, it looks like 2006 is the outlier, not the period before or after that season.

Jan 22, 2010 14:55 PM
rating: 0

An excellent little pilot study. Thanks, Will. And good luck with your procedure. I'm very curious to see what the results of your own experience is with regard to reaction time. Acuity, I expect will improve. Not sure I'd expect a change in reaction times, but recognition might. Really depends on the details of the study, and whether you are reacting to or identifying threshold or supra-threshold targets. Again, good luck.

Jan 22, 2010 18:27 PM
rating: 0
BP staff member Will Carroll
BP staff

Thanks, yeah ... so am I.

Jan 22, 2010 18:29 PM
Brian Kopec

Wouldn't a player be more likely to have LASIK surgery after a season in which he had a poor performance relative to expectations (even if the poor performance was due to luck)?

Wouldn't we expect that player to naturally regress toward his true talent the next season?

So I would expect, even if we had a large sample size, to see some artificial improvement for players who had LASIK.

Jan 22, 2010 19:37 PM
rating: 4
BP staff member Will Carroll
BP staff

Good point, but isn't that an improvement?

One of the things I'll talk about in the next piece is that most LASIK procedures don't aim for vision correction, but for vision improvement. 20/20 is the minimum threshhold for a "successful" procedure. 20/10 is often hit, though not a majority. That alone blurs the correction/enhancement line for me.

Jan 23, 2010 11:00 AM

"Good point, but isn't that an improvement?"

I'm not sure what you mean here, Will. I thought the point is to isolate whatever performance increase comes from the LASIK itself. Brian makes a great point that the sample of players who receive LASIK is biased because most of them will get the surgery after a relative down year, and that a subsequent improvement could stem from a return to form and have nothing to do with the procedure.

If you could get reliable data on old-timers getting the surgery like McGriff or Boggs, then you might have a better chance at isolating the effects of the surgery. After all, these players are probably having the procedure done to combat the general decline related to age rather than in response to a specific down year as with Peralta.

Ultimately, I'm not sure that this problem can really be overcome. This may not be an especially fruitful line of inquiry.

Jan 23, 2010 12:41 PM
rating: 2
keyser soze


There was a note in the Wall Street Journal (!) last summer to the effect that the "average corrected eyesight" of 101 players in the Red Sox organization was 20/11. Are you familiar with that study? I'd be curious about how wide a range there is, and how it corresponds to "good" and "bad" hitters.

Best of luck on your procedure.

Jan 24, 2010 07:17 AM
rating: 2
BP staff member Will Carroll
BP staff

Not that one, but there's an internal team study that I've seen but can't discuss. It would not surprise me at all to find out that the "average" MLB player had freakishly good vision.

Jan 25, 2010 12:11 PM
John Carter

It is about time we had vision stats right up next to height and weight - especially for prospects.

Jan 26, 2010 10:59 AM
rating: 0

Great work as usual Will, and I do hope that at some point the ethical question is explored a bit, as this is clearly "performance-enhancing" surgery. I'm not suggesting we put an asterisk on Fred McGriff's post-Lasik accomplishments, but one wonders if he would be a borderline HOF candidate if he had been only 5-6 years older. Much like Tommy John surgery, because this medical intervention has been sanctioned as acceptable, then it's unlikely to be controversial, but it's important to consider all factors when discussing the levels of performance achieved by players through medical procedures and protocols not available to players of earlier eras.

And best of luck on your procedure, my 66 year old father recently had some laser surgery done and he's been able to put away his glasses (for the most part) for the first time in his life.

Jan 24, 2010 15:29 PM
rating: 1

Kind of off topic, but I remember reading a few years ago that Brian Roberts starting wearing special contact lens that highlighted certain things, and I believe allowed him to see the baseball much better. I'd be curious to hear more about that in a future article.

Jan 24, 2010 20:45 PM
rating: 0
BP staff member Will Carroll
BP staff

The Nike contacts? You know, I haven't heard *anything* about those in a couple yrs.

Jan 25, 2010 12:09 PM

Denard Span had it a few years ago and he went from looking like a player doomed to stay in the minors to a legitimate leadoff hitter at the major league level.

Jan 26, 2010 08:41 AM
rating: 0
John Carter

I just read in the Berkeley Wellness Letter received in the mail today that LASIK surgery can cause dry eye.

Jan 26, 2010 11:00 AM
rating: 0

Indeed it can. I've been using eye drops every few hours for the 5 years following my surgery. Yet another reason why having improved visual acuity (ie, 20/20) after LASIK does not necessarily mean that a player will have improved overall quality of vision.

Jan 27, 2010 10:59 AM
rating: 0

Nice article, Will on a long overdue topic.

When I went under the laser myself in 2004 (and survived, thankfully), I was working as a biologist, and so I did some extensive research on the LASIK literature. My comments here reflect the state of laser eye correction research as of the end of 2004. There are some important things to note:

1. Laser correction does not guarantee 20/20 vision or better. So one cannot assume that all players who have had LASIK will have 20/20 vision or better afterward.

2. In general, the worse your vision is going into the procedure, the greater the likelihood of having regression or side effects. So, to do a thorough analysis of LASIK on baseball players, it would help to know how good/bad their vision was going in and how it was coming out of the surgery.

3. Typically, it takes up to a year for a person's vision to stabilize post-surgery. So, the season immediately following a player's surgery is not necessarily the best measure of the surgery's success.

4. While you may have 20/20 vision after LASIK, contrast sensitivity is usually worse, giving worse quality of vision. In fact, most laser surgery practices will warn you that you must consider this if your job depends on having very sharp vision. The amount of loss of contrast sensitivity varies with the individual. Also, it is usually most prominent immediately following the surgery and becomes unnoticeable to most by around 6 months. So, the benefit for a baseball player of not having to wear contact lenses must outweight the loss of contrast sensitivity in order for the surgery to be beneficial. While most people wouldn't notice the loss of sensitivity, if any, baseball players surely would.

5. LASIK is only one of several laser eye correction options available. Another common one is PRK, often used for people with very poor vision (including myself). It is not known if there is a significant difference in vision after LASIK vs PRK. On a cohort that depends to heavily on their vision, it would be interesting to see if there is a different in post-surgery performance between players who have had LASIK vs PRK.

Good luck with the procedure Will. It changed my life!

Jan 27, 2010 10:56 AM
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