Playing with seeing aids

[BETA POST to get the content out there, will build out if there's interest]

Some of the questions addressed below

* What happens to my tennis game if seeing / vision improves?
* Reversely, if I don't see well, what happens to my game?
* Should I play tennis with glasses or contact lenses?
* What happens when I start playing tennis with glasses?
* How does the magnifying effect affect my game?
* How do I go about finding the right seeing aid?

Seeing & tennis

For most of my tennis life, I have felt that 1) I had more of a "global perception" (is that an infinite extension of triple vision?), and 2) never really looked at (picked up?) the ball. After a bunch of thinking and research on that topic, I'm still not really sure if those are skills or deficits - or maybe a bit of both? But, when I recently found out that I'm farsighted (i.e. I can use some help seeing near), I thought I should try playing with seeing aids and see what would happen.

Up to this point, I've adjusted with "accommodation" - basically using eye muscle power to bend the lens. That's quite exhausting over time, and tends to get harder as you get older. Also, on court you probably want to keep your eyes relaxed and put that energy elsewhere...

To improve as a player, I'm constantly trying to assess elements of my game and benchmark it against others. In more recent years, I've been trying harder to demystify skills and find out why people have become good at something. For example, here are some things I've been wondering about that might relate to eyesight:

  • How do some other players put away balls with much more assurance, even though I have the determination, technique and practice to do so?
  • Why do some seem much more balanced?
  • Why do some appear much calmer, and why does the timing seem so much better?
  • Why do they seem more consistent in general, day in, day out?
  • Why do they seem to handle misbounces much better?
  • How do others pick up what the opponent is doing, e.g. for poaching?
  • Why do I seem to have a more of that "global perception" on court, and subjectively 0 focus on the ball?
Trying out seeing aids seemed like a good way to get some answers. I though I'd give both of the usual suspects a try, glasses and contact lenses.

Playing with glasses

Being far-sighted, the biggest change playing with glasses was the magnifying effect. Everything was suddenly nice and sharp, but also huge! For my values of roundabout +3 dioptrics, everything seemed 20-30% bigger. On court, that was the biggest adjustment to make, probably because brain & body were trained for decades to measure & react to distance of oncoming objects without that magnifying effect.

After a few practice sessions I did feel it would be net positive to play matches with glasses, rather than without a seeing aid. In the matches, I found that I was handling normal-pace balls pretty well, but often when I had to react quickly I'd make contact too early. The magnifying effect made my brain think that the ball was already there. There were a few frustrating and outcome-affecting situations, such as putting sitters on top of the net straight to the bottom. Returning fast first serves was tricky too. What helped me was triangulating the distance to the ball with other objects in my field of vision - such as my other hand, my neon-colored string, and maybe even the tip of my cap's visor. And of course a lot of repetition, especially where reflexes where needed (e.g. volley-volley).

Things people warn about in regards to playing with glasses are limited field of vision, the frame obstructing that field, and the glasses fogging up. The first two I didn't have problems with - probably because my head does keep turning towards the ball until its trajectory is locked in, and when the ball gets very close you can't really see it anyways. For months I never had a problem with fog, until of course I played the National Championships on indoor HarTru. That surface needs a lot of water, so humidity was pretty high. Every 10 seconds or so the glasses would fog up, and I could not see much at all - not fun. To counter, people seem to recommend anti-fog spray or keeping a layer of liquid soap on the glasses, which I haven't tried yet.

A positive experience of playing with glasses was being able to see really well what the other player was doing, even from one baseline to the other. So that meant earlier prep, improved anticipation, and with that better movement, timing, and balance. I felt how most of the microadjustments I had made over the years started to go away. I probably got looser overall too.

Bottom line, the brain does adjust over time and it's been nice feeling more stable and hitting the ball very cleanly. I find that magnifying effect bothersome though, and also would not like to get into another situation where the glasses fog up during an important match.

Outside of tennis, the magnifying effect bothered me too. For example, I did not like that the car gauges, a basketball, or even people's faces suddenly looked so huge. For working on the computer or watching TV it was pretty nice though, since everything was sharp, and in a sense you get a screen size upgrade.

Playing with contact lenses

Out of the gate, most people would recommend contacts for sports. I wanted to experience both though - out of curiosity, and to see what works better for me.

At first, I had trouble putting the contacts in, probably because our natural and often reinforced instinct is to protect our eye from foreign objects. In addition, the first couple of lenses I tried were not that comfortable.

The biggest problem though was that my local optometrist, part of a major chain, gave me weaker lenses compared to my glasses. After talking to a few others and doing research, you're supposed to do that for nearsighted folks. So those contacts helped a little bit, but neither felt effective nor natural. If you're far-sighted (again, you can see well into the distance and need help closer up), you'll at least need the same dioptrics numbers as you do for glasses.

A different optometrist gave me a demo pack of Bausch & Lomb's PureVision 2 in the right strength - in my case same as the glasses. I immediately saw great, and after a few seconds did not even notice wearing them anymore.

If optometrist and/or eye doctor agree, you can leave those 30 lenses in for 30 days straight, day and night. Looks like experts recommend taking them out for activities like sauna, swimming, or anything else that could affect hygiene, oxygen exchange, tear fluid etc. I'm surely not an expert here, just pointing out a few things to be cautious about.

Being on court felt pretty natural again, will have to play some more and see what happens. Jumping into a match right after playing with glasses for a few months was a bit tricky though. I expect the readjustment to take some time, however less than adjusting to playing with glasses :)

Takeaways, for now

In hindsight, I should have gone straight to (the right) contact lenses. Maybe go to 3 optometrists, see what they recommend, compare, and try things out. Demo packs seem pretty common too, so it probably won't hurt to pick up a few different contacts and see which ones work best.

Before playing with a seeing aid, it looks like I had taken on a bit of a Dare Devil challenge. Since vision was handicapped, I had to amplify my other senses. For example, I think I triangulated ball position and point of contact by picking up that oncoming trail of yellow, by sound and rhythm, and by building up a lot of experience over the years. Maybe that's also one of the main reasons why I can tell if a racquet 1 mm or 1 gram off, if the grip is 1 mm too thick, or if the string job did not turn out perfectly.

Tennis (and the rest of life) is definitely a lot more fun when you can see well. My hypothesis is that most players on top of their respective game have great vision - as seems to be the case with Roger Federer or Timo Boll.

Overall, playing without and with different seeing aids were valuable experiences. In theory those should have added some differentiated learning for brain & body, and will hopefully pay dividends in the long run. I'm curious and cautiously excited about feeling more comfortable on court, especially in matches. Will provide updates here once I learn more...

The tennis racquet spectrum

These days, it's thankfully easy to look up specs for individual mainstream racquets. One good resource is Tennis Warehouse (RF 97 example), who also offer their Racquet Finder to find racquets within custom ranges.

However, I haven't found a nice overview showing the current spectrum of what you can buy, so I took a first pass at creating one. The below charts are derived from roughly 250 frames that have been on the market over the last couple of years. The list is not comprehensive, but the decent sample size should give us a good idea of how the world of tennis racquets looks like.

Weight & balance (mm)


Graph of tennis racquet weight and balance correlatation

This scatter plot nicely shows the correlation between weight and balance. Generally, the lighter a racquet, the more head-heavily balanced, and the heavier, the more head-light. The general correlation here is that for every increase of 10 grams, the balance point moves down by about 5 mm.

On the heavy, more head-light end we find some classic-spec frames, such as the Wilson SixOne 95 or Roger's RF 97. Fully loaded, the stock RF 97 can come in over 360 grams. The lightest racquet I found on the market is the Donnay Superlite 114 at 238g, which is the outlier in the bottom left. So the spread here is about 120g, or a possible weight increase of up to ~50%.

In regards to balance, the most head light racquets are classic player's sticks like Pete's Wilson Pro Staff 6.0 85, the Völkl Power Bridge 10 Mid, and the Vantage BC20, all balanced at around 310mm. At the other end of the spectrum we mostly find game improvement / comfort racquets, such as the Head Titanium Ti.S5 Comfort Zone or Wilson Hyper Hammers, balanced at and even above 385mm. So we're seeing more than a 75mm range, or about 10% of total racquet length.

In the chart, we find the biggest cluster at around 325g and 325mm - probably a proven combo for players who have developed sound technique, and would like a versatile racquet allowing them to hit any shot in their repertoire. Good examples here are the Wilson Burn 95 FST, the Head Prestige Pro, or the Yonex Ezone Ai 98.

There's also a bit of a cluster around 280g and 350mm, where we find racquets such as the Dunlop Biomimetic S 3.0 Lite, the Head Graphene XT Speed REV PRO, and the Wilson Burn 100 ULS. Easy-playing racquets that should help develop more fluid swings and/or get the ball into the court.

Again, the biggest takeaway here is the correlation between weight and balance. The combination of the 2 lead to swing weight:

Swing weight (kg cm²)


Swing weight distribution of tennis racquets on the market

The max value at 412 is the Gamma RZR Bubba. If you look again at the weight / balance scatter plot above, you'll find it out on its own at roughly 300g and 390 mm. This combo leads to the highest swingweight of any mainstream racquet I found.

Min: 282 - Völkl Team Speed Orange, 283g and ~334mm.

Average: 317 (e.g. Babolat Pure Drive, Dunlop Biomimetic F5.0 Tour, Prince Textreme Tour 100T)

Median: 316 (e.g. Yonex Vcore Tour 97 310g, Wilson Steam 105S)

Note: You can even go deeper here by looking at twist weight and recoil weight. Those measures are harder to get and may be more interesting for high end players who also care about optimizing their racquets.

Length (inches)


Length distribution of tennis racquets on the market

The standard length of 27 inches / 68.58cm is still the most popular, represented in ~3/4 of the racquets on the market.

The 27.0 - 27.5 range is somewhat popular too, mostly for game improvement racquets. Examples for 27.5 are the Babolat Pure Drive 110, or the Wilson Blade 104 that could be interesting for two-handers.

Notables in terms of length are the Head Graphene XT Instinct Rev Pro that is a bit shorter at 26.8 inches / 68.07cm, and at the other end again the Gamma RZR Bubba @ 29 inches.

Head size (in²)


Head size distribution of tennis racquets on the market

Max: 137 - again the huge Gamma RZR Bubba.

Min: 85 - that's the Wilson Pro Staff 85 you can still buy today. Followed by more recent frames such as the Yonex VCORE Tour F 93 (=> 93 in²) or the Head Graphene XT Prestige Rev Pro (also 93).

Average: 101 (e.g. Völkl V1 Classic, Donnay Pro One 102, Head Graphene Radical S).

Median: 100, such as the Babolat Pure Drive, Dunlop Biomimetic M 4.0, Head Graphene XT Speed MP A, Wilson Juice 100 / 100 S, Pacific X Fast Pro, the Prince 100 racquets, and many others. Probably the "sweet spot" in terms of head size these days.

Stiffness / flex (RDC)


Flex / stiffness distribution of tennis racquets on the market

Max: 75, e.g. the Asics racquets, such as the 109 or the Head Titanium Ti.S6. The Wilson Juice 100S is up there too, at 74.

Min: 45. Vantage frames come in pretty soft below or around 50. Some of the softer mainstream frames are the Head MicroGEL Radicals (~56), the Donnay Pro One GT 18x20 (57), the Babolat Pure Control 95 (58), or the Wilson Blade 104 at 59.

Related note: Wilson Triad racquets feature gel inserts between the head and handle, resulting in a very low stiffness measures (around 17).

Average: 66 (e.g. Wilson Six One 97 and 97S, Yonex VCORE Tour F 97 (290g), Head Graphene XT Instinct MP.

Median: 67 (e.g. Babolat Pure Strike 16x19 (Project One7), Volkl Super G V1 Midplus, Prince Textreme Warrior 107).

Other racquet properties


... to think of are frame width, string pattern, grommets, and price. So some quick thoughts for now:

Width: 22mm beam width seems is pretty standard these days. More classic frames can be as thin as 18mm (e.g. the Pro Staff 95S or Roger's "old" Tour 90). Donnay made a comeback a few years ago with frames that were 15mm thin in some places. The Asics 125 or the Wilson Hyper Hammer 5.3 Stretch OS come in at 28mm, and the Prince Textreme Premier 120 marks the high end at 30mm.

String pattern: Recently, more open patterns have emerged to promote spin generation - if you see a 16x16 combo, or even less strings in any direction, you've probably found one. Classic patterns like 16x18, 16x19, or 18x20 are probably still the most prominent. PowerAngle racquets are somewhat interesting in this context, since they're strung diagonally.

Grommets: Over the years, many manufacturers have played around with grommets too, mostly aiming to increase the sweet spot. This has been done e.g. by trying to reduce friction, giving the string more room to move, or inserting some elastic material. In the last racquet generation, Wilson drilled the holes parallel into the frame, which seems to have worked well for the SixOne 95 that I had played for a while.

Price: New top brand racquets usually cost around $200, last gen racquets tend to be reduced to around $100, and current discounted or 2nd tier brand racquets are around $150.

So there you go, for now. Maybe this can help you find the right racquet, save some money by buying a previous generation, and push the industry to innovate beyond the usual variables...

Happy to rework or tweak this based on feedback and interest. Cheers!

Solinco Tour Bite gauge comparison

After playing the Tour Bite 1.25 for a good while and occasionally ending up with arm pain, I started looking at the 1.20 and 1.15 mm versions, as they are significantly softer / less stiff. I ended up ordering all 3, and strung up my 3 SixOnes @ 21/20 kg for a direct comparison:

3x Wilson SixOne 95 with Solinco Tour Bite in different gauges

My playing impression was that both thinner gauges are playable, even for someone like me who's been committed to 1.25 mm. I was mostly concerned, but also curious about the 1.15 mm. That one surprised me by not feeling as tinny as I had expected. Overall, the 1.15 immediately appeared familiar and quite predictable to me. The only noticeable downside was that it swallowed a good amount of power, which I first noticed by watching my overheads dying off a bit, versus going though the court.

As one would expect, the 1.2 mm does fit between the 1.25 and 1.15, however it doesn't sit straight in the middle. Compared to the 1.25 you get an over-proportionate drop in stiffness, but in terms of feel it seems to stay closer to the 1.25 than move towards the 1.15. This is confirmed by TW's string data:

Gauge (mm)Stiffness (lb/in)Spin Potential
1.15161.75.8
1.20181.26.3
1.25237.75.9
1.30202.96.7

According to TW, the 1.15 is actually 1.18 mm thick, the 1.2 is 1.23 mm, and the 1.3 is 1.34 mm. That also helps to explain why the 1.2 felt close to the 1.25, and the 1.15 didn't feel too thin.

So how to choose a gauge? Some thoughts:

* If you *are* looking for stiffness, the 1.25 is clearly for you. Subjectively, the ball grab is the strongest I've experienced so far, producing not only vicious spin, but also providing confidence in match play.

* If you like thicker gauges, the 1.3 can give you a boost of spin, and I would assume power too. I could see the 1.3 doing well in a Pure Drive, or some other >= 22 mm beam frame with an open pattern.

* The 1.2 now seems like a compelling all-around option, and thus maybe the best Tour Bite to try first. It's probably most interesting for all-court players wielding a player's stick, for example a current Prestige Pro, Blade, Pro Staff.

* The 1.15 might be an interesting option for finesse players - it might do well in a 18x20 control frame such as a classic Prestige or - loosely strung - in control-oriented Yonex like the VCORE Tour F 97.

So that's some directional info. I have been blasted off the court by a 1.15 a couple of times, meaning other combos are surely possible as well. My takeaway from this comparison is that I'll likely give the 1.2 another go sometime in the near future...

RelatedComparison of interesting strings in 2016