In the previous two videos, we’ve discussed much about how vision plays such a crucial part in the success of hitters. In this video we define what vision really is and put in practical terms in how vision can either aid or prevent the success of a hitter.
First, the term “vision” is sort of a misnomer. The definition of “vision” is simply the ability to see but it doesn’t include any parameters or measurements on what constitutes good or bad vision. The correct definition of measuring vision is called “visual acuity”, and is the ability to see details. This is commonly known and measured by ones visual prescription such as 20/30, 20/20, etc., derived from the Snellen Eye Chart (see below)
Snellen Eye Chart
To put it in simpler terms, if vision is being able to simply see the forest, then visual acuity is the ability to see the trees, branches or leaves. There is an old hitting adage that states,” You can’t hit what you can’t see”. This is very true but it deals vision on an almost superficial level. In my opinion, it should be updated to, “you won’t hit well what you don’t see clearly”. Now we’re dealing with visual acuity and the ability to see detail in the pitch.
Before I go further I want to explain how visual acuity is measured and what the numbers actually mean. When I’ve trained hitters in the past, I’ve asked them to define 20/20 vision. Typically, the answer I will get is that “20/20 is perfect vision” and they’re guessing as to what numbers actually represent. I saw this as a big red flag because I realized any discussion on visual acuity and vision training was going to be limited if the hitters didn’t first know what constitutes good or poor vision.
First 20/20 is not perfect vision. It is normal vision and the layman’s definition is that if you have 20/20 vision, you will see the same clarity and detail at 20 ‘ as a normal person will see at 20’. Conversely, someone with 20/30 vision will see the same clarity and detail at 20’ that a normal person (20/20 vision) will see at 30’. And finally, a person with 20/15 vision will see the same clarity and detail at 20’ what a normal person (20/20 vision) at 15’.
I know the previous paragraph may have gotten confusing, so I’ve added a table below to summarize it all:
I felt it is important to provide a definition of visual acuity in this discussion because I have found thru experience that hitters tend to have a lack of knowledge about their own eyesight. Whether it be thru oversight or lack of knowledge, I have found that a significant percentage of hitters I’ve talked to lacked an appreciation and/or knowledge about their own vision. Basically it comes down to that they don’t know what they don’t know. This is not meant as a slight to any of them. I just believe they haven’t been exposed to how critical optimum eyesight is to being a successful hitter. Nor have they been exposed to a comparison of their vision with a better visual acuity (i.e. they have no baseline for comparing their visual acuity).
For instance, if you look back at the Snell Eye Chart, you will see line 6 is 20/30, line 8 is 20/20 and line 9 is 20/15. These prescriptions are just minimally different from each other. In your daily life you probably wouldn’t know the difference between them and could function just fine. However, in the context of hitting a baseball (or softball), these minimal differences play a huge role.
As we show in this video, if you extrapolate the visual acuities listed above to a 60’ distance (mound to plate), significant deficiencies arise at a prescription of only 20/30. In this case, the same detail and clarity a person with 20/20 visual acuity sees out of the pitchers hand (60’) will be seen at 40’ for a person with 20/30 visual acuity. Think about that for moment: A hitter with 20/30 visual acuity, which is a just a slight visual deficiency, has just given up 1/3 of the flight path of the pitch (20’) before they can see the equivalent detail. And this doesn’t even account the pitch velocity!
Let’s now factor in pitch velocity. A 90mph fastball typically takes +/- 0.4 sec from release point to the hitting zone. Using the above example, the hitter has just given up +/- 0.13 sec. In essence, a hitter with 20/30 vision is hitting at little league distance.
As you may deduce from the discussion above, it is my opinion that visual acuity plays a very significant role in the success or non-success of a hitter before they even step in the box. But I also thought it was very important to educate hitters on how their visual acuity impacts their chance of success as well as arm them with knowledge so they can achieve their optimal visual acuity in conjunction with their eye care professional through corrective measures (i.e. glasses, contacts etc.), if need be.