How to Incorporate Sports Vision Into Your Practice

Optometric Management, Jun 2006 by Kirschen, David G, Laby, Daniel M

Part 2 of our two-part series explains how to add this specialty to your practice, as well as how to correct and enhance athletes' vision.

As we reviewed in Part I, the vision capabilities of athletes far exceeded those of the general population. Therefore, phrases like "that's close enough," or your vision is "pretty good," are not applicable to the sports vision world. The key word in all sports vision correction is optimization.

Optimizing vision

The basis for all vision tasks is acuity. Therefore, for any part of the visual system to work optimally, the patient's refraction must be exact (not close, but exact). Your refracting technique should continue until each athlete's vision is optimally corrected. Small corrections for astigmatism (both power and axis) are critically important to athletes. Corrections like +0.25D, -0.50D x 117 are not uncommon and when you demonstrate the Rx to the athlete in a trial frame, it can noticeably improve their vision.

Binocular balance is another critical aspect of the refraction. The goal of refraction is not to optimize the visual acuity in each eye separately; rather it is to equalize the accommodative effort in each eye so the two eyes work better together. We will deal with optimizing binocularity in the next section, but as a precursor, the patient must be wearing a balanced prescription. There are many good techniques to binocularly balance a prescription (i.e., Turville or R/G dissociation). Use the one that works best for you, but do use one.

We alluded earlier to demonstrating the new prescription to the patient in a trial frame. This is also an important step for optical and psychological reasons. Optically, it gives you another opportunity to refine the spherical component of the refraction when the patient is looking in free-space rather than behind the phoropter. Binocularly adding +/-0.25D with flipper lenses gives the patient another chance to refine the distance prescription. Psychologically, this is important for the patient. Many athletes think their eyes are "perfect." By demonstrating that a correction (notice we didn't say glasses) can improve their vision, they will be more willing to accept your recommendation that a correction is necessary for optimal sports performance. The patient's specific needs and your diagnosis will determine whether contact lens or spectacle correction is best.

Stereopsis

Distance Stereopsis is the second major component related to sports performance; this visual function must be optimized as well. The Smart System ProSports Screening system measures both contour and random dot stereo thresholds. Sub-optimal performance usually occurs due to a lack of familiarity with the distance stereo tests or central suppression. Prescribe vision training for any athlete who does not perform well on distance stereo measures.

Most of the training techniques to enhance Stereopsis and reduce central suppression are done at near. Most stereo training done at near transfers to distance viewing, but vectograms mounted on an overhead projector provide a good distance target to train Stereopsis. You can use classic vision therapy equipment, as well as computerized vision training programs. Re-test to monitor progress. If an optical correction is necessary, be sure that the patient wears the correction during all exercise sessions.

Contrast sensitivity

Enhancement of contrast is still an area of intense study. There have been numerous anecdotal reports that wearing yellow filters may improve contrast for baseball players (e.g., Mark McGuire) and target shooters. The reports continue even today with the introduction of Bausch & Lomb's new Maxsight contact lenses, advertised to enhance contrast.

We are awaiting scientific published data to substantiate this claim. We have measured the change in contrast with yellow filters for white targets on a blue background and found a significant increase in contrast sensitivity for about 33% of players tested. On the other hand, about 33% of players had a decrease in their contrast sensitivity with the yellow filter, so use care when prescribing a filter to enhance contrast.

There is currently a study underway to determine whether onfield performance changes with the filters. If you wish to understand the importance of filters on contrast sensitivity for a particular athlete, test the player's contrast sensitivity with and without the filters to see if there is a demonstrable difference. Onfield testing is also appropriate before prescribing.

Hand-eye coordination

There are other, more general exercises that involve hand-eye coordination or visual reaction time that could enhance a player's visual performance and help the on-field performance. However, these techniques have been difficult to quantify.

One technique that has worked well for our players is the use of a hoop and specially-designed balls. Ask a player to grab a specific ball as it rotates toward him on the circular hoop. For the laymen this is a very difficult task. For the average baseball player, this is a doable challenge; for the elite hitter, the task is quickly mastered.