The Future of High Performance Visual Acuity
BY LEO SEMES, OD, FAAO
Refraction is a keystone of the eyecare profession. While this department is titled “Treatment Plan” and often involves the application of therapeutic measures to specific situations, eyecare practitioners should not lose sight of this mainstay of primary eye care. A correct refraction also serves as the basis for contact lens fitting and future modifications that may occur from contact lens wear or physiological changes.
I want to share the case of a patient who desired improved visual acuity. He was a wide receiver who wanted to see the grain on the ball as he tried to catch it.
The Player’s Profile
His medical, familial, and ocular histories were non-contributory. He took no medications on a regular basis and reported no allergies. Entering unaided visual acuity (VA) was 20/15 in each eye. I informed him of his above-standard VA, but he asked whether I could improve it.
Retinoscopy and refraction were both –0.25D sphere in each eye. To my surprise, his VA improved (to 20/10). Applanation tonometry was in the normal range. Anterior and posterior segment examination was normal in each eye.
We discussed his situation and potential options. I recommended that he wear frequent replacement contact lenses for practice sessions and games, and he agreed. I don’t know whether his statistics ultimately improved following this refractive treatment.
What Are the Lessons?
We know that the Snellen chart was developed in the 1860s by the Dutch ophthalmologist Hermann Snellen (Wikipedia). As we all know, it has limitations beyond its age. Snellen acuity measures a limited range of vision parameters and presents only high-contrast letters and symbols.
Dynamic visual acuity would be a consideration in this case due to football’s speed. A report that evaluated static and kinetic visual acuity among professional Japanese baseball players found no differences among the measures for all levels (Hoshina et al, 2013). Perhaps patients and practitioners should not expect performance improvement despite the specification improvement to 20/10.
Faster reaction times were positively correlated among baseball players with higher batting average (Classé et al, 1997). Dynamic visual acuity among drivers and older individuals whose vision may be impaired by cataract/glare as well as ocular surface irregularities have been studied and reported, for example (Marrington et al, 2008; Goto et al, 2006).
Future metrics may include dynamic and kinetic visual acuity measures that have yet to mature. In addition, the prospect of aberration correction will likely become more significant as the potential for vision beyond 20/20 is realized. This is an area for professional intervention that has been only minimally studied, and sports vision may be the place to start (Zimmerman et al, 2011).
With improved means of refraction and newer lens materials, we are poised to fulfill the desires of patients such as the young player described above. CLS
To obtain references for this article, please visit http://www.clspectrum.com/references.asp and click on document #215.
Dr. Semes is a professor of optometry at the UAB School of Optometry. He serves on the advisory board or speakers bureau of Alcon, Allergen, Optovue, Med Op, Merck, and B+L.