A study of static, kinetic, and dynamic visual acuity in 102 Japanese professional baseball players

Figures & data

Figure 1 Dynamic visual acuity (KOWA Co. Ltd., HI-10).

Note: The largest number of revolutions per minute (rpm) at which the subject can correctly identify the target (the gap in the Landolt ring) moving from left to right or from right to left on a screen situated at a fixed distance in front of the subject.

Figure 2 Kinetic visual acuity (KOWA Co. Ltd., AS-4).

Note: Decimal visual acuity converted from the measured size of the Landolt ring correctly seen by the subject as it lineally approaches the subject from a distance at a speed of 30 km/hr.K. Hoshina, one of the authors (corresponding author), is measuring KVA of a player.
Abbreviation: KVA, kinetic visual acuity.

Table 1 Stratification of players according to their performance level (Groups A, B, and C)

	No. of Players	Mean age	Age distribution	Pitchers	Fielders	Players without corrective visual aids	CL wearers
group A	28	29	19–40	15	13	16	12
Group B	34	26	19–37	15	19	27	7
group C	40	23	19–38	19	21	30	10
Total	102	26	19–40	49	53	73	29

Notes: Group A, players who had been on the roster of the top-level team all the time; group B, players who had been on the roster of the top-level team sometimes but not all the time; group C, players who had never been on the roster of the top-level team.

Abbreviation: CL, contact lens.

Figure 3 Dstribution of Eva and appropriateness of CL correction.

Notes: CL correction seemed to be generally appropriate.
Abbreviations: SVA, static visual acuity;CL, contact lens.

Table 2 Comparison of Eva, KVA, and DVA among player groups at different performance levels

	All		Group A		Group B		Group C
Comparison of SVA (logarithmic visual acuity)
n	102		28		34		40
Mean	0.089		0.106		0.097		0.064
SD	0.009		0.013		0.018		0.015
Comparison of KVA (logarithmic visual acuity)
n	102		28		34		40
Mean	−0.053		0.066		−0.041		−0.054
SD	0.019		0.034		0.038		0.029
Comparison of DVA (grades per second)
Direction	Left → right	Right → left	Left → right	Right → left	Left → right	Right → left	Left → right	Right → left
n	102	102	28	28	34	34	40	40
Mean	268.2	267.6	268.8	268.8	268.2	264.6	267.6	268.8
SD	0.316	0.35	0.595	0.321	0.441	0.689	0.591	0.573

Note: There was no statistically significant difference among groups A, B and C

Abbreviations: SVA, static visual acuity; KVA, kinetic visual acuity; DVA, dynamic visual acuity; SD, standard deviation.

Table 3 Comparison of KVA between pitchers and fielders (logarithmic visual acuity)

	All	Pitchers	Fielders
n	102	49	53
Mean	−0.117	−0.158*	−0.080*
SD	0.158	0.027	0.021

Notes: *Statistically significant difference between the pitchers and the fielders; t-test (P < 0.05).

Abbreviations: KVA, kinetic visual acuity; SD, standard deviation.