[A comparison of Chinese reading parameters among rapid serial visual presentation, full screen and printed displays].

Objective: This study investigated reading speed of Chinese in rapid serial visual presentation (RSVP), full screen and printed display among young adults with normal vision. The critical font size and critical acuity reserve in RSVP were also evaluated.

Methods: Thirty university students with a visual acuity of at least 20/20 in both eyes (uncorrected or corrected) were recruited in this study. The visual acuity threshold (VAT) (3 m distance) was evaluated for all subjects using a self-designed visual acuity chart presented on a computer screen. The reading speed for Chinese was measured under RSVP (10 font sizes from 4 to 33 pt), full screen and printed display (2 font sizes: 10 and 13 pt). The reading speed (wpm) was expressed as the percentage of words read correctly x 60 x total number of words/time used (second). The acuity reserve (RA) was expressed as RA = SP/ST, where SP was the font size of the reading material for the reader and ST was the acuity threshold expressed as a font size.

Results: The visual acuity threshold (VAT) at a distance of 40 cm in these 30 subjects was (2.2 +/- 0.3) pt (mean +/- SD). The reading speed increased significantly with the increasing font sizes until the font size reached (7.8 +/- 0.4) pt where the maximum reading speed (258.0 +/- 34.4 wpm) was achieved. The reading speed remained at a constant value in font sizes ranging from 7.8 to 33 pt. The reading speed increased with the increasing R(A) until the R(A) reached 3.5:1 and then remained unchanged. There was no significant difference in reading speed between full screen and printed displays (P > 0.05). The reading speed in full screen or printed display was significantly faster than in RSVP (10 pt: full screen display versus RSVP: t = -10.15, P < 0.01; printed display versus RSVP: t = -8.77, P < 0.01. 13 pt: full screen display versus RSVP: t = -11.64, P < 0.01; printed display versus RSVP: t = -10.79, P < 0.01).

Conclusions: Young readers who use the computer as a reading tool can achieve a maximum reading speed for Chinese when the font size of the reading text is larger than 7.8 pt. A font size of at least 3.5 times the acuity threshold can attain a maximum reading speed for RSVP.