The Relationships Between Blink Rates Before, During Perimetry and Perimetry Reliability

Perimetry
was performed using the Humphrey Visual Field Analyzer II (model 750) with the
Swedish interactive threshold algorithm (SITA) standard strategy, the 30-2
program, and a size III white stimulus on a white background (equivalent to
31.5 apostilbs). The fixation loss, false positive, and false negative rates
were used to assess the reliability of perimetry.

(A)
Data for patients with dry eye. (B) Data for normal control subjects. Group 1;
eyes with decreased blink rates during perimetry in patients with dry eye;
Group 2; eyes with increased or unchanged blink rates during perimetry in
patients with dry eye; Group 3; eyes with decreased blink rates during
perimetry in normal control subjects; Group 4; eyes with increased or unchanged
blink rates during perimetry in normal control subjects.

Pre-perimetry
blink rates in the eyes with blink rates that decreased during perimetry varied
from 3 to 44/min in patients with DE (Group 1) and from 4 to 48/min in normal
control subjects (Group 3). Blink rates before perimetry in the eyes with blink
rates that increased or remained unchanged during perimetry were < 17/min in
patients with DE (Group 2) and 19/min in normal control subjects (Group 4),
respectively (Fig 1). Blink rates during perimetry were significantly lower in
Group 1 compared to Group 2, and in Group 3 compared to Group 4: Group 1, 4.6
(1.7-7.0 [0-21]) vs. Group 2, 13.4 (11.4-16.0 [2-39]) /min and Group 3, 2.6
(0.9-5.4 [0-12]) vs. Group 4, 20.1 (11.0-30.5 [4-36]) /min (P=0.007 and
P<0.001, respectively).

Fixation
loss rate was significantly higher in eyes with decreased blink rates among
patients with dry eye (P=0.002).