Participants
Employees from two office furniture manufacturing
companies in west Michigan were invited to participate in this
study. Inclusion in the study required that participants occupy
a dedicated workspace in a corporate facility, use a computer
for a minimum of four hours per day (self-reported) and were
currently not receiving medicaltreatment for eye or body
discomfort that might affect computer display configuration in
his or her workspace. Additionally, volunteers had to fit into
one of the two groups; younger than 39 years of age, or older
than 45 with evidence of presbyopia and use of multifocal
lenses while viewing the computer display. Individuals with
multifocal contact lenses were allowed to participate as long
as both lenses corrected for far and close vision deficits.
Based on the selection criteria 47 participants were chosen,
29 males and 18 females. The prepresbyope group included
24 people who ranged in age from 25 to 38 (mean 31.2yrs).
The multifocal group contained 23 people who ranged in age
from 45 to 68 (mean 54.3yrs). Anthropometric body
dimensions were measured after participants agreed to take
part in the study. Based on sitting eye height (buttock to eye;
item 14, CAESAR data base, 2002) females represented the
5
th
percentile through the 98
th
percentile, and males
represented the 10
th
percentile through the 99
th
percentile.
Mean sitting eye height for the prepresbyope group was 30.8”
(27.5” to 35.25”) and 31.2” for the multifocal group (27.5” to
34.5”). The tallest prepresbyope male was 99
th
percentile
compared to 97
th
percentile for the multifocal male.