The amblyopia treatment study visual acuity testing protocol.
OBJECTIVE
To evaluate the reliability of a new visual acuity testing protocol for children using isolated surrounded HOTV optotypes.


METHODS
After initial pilot testing and modification, the protocol was evaluated using the Baylor-Video Acuity Tester (BVAT) to present isolated surrounded HOTV optotypes. At 6 sites, the protocol was evaluated for testability in 178 children aged 2 to 7 years and for reliability in a subset of 88 children. Twenty-eight percent of the 178 children were classified as having amblyopia.


RESULTS
Using the modified protocol, testability ranged from 24% in 2-year-olds to 96% in 5- to 7-year-olds. Test-retest reliability was high (r = 0.82), with 93% of retest scores within 0.1 logMAR unit of the initial test score. The 95% confidence interval for an acuity score was calculated to be the score +/-0.125 logMAR unit. For a change between 2 acuity scores, the 95% confidence interval was the difference +/-0.18 logMAR unit.


CONCLUSIONS
The visual acuity protocol had a high level of testability in 3- to 7-year-olds and excellent test-retest reliability. The protocol has been incorporated into the multicenter Amblyopia Treatment Study and has wide potential application for standardizing visual acuity testing in children.
Holmes
J M
JM
Mayo Clinic, Ophthalmology West 7, Rochester, MN 55905, USA. holmes.jonathan@mayo.edu
Beck
R W
RW
Repka
M X
MX
Leske
D A
DA
Kraker
R T
RT
Blair
R C
RC
Moke
P S
PS
Birch
E E
EE
Saunders
R A
RA
Hertle
R W
RW
Quinn
G E
GE
Simons
K A
KA
Miller
J M
JM
D000550:Amblyopia / Q000503:physiopathology / Q000628:therapy*; D001285:Atropine / Q000627:therapeutic use; D002648:Child; D002675:Child, Preschool; D006801:Humans; D009184:Mydriatics / Q000627:therapeutic use; D015203:Reproducibility of Results; D012683:Sensory Deprivation; D014787:Vision Tests / Q000379:methods*; D014792:Visual Acuity / Q000502:physiology*
D009184:Mydriatics; D001285:Atropine