Diagnosis of amblyopia using the 10-diopter fixation test: a proposed modification for patients with unilateral ptosis.
OBJECTIVE
The 10-diopter (D) fixation test is a useful test for detecting amblyopia in children without a manifest deviation and in whom a reliable visual acuity assessment is difficult. The 10 prism diopter is conventionally placed base down.


METHODS
Seventeen children were studied over a 12-month period to determine the effect of prism orientation on the accuracy of the 10-D fixation test in children with unilateral ptosis.


RESULTS
Anomalous results were obtained in 4 of 17 patients with the prism held base up and base down.


CONCLUSIONS
To prevent an erroneous diagnosis of amblyopia in children with unilateral ptosis, the prism should be held base up when performing the 10-D fixation test.
Whittaker
K W
KW
Southampton Eye Unit, Southampton General Hospital, United Kingdom.
O'Flynn
E
E
Manners
R M
RM
D000550:Amblyopia / Q000150:complications / Q000175:diagnosis*; D001763:Blepharoptosis / Q000151:congenital*; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005403:Fixation, Ocular; D006801:Humans; D007223:Infant; D015203:Reproducibility of Results; D014787:Vision Tests / Q000379:methods*; D014792:Visual Acuity