A clinical test of dynamic visual acuity for children.
OBJECTIVE
Children with sensorineural hearing impairment (SNHI) and concomitant vestibular hypofunction demonstrate deficits in gaze stability that may affect reading. The objective of this study was to develop a reliable, valid clinical test of dynamic visual acuity (DVA) for children.


METHODS
Seventy-six typically developing children, 26 adults and 11 children with sensorineural hearing impairment participated. Visual acuity was tested under three conditions: (1) head stable (static acuity), (2) head tipped forward 30 degrees and passively rotated 30 degrees in the yaw plane at 2 Hz (horizontal dynamic acuity) and (3) head passively moved in the pitch plane 30 degrees at 2 Hz (vertical dynamic acuity, vDVA). The difference, in number of chart lines, between static dynamic acuity was calculated (dynamic acuity score). Based on normative data collected, results were scored as: (1) pass < or =2S.D. from the normative mean and (2) fail > or =2S.D. from normative mean. Children were grouped by age to enable examination of the effect of age on scores.


RESULTS
We found excellent test-retest and inter-tester reliability (ICC(2,2)=0.94 and ICC(3,2)=0.84) for the horizontal dynamic acuity (hDVA) test. Sensitivity, specificity, positive and negative predictive values were 100% to identify children with bilateral vestibular hypofunction (BVH). Although a statistical difference was found, the difference was not clinically significant (all achieved DVA scores <2 lines). The vertical dynamic acuity test was not tolerated by most children, precluding its usefulness.


CONCLUSIONS
The clinical test of horizontal dynamic acuity is a reliable test for children as young as 3 years. It is simple and inexpensive, and will enable identification of those for whom more extensive testing is warranted.
Rine
Rose Marie
RM
Department of Orthopaedics and Rehabilitation, Division of Physical Therapy, University of Miami School of Medicine, Coral Gables, FL 33146, USA. rmrine@miami.edu
Braswell
Jennifer
J
D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D006319:Hearing Loss, Sensorineural / Q000503:physiopathology*; D006801:Humans; D012027:Reflex, Vestibulo-Ocular / Q000502:physiology*; D012680:Sensitivity and Specificity; D014792:Visual Acuity