Stereoacuity of preschool children with and without vision disorders.
OBJECTIVE
To evaluate associations between stereoacuity and presence, type, and severity of vision disorders in Head Start preschool children and determine testability and levels of stereoacuity by age in children without vision disorders.


METHODS
Stereoacuity of children aged 3 to 5 years (n = 2898) participating in the Vision in Preschoolers (VIP) Study was evaluated using the Stereo Smile II test during a comprehensive vision examination. This test uses a two-alternative forced-choice paradigm with four stereoacuity levels (480 to 60 seconds of arc). Children were classified by the presence (n = 871) or absence (n = 2027) of VIP Study-targeted vision disorders (amblyopia, strabismus, significant refractive error, or unexplained reduced visual acuity), including type and severity. Median stereoacuity between groups and among severity levels of vision disorders was compared using Wilcoxon rank sum and Kruskal-Wallis tests. Testability and stereoacuity levels were determined for children without VIP Study-targeted disorders overall and by age.


RESULTS
Children with VIP Study-targeted vision disorders had significantly worse median stereoacuity than that of children without vision disorders (120 vs. 60 seconds of arc, p < 0.001). Children with the most severe vision disorders had worse stereoacuity than that of children with milder disorders (median 480 vs. 120 seconds of arc, p < 0.001). Among children without vision disorders, testability was 99.6% overall, increasing with age to 100% for 5-year-olds (p = 0.002). Most of the children without vision disorders (88%) had stereoacuity at the two best disparities (60 or 120 seconds of arc); the percentage increasing with age (82% for 3-, 89% for 4-, and 92% for 5-year-olds; p < 0.001).


CONCLUSIONS
The presence of any VIP Study-targeted vision disorder was associated with significantly worse stereoacuity in preschool children. Severe vision disorders were more likely associated with poorer stereopsis than milder or no vision disorders. Testability was excellent at all ages. These results support the validity of the Stereo Smile II for assessing random-dot stereoacuity in preschool children.
*OD, FAAO †PhD ‡OD, MS, FAAO §MD, MSCE ∥PhD, OD, FAAO **MS The Pennsylvania College of Optometry at Salus University, Philadelphia, Pennsylvania (EBC); Scheie Eye Institute, Department of Ophthalmology, University of Pennsylvania, Philadelphia, Pennsylvania (GSY, MGM, JH); College of Optometry, The Ohio State University, Columbus, Ohio (MTK); The Children's Hospital of Philadelphia, University of Pennsylvania, Philadelphia, Pennsylvania (GEQ); School of Optometry, University of California, Berkeley, Berkeley, California (DOB); Northeastern State University, Tahlequah, Oklahoma (LAC); and the New England College of Optometry, Boston, Massachusetts (BM).
Elise B
EB
Ciner
Gui-Shuang
GS
Ying
Marjean Taylor
MT
Kulp
Maureen G
MG
Maguire
Graham E
GE
Quinn
Deborah
D
Orel-Bixler
Lynn A
LA
Cyert
Bruce
B
Moore
Jiayan
J
Huang
D000550:Amblyopia / Q000503:physiopathology; D002675:Child, Preschool; D002755:Choice Behavior; D003867:Depth Perception / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D012030:Refractive Errors / Q000503:physiopathology; D013285:Strabismus / Q000503:physiopathology; D014786:Vision Disorders / Q000503:physiopathology*; D015351:Vision Screening / Q000379:methods; D014792:Visual Acuity / Q000502:physiology*