Incidence and Types of Childhood Hypertropia: A Population-Based Study
Received 1 September 2005; accepted 18 January 2006. published online 26 April 2006.
Objective
To determine the incidence and types of childhood hypertropia in a defined population.
Design
Retrospective population-based cohort.
Participants
All pediatric (<19 years of age) residents of Olmsted County, Minnesota, diagnosed with vertical strabismus from January 1, 1985, through December 31, 1994.
Methods
The medical records of all potential patients identified by the resources of the Rochester Epidemiology Project were reviewed.
Main Outcome Measures
Incidence and types of childhood hypertropia.
Results
Forty-two cases of childhood hypertropia were identified during the 10-year period, yielding an annual age- and gender-adjusted incidence of 12.9 (95% confidence interval, 9.0–16.9) per 100000 patients younger than 19 years of age. This rate corresponds to a prevalence of approximately 0.26%, or 1 in 391, of all children younger than 19 years of age. Nearly three fourths (71.4%) of the children had a IVth cranial nerve palsy, primary inferior oblique overaction, Brown syndrome, or a vertical tropia in the setting of an abnormal central nervous system.
Conclusions
The incidence rates for childhood hypertropia in this population-based study are higher than published reports of prevalence. Fourth cranial nerve palsy and primary dysfunction of the inferior oblique muscle were the most common forms of vertical strabismus in this population.
1Department of Pediatric & Adolescent Medicine, Mayo Clinic and Mayo Foundation, Rochester, Minnesota.
2Department of Ophthalmology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota.
3Division of Biostatistics, Mayo Clinic and Mayo Foundation, Rochester, Minnesota.
4Division of Epidemiology, Mayo Clinic and Mayo Foundation, Rochester, Minnesota.
Correspondence to Brian G. Mohney, MD, Department of Ophthalmology, Mayo Clinic, 200 First Street Southwest, Rochester, MN 55905.
Manuscript no. 2005-834.
Supported in part by an unrestricted grant from Research to Prevent Blindness, Inc., New York, New York.
ABSTRACT