Abstract
Purpose: To investigate high magnitude with-the-rule astigmatism (WTRA, plus cylinder with axis between 75 and 105 degrees) as a risk factor for myopic progression in children.
Methods: Retrospective case-control study. Medical records were screened using CPT codes and age of visit. Subjects were included if the age at initial and final refractive visits were < 8 years and > 10 years, respectively, and had at least five years of follow up. Exclusion criteria include a history of intraocular/oculoplastic pathologies, surgeries, lasers, presence of pathologic myopia (magnitude > 8 diopters). Eyes were categorized based on the initial refraction: no astigmatism (NA), non-WTRA (cylinder outside of 75-105 degree range), low-WTRA (cylinder < 2 D) or high-WTRA (cylinder > 2 D).
Results: A total of 2974 records were screened. 202 eyes of 110 patients were included; 79 (39%) were NA, 81 (40%) were low-WTRA, 24 (12%) eyes were high-WTRA, and 18 (9%) were non-WTRA. High-WTRA had the least hyperopic initial spherical equivalence (0.5 +/- 6.4 D) compared to NA (2.2 +/- 3.0 D), non-WTRA (2.3 +/- 3.2 D), and low-WTRA (3.2 +/- 2.7 D, P = 0.009). When comparing the rates of myopic refractive change per year, patients with high-WTRA demonstrated a significantly greater rate (-0.24 +/- 0.21 D/year) than those without high-WTRA (-0.13 +/- 0.22 D/year, P = 0.0041).
Conclusions: Compared to cohorts with NA, non-WTRA or low-WTRA, children with high-WTRA show a significantly higher rate of myopic progression when followed for five or more years.