Abstract
Purpose :
To examine the longitudinal behavior of refractive errors in premature children during the first three years of life.
Methods :
This prospective cohort study included 100 premature children who were offered cycloplegic refraction every six months until three years of life. Cycloplegic refractions were converted into power vector components: M (spherical equivalent), J0 [positive for with-the-rule (WTR) and negative for against-the-rule (ATR) astigmatism], and J45 (oblique astigmatism). Each power vector component was fitted by linear regression to determine the mean change in refractive errors over three years. The longitudinal behavior of the eyes outside the AAO and AAPOS consensus guidelines was analyzed to determine if there is an ideal time for ophthalmologic screening.
Results :
The mean J0 was 0.59 (95% CI 0.53 to 0.66) at 6 months, which decreased to 0.29 (95% CI 0.19 to 0.39) at 18 months and changed minimally thereafter (< 0.1). The mean change in J0 was -0.32 (95% CI -0.40 to -0.23, p < 0.001) at 36 months compared to baseline (equivalent to 0.64 diopters). The mean difference in J0 from baseline was greatest before 18 months: J0 changed from baseline by 0.10 between 12 and 18 months while the change in J0 from baseline between months thereafter was < 0.01. Twenty-six percent of eyes were outside the WTR astigmatism consensus guidelines. For J0, 100% of eyes outside the consensus guidelines at 18 months or greater remained outside the consensus guidelines at 36 months. When analyzed in 1-year increments, the mean change in both J0 and M was lowest at 24 months. 11% of patients remained outside the refractive consensus guidelines after 24 months. M decreased by 1.13 (95% CI 0.92 to 1.35, p < 0.001) over the 3-year study period (equivalent to 1.13 diopters). For M, 18% of eyes were outside the consensus guidelines. No eyes were outside the ATR astigmatism or oblique astigmatism consensus guidelines.
Conclusions :
WTR astigmatism and spherical equivalent decreased over the first three years of life, which was both statistically and clinically significant. WTR astigmatism accounted for the majority of these amblyopogenic refractive errors. Given that the change in J0 leveled off after 18 months and the lowest rate of change was seen at 24 months in both J0 and M, it may be appropriate to screen this high-risk population around 18 to 24 months, particularly for WTR astigmatism.
This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.