Research conducted in Australia recently determined that specific aspects of intrauterine skeletal growth correlate with both a higher risk of myopia and more alterations in ocular biometry. The researchers believe the effects of these changes may persist into adulthood. Of note, they highlighted that the prevalence of myopia was highest among participants with consistently short or long femur lengths. The researchers speculate that this could indicate the relationship between the two is not appreciably modified by processes affecting refractive error that take place in response to environmental stimuli present during school-age years.

The analysis investigated possible associations between fetal growth trajectories and myopia, axial length and corneal radius of curvature measured in a cohort of 498 Caucasian adults aged around 20 years. The researchers collected fetal biometric measurements via ultrasound scans performed at 18, 24, 28, 34 and 38 weeks of gestation. They then recorded refractive error measurements at the 20-year follow-up.

The most notable finding was the existence of trends that suggested a close and significant association between myopia and intrauterine skeletal development, particularly as reflected by femur length growth trajectory. There was also a trend toward increased prevalence with larger fetal head circumference in late gestation, although it was not statistically significant.

“Fetal head circumference development may play a small role in the development of refractive error,” the researchers wrote. “If so, this trend could be interpreted in terms of the effect of this growth on ocular biometry.”

The study also found that trajectory groups reflecting faster head circumference, femur length or estimated fetal weight growth correlated with significantly flatter corneas and a general, but not statistically significant, increase in axial length.

More detailed investigation is required to elaborate on the specific pathophysiology underlying the observed trends and quantify the relative extent to which different risk factors contribute to refractive error in young adults, the researchers noted. They added, however, that their findings may lead to methods that help identify infants at risk of developing myopia as early as 38 weeks of gestation and implement preventative strategies.

Dyer KIC, Sanfilippo PG, White SW, et al. Associations between fetal growth trajectories and the development of myopia by 20 years of age. Invest Ophthalmol Vis Sci. 2020;61(14):26.