Exposure to drug misuse in utero associated with long-term visual morbidity

This large retrospective cohort study found that exposure to maternal drug misuse in utero is associated with a significantly higher prevalence of strabismus and nystagmus in the long term, with abnormalities tending to persist at five years of age.

The authors write that this study, which was conducted in the United Kingdom, helps provide solid evidence on the causal relationship between substance misuse in pregnancy and visual morbidities.

They examined the prevalence of short- and long-term (five-year) visual morbidities in 301 children born between 2000 and 2004 to mothers misusing substances during pregnancy and compared this with a control group of 7,887 age-matched children.

Ophthalmology referrals, strabismus and nystagmus were significantly more common in the study group compared with the control group. In the study group, at baseline referral, 15.3 percent had strabismus compared to 2.8 percent in control group, and 3.7 percent had nystagmus compared to 0.004 percent in the control group.

At the 5-year follow-up, the prevalence of strabismus and nystagmus in the study group was 14 percent and 3.3 percent, respectively. A total of 42.4 percent of these children at age 5 had no demonstrable binocular vision and 28.2 percent had visual acuity of 0.3 logMAR or worse in one or both eyes.

The authors note that attendance at the last follow-up was poor (61.9 percent). This study therefore highlights the need for structured ophthalmologic surveillance of this population and supported attendance, as nonattendance is more likely in this group of children. (consider deleting from “and supported attendance” until the end of the sentence.)

They say that the results will help encourage the establishment of local protocols for early referral, assessment and management of this high-risk population. Training to conduct visual screening could also be potentially extended to staff at perinatal substance misuse clinics.