Cardiometabolic Disorders Tend to Accompany a ‘Lazy Eye’

Somehow, people with persistent amblyopia (also known as “lazy eye”) from childhood had a higher risk of cardiometabolic disorders in adulthood, an observational cohort study showed.

Within the U.K. Biobank, people over 40 years of age living with this vision deficit were more likely to have the following conditions compared with peers without amblyopia:

• Obesity (adjusted OR 1.16, 95% CI 1.05-1.28)
• Hypertension (adjusted OR 1.25, 95% CI 1.13-1.38)
• Diabetes (adjusted OR 1.29, 95% CI 1.04-1.59)

Amblyopia was also associated with an increased risk of myocardial infarction (adjusted HR 1.38, 95% CI 1.11-1.72) and death (adjusted HR 1.36, 95% CI 1.15-1.60) over a window of over 11 years, reported Jugnoo Rahi, MBBS, PhD, MSc, ophthalmic epidemiologist of University College London’s (UCL) Great Ormond Street Institute of Child Health, and colleagues in eClinicalMedicine.

The investigators emphasized that they could not prove causation in the study or pinpoint a potential mechanism behind their findings — for example, they could find no differences in smoking status or alcohol consumption between those with amblyopia and those without.

“In the meantime, healthcare professionals should be cognizant that a diagnosis of amblyopia in a child is associated with increased cardiometabolic morbidity in later life,” they concluded.

“Our research means that the ‘average’ adult who had amblyopia as a child is more likely to develop these disorders than the ‘average’ adult who did not have amblyopia. The findings don’t mean that every child with amblyopia will inevitably develop cardiometabolic disorders in adult life,” cautioned study lead author Siegfried Wagner, BM BCh, PhD, MSc, of UCL and Moorfields Eye Hospital, in a press release.

Amblyopia is a common neurodevelopmental condition that affects 1-3% of children and causes reduced vision in one eye only. Childhood screening programs have led to timely ophthalmic intervention for many — virtual reality therapy, for example, becoming available more recently — though some people continue to have persistent visual impairment as adults.

Pediatrician Stephen Daniels, MD, PhD, of University of Colorado School of Medicine and Children’s Hospital Colorado, said that an amblyopia-cardiometabolic link would be “hard to explain from a mechanism standpoint.” He suggested that a “third factor (perhaps the intrauterine environment) influences both outcomes (amblyopia and cardiometabolic dysfunction), but this would be very speculative,” he told MedPage Today in an email.

Rahi and colleagues cited some possible common maternal and perinatal factors for these two outcomes.

“Amblyopia has also been directly and indirectly, through ocular risk factors of strabismus and refractive error, linked with adverse parent-origin factors, including increased maternal age, maternal smoking, alcohol consumption, and lower socioeconomic status. There are consistent associations between these perinatal risk factors and cardiometabolic disease in adulthood,” they wrote.

Future research may be needed to replicate the association, and from there, more work to understand what might underlie it, Daniels said.

The cross-sectional, longitudinal analysis was based on U.K. Biobank volunteers who had been recruited from 2006 to 2010. Included were 126,399 people who underwent ocular examinations and were asked if they had been treated for amblyopia in childhood and if they still had the condition in adulthood.

Of the 3,238 answering yes to childhood amblyopia, 2,647 said they still had persistent reduced vision in one eye.

On retinal imaging of 67,321 people, amblyopic eyes had significantly increased venular caliber, increased tortuosity, but lower fractal dimension and thinner ganglion cell-inner plexiform layer (mGC-IPL). Unaffected fellow eyes of people with amblyopia also had significantly lower retinal fractal dimension and thinner mGC-IPL. Amblyopic eyes with a persisting visual deficit had smaller optic nerve disc height and width.

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