OCT-A proves useful for the diagnosis and follow-up of children with amblyopia. Photo: Erin Jenewein, OD.

The relationship between retinal blood flow and amblyopia has not yet been made clear. A recent study reported that, when compared with the fellow eye, the blood flow density of the macula and the surrounding retinal capillary network of the amblyopic eye in these patients also decreases. In particular, the investigators found that the macular vessel density of the superficial capillary plexus among children with anisometropic amblyopia was lower vs. healthy children. 

The study included 16 children with anisometropic amblyopia and 19 age-matched healthy controls. Participants had an OCT-A examination, with 3mm × 3mm and 6mm × 6mm scans in the macular region. 

The researchers measured perfusion parameters of the superficial retinal layer, including the macular foveal avascular zone area, perimeter and circularity as well as the vessel length density and perfusion density of the foveal, parafoveal and perifoveal regions.

In patients with anisometropic amblyopia, the study authors observed that the foveal avascular zone area was significantly higher in diseased eyes compared with fellow eyes. Additionally, they found that the vessel length density and perfusion density of the foveal average, as well as the nasal quadrant of the perifoveal region in anisometropic amblyopic eyes, were significantly lower vs. fellow eyes. 

When comparing the two groups, the data revealed that the vessel length density of the parafoveal average, the superior, temporal, inferior and nasal quadrants of the parafoveal region and the nasal quadrant of the perifoveal region were significantly lower in anisometropic amblyopic eyes. Additionally, perfusion density of the parafoveal average, and the inferior quadrant of the parafoveal region were significantly lower in anisometropic amblyopic eyes. 

“While the specific mechanism is still unclear, we believe that there is a decrease in retinal vessel density in amblyopia children, and the vessel density in the fellow eye with normal refraction is also affected to some extent,” the study authors noted. “This study provides a certain clinical basis for the future study of the pathogenesis of amblyopia and the application of OCT-A technology for the diagnosis and follow-up of children with amblyopia.”

Liu C, Zhang Y, Gu X, et al. Optical coherence tomographic angiography in children with anisometropic amblyopia. BMC Ophthalmol. June 20, 2022 [Epub ahead of print].