Hypertensive retinopathy is usually considered a consequence of established vascular damage. But new research suggests that subtle ocular microvascular abnormalities may already be detectable in children with systemic hypertension before any clinical signs appear.
In a prospective cross-sectional study published in BMC Ophthalmology, an Istanbul-based team used optical coherence tomography (OCT) and OCT angiography (OCTA) to investigate retinal and choroidal changes in 94 children aged 6–18 years with stage 1 primary hypertension and 60 age- and sex-comparable healthy controls. All hypertensive participants had been followed for at least one year and none were receiving anti-hypertensive treatment at enrollment.
Importantly, the hypertensive children showed no clinically detectable ocular disease. Best-corrected visual acuity was 0.00 logMAR in all participants, and no abnormalities were identified on intraocular pressure measurement or anterior and posterior segment examination.
Conventional OCT and several retinal OCTA parameters were also similar between groups. Foveal thickness, subfoveal choroidal thickness, superficial and deep capillary plexus vessel density, foveal avascular zone area, and optic nerve head vessel density showed no significant differences.
The choriocapillaris told a different story.
The researchers measured the proportion of non-perfused choriocapillaris area (NPCA) across three concentric regions centered on the fovea. In every region, NPCA was significantly greater in hypertensive children than controls: 12.3% versus 8.7% within 0.5 mm, 14.5% versus 10.2% at 0.5–1.5 mm, and 16.8% versus 12.1% at 1.5–3 mm. All differences were statistically significant.
The representative OCTA images shown in the study illustrate how these choriocapillaris regions were assessed, complementing the otherwise largely normal retinal and optic nerve vascular measurements.
Because the hypertensive cohort had a significantly higher body mass index, the investigators performed multivariable analyses adjusting for age, sex, and BMI. Hypertension remained independently associated with increased NPCA in the 0.5–1.5 mm and 1.5–3 mm regions, while BMI itself was not independently associated with NPCA.
The study authors suggest that choriocapillaris non-perfusion may therefore precede the better-recognized structural and retinal vascular changes of hypertensive eye disease. If confirmed, OCTA-derived NPCA could potentially offer a noninvasive marker of early microvascular involvement and help identify children who warrant closer systemic and ophthalmic surveillance.
Several caveats remain. The study was cross-sectional, lacked longitudinal blood-pressure data, and did not include detailed ambulatory blood-pressure parameters. Axial length was not measured, and the automated NPCA algorithm used has not yet been specifically validated in pediatric populations. Residual metabolic confounding also cannot be excluded.
While the authors recommend that larger cohort longitudinal studies should now be performed in order to clarify the temporal relationship between choriocapillaris microvascular alterations and systemic hypertension, the findings suggest that the eye may provide an unusually early window onto hypertensive microvascular injury – before conventional fundus examination has anything to show.
