Medscape reported on Friday that thinning of the retina has been observed at A1c levels below the threshold used to define prediabetes. The finding points to structural changes in the eye at blood sugar readings that would not currently trigger a prediabetes diagnosis, according to the outlet.
The report, published October 2, 2026, centers on the retina — the light-sensitive tissue at the back of the eye. Medscape's headline frames the key detail as the A1c level at which the thinning appears: beneath the cutoff clinicians use to identify prediabetes.
That framing matters because A1c thresholds serve as the standard dividing line for flagging elevated blood sugar before type 2 diabetes develops. If retinal changes can be detected earlier than that line, it raises the question of whether the current cutoff captures everyone at risk. Medscape's report does not, in the material available, specify the study population, the exact A1c value involved, or the magnitude of the thinning observed.
The summary provided offers no further detail on the study design, the number of participants, or whether the findings have been peer-reviewed or presented at a conference. Those specifics would be needed to judge how broadly the results apply.
What to watch next: whether the researchers publish the full data — including the precise A1c level and the size of the effect — and whether professional groups revisit screening guidance for retinal imaging in people whose blood sugar sits below today's prediabetes threshold.
