A recent study evaluated the effects of prediabetes and diabetes on macular thickness and retinal vascular calibers and found that early changes to the retina had significant effects. The population-based study conducted in Northern Finland included 2,005 individuals divided into three groups: those with diabetes (n=57), those with prediabetes (n=1,638) and those with normal glucose metabolism (n=310).

The researchers measured the total thickness of the macula as well as central retinal arteriolar and vascular equivalents. They noticed significant macular thinning—especially in the pericentral area—among the prediabetes group. Macular cube average thickness and volume also decreased significantly as glucose metabolism worsened.

The researchers found that central retinal arteriolar equivalent decreased significantly with increasing diabetes measures.

In conclusion, the researchers found significant macular thinning in prediabetes and decreased retinal artery diameters as a result of impaired glucose metabolism. They feel their study provides a new perspective because it “revealed that the early and subtle changes caused by prediabetes as macular thinning had significant average causal mediation effect on retinal vessels” and supported the neurodegenerative theory of diabetes-induced changes in the retina.

Huru JM, Leiviska L, Saarela V, et al. Prediabetes influences the structure of the macula: Thinning of the macula in the Northern Finland Birth Cohort. Br J Ophthalmol. October 7, 2020. [Epub ahead of print].