A study based in Finland found a significant relationship between retinal vessel diameter measures and parameters related to both macular and optic nerve head (ONH) characteristics. An increase in retinal vessel diameters was associated with increased macular thickness, macular volume, ganglion cell-inner plexiform layer (GC-IPL) thickness, retinal nerve fiber layer (RNFL) thickness and optic nerve rim area. The researchers believe that understanding the normal anatomy and relationships between retinal vessel diameter with both retinal and optic nerve parameters will be useful when detecting suspected diseases.

The study analyzed retinal vessel diameter measures and posterior segment OCT data from a cohort of 2,155 middle-aged Caucasians. It noted an association between larger retinal vessel diameter and a thicker macula and increased macular volume. An increase of one measure of standard deviation in average macular thickness and volume was associated with a 3.28µm and a 3.19µm increase in arteriolar diameter as well as a 5.10µm and a 5.08µm increase in venular diameter, respectively.

The researchers also found that an increase of one measure of standard deviation in rim area, GC-IPL thickness and RNFL thickness was associated with a 1.21µm, 2.68µm and 3.29µm increase in arteriolar diameter and a 2.13µm, 4.02µm and 5.04µm increase in venular diameter, respectively. No significant association was found between retinal vessel diameter and cup-to-disc ratio as well as the multivariate-adjusted disc area.

The researchers highlighted that increased GC- IPL thickness in all sectors was associated with increased retinal vessel diameter measures, which can help to clarify the possible vascular causes of glaucoma. They believe that these anatomical relationships with other retinal structures can help in identifying initial changes and possibly even initiating preventive measures against developing diseases.