The diameter of the human retinal branch vessels does not change in darkness

In the main part of our study we examined the changes of the retinal branch vessel diameters during dark and light adaptation. We used a "hybrid" technique, using the newly developed Retinal Vessel Analyzer (RVA) to analyze recordings of images made with a scanning laser ophthalmoscope (SLO) employing near-infrared illumination. Since there have been no previous reports of using SLO data with the RVA software in a clinical context, additional tests were performed to assess the reproducibility and the sensitivity of this combined method. The significance of the results given here is further discussed in the main paper.