The diameters of the human retinal branch vessels do not change in darkness

György Barcsay, András Seres, János Németh

Research output: Contribution to journalArticle

12 Citations (Scopus)


PURPOSE. To examine whether the diameters of retinal branch vessels of the human eye change during dark and light adaptation. METHODS. Images (S-VHS recordings) were obtained of the peripapillary region in 11 eyes of 11 healthy young adults (seven women, four men; mean age, 26.4 years). The images were made under a sequence of different illumination conditions (light, 30 minutes of darkness, light) with a scanning laser ophthalmoscope (SLO), using near-infrared illumination (785 nm). The recordings were then analyzed with a retinal vessel analyzer (RVA), and the caliber changes of one branch artery and one vein were measured in each eye. RESULTS. For arteries, the changes of diameter under different illumination conditions showed no clear trend, and comparisons between the different time sections revealed no statistically significant changes (P = 0.933; repeated measures ANOVA). There was a slight dilation (average, 0.9%; range, - 3.9% to + 5.1%) in darkness, and a return to baseline (range, -2.9% to + 2.9%) on restoring normal illumination. Veins during darkness showed a small but fairly consistent constriction (average, 1.5%; range -5.4% to +3.9%; significant P = 0.05), again returning to baseline (range, -2.1% to + 2.6%) in normal light. CONCLUSIONS. The small changes of retinal branch vessel diameters under different light conditions probably have little influence on the possible changes of retinal blood flow in healthy subjects.

Original languageEnglish
Pages (from-to)3115-3118
Number of pages4
JournalInvestigative Ophthalmology and Visual Science
Issue number7
Publication statusPublished - Jul 1 2003

ASJC Scopus subject areas

  • Ophthalmology
  • Sensory Systems
  • Cellular and Molecular Neuroscience

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