Abstract
Purpose: :
To test a new non-invasive tool to measure absolute hemoglobin concentration in retinal arteries.
Methods: :
50 healthy volunteers as well as 40 anemic, otherwise healthy pregnant patients from the Triemli Hospital, Zürich, were included. Hemoglobin concentration was quantified by a blood draw of a cubital vein using Advia®2120 hematology system. Using a non-mydriatic digital Fundus Camera (Niked AFC-230) pictures of the central fundus were taken from each study patient. Segments of retinal arteries were selected by the investigator. The intensitiy of the green channel - according to the absorption maxiumum of hemoglobin - of the camera chip was determined with the aid of the law of Lambert Beer. Absolute hemoglobine concentration was calculated in relation to the vessel volume.
Results: :
83 females and 7 males were included. Mean age was 32 (range 18-63). Hemoglobin levels taken from the cubital veins ranged from 8.1-11.9 g/dL (mean 10.0), hemoglobin levels below 11.4 g/dL calculated from the non-invasive technique corresponded to the venous value with r = 0.91
Conclusions: :
This new technique is suitable for monitoring hemoglobin concentrations in a non-invasive way and allows us for measuring hamoglobin on the site of the retinal pathology and therefore may give us further information about hemodynamic alterations in retinal diseases and may provide a new possibility in finding therapy options.
Keywords: retina • imaging/image analysis: clinical