The current Oxymap T1 is composed of two digital cameras, a custom optical adapter, 1600×1200 square pixels (Insight IN1800 Diagnostic Instruments Inc., Sterling Heights, MI) and an image splitter as an addition to a fundus camera (Topcon TRC-50DX Topcon Corp., Tokyo, Japan).

The Oxymap T1 has been used in many studies to increase knowledge of oxygen metabolism in various retinal diseases such as diabetic retinopathy, 3 age-related macular degeneration, 4 central retinal vein occlusion, 5 retinitis pigmentosa, 6 and glaucoma. One wavelength is sensitive to the changes in oxygen saturation of the retinal vessels, while the second wavelength (isosbestic) is not. Both are conventional fundus camera–based systems and acquire two fundus images simultaneously with two wavelengths of light. Currently, two retinal oximeters are commercially available, the Imedos oximeter (Imedos Systems UG, Jena, Germany) and the Oxymap T1 (Oxymap ehf., Reykjavik, Iceland). 2 Retinal oximeters measure the relative oxygen saturation in the retinal vessels by using the difference of light absorbance of oxyhemoglobin and deoxyhemoglobin. The development of this retinal oximetry technique has been extensively described by Beach. 1 were the first to develop a technique for the measurement of relative oxygen saturation of the retinal vessels. Here we tested such an oximeter and show that its performance compares well with that of the gold standard Oxymap T1 in healthy adults. To date, to our knowledge, no oximeters are available for handheld use and for measurement in supine position in infants and bedridden adults. Performance of the prototype, mobile handheld oximeter Corimap camera compares well with the Oxymap T1, with a slightly larger standard deviation in oxygen saturation measurements, both in upright and supine patients. In supine position, measured with the handheld oximeter, the oxygen saturation in the arterioles was 92.3% ± 5.8% and 59.2% ± 6.1% in the venules. The oxygen saturation was higher in the arterioles than the venules for both cameras ( P < 0.05). 57.7% ± 6.4% for the handheld camera and Oxymap T1, respectively. In upright position, the oxygen saturation for the arterioles was 92.2% to 4.9% vs. Twenty-one subjects (age 25 ± 2 years) were included. Retinal oxygen saturation values were determined for both the handheld camera and the Oxymap T1. Both cameras are dual-wavelength oximeters and acquire images with wavelengths of 570 and 600 nm. Retinal images were acquired with the handheld oximeter and the Oxymap T1. Healthy volunteers (age 18–35) were recruited at the Leiden University Medical Center. A handheld oximeter is needed for measurements of infants with retinopathy of prematurity as well as acutely injured and bedridden adults.

The objective of this study was to measure the relative retinal oxygen saturation with a prototype, mobile handheld oximeter in upright and supine position and to compare these measurements to the gold standard Oxymap T1 retinal oximeter in upright position.

Diggz xenon adults only password 2018