A Comparison between a prototype, mobile, handheld retinal oximeter and the current "gold standard" the Oxymap T1

This study protocol has as a main goal to make retinal oximetry available for children with vascular retinal diseases. Retinal oximetry is an imaging technique, which utilizes the difference in light absorption of hemoglobin bound and unbound to oxygen at different wavelengths of light, to determine the relative oxygen saturation of the blood in the retinal vessels.



The primary objective of this study is to determine the Optical Density Ratio (ODR) for the prototype CORIMAP camera and compare the ODR values with the Oxymap T1 mounted on a regular fundus camera in a healthy adult population. For comparison, it is paramount to determine the ODR of both oximeter cameras in normoxia and hyperoxia conditions. With this study protocol, we wish to introduce a prototype handheld camera with oximetry abilities, called the CORIMAP camera. This study aims to validate and calibrate the CORIMAP camera in a healthy adult population.



The study design is a prospective intervention study of healthy volunteers. In these healthy volunteers the ODR will be determined with a prototype mobile handheld oximeter and the current Oxymap T1 oximeter in two different positions as well as different breathing circumstances (normoxia and hyperoxia).



Recruitment will be at the Leiden University Medical Centre. The study population consists of healthy volunteers in the age range of 18 - 35 years of age.



The pupil of one of the eyes of the participants will be dilated with 1 drop Tropicamide 0.5% during the ophthalmological examination. In one of the three phases of the photo session, participants will be supplied with 100% oxygen, isocapnic until hyperoxia is reached. This procedure will be repeated for both oximeter cameras. An arterial line will be inserted in the last fase of the study procedure to monitor the blood gas values during



With this study protocol, we wish to introduce a prototype handheld camera with oximetry abilities, called the CORIMAP camera. Before making the transition to an infant/child population, this study aims to validate and calibrate the CORIMAP camera in comparison to the current Oxymap T1 in a healthy adult population.

This study protocol has as a main goal to make retinal oximetry available for children with vascular retinal diseases. Retinal oximetry is an imaging technique, which utilizes the difference in light absorption of hemoglobin bound and unbound to oxygen at different wavelengths of light, to determine the relative oxygen saturation of the blood in the retinal vessels. The Compact Retinal Mapper (CORIMAP) camera has been developed to make retinal oximetry available for the use
in infants, in order to gain knowledge about the oxygen metabolism of the retina in premature born children with a risk of developing ROP.

The volunteers participating in this study will visit the outpatient clinic of the department of ophthalmology, the LUMC
once for this study.

The purpose of a retinal oximeter is the measure the relative oxygen saturation in the retinal vessels. Therefore,
measuring oxygen saturation in different oxygen conditions (normoxia / hyperoxia) is paramount determining the
sensitivity of the measurements of the CORIMAP camera.

In one of the three phases of the photo session, participants will be supplied with 100% oxygen, isocapnic until
hyperoxia is reached. This procedure will be repeated for both oximeter cameras. During this stage, an arterial line wil
be inserted in the participants for monitoring the bloodgas values. During the recovery phase, retinal images will be
captured every 15s during a period of 3 min. The pupil of one of the eyes of the participants will be dilated with 1 drop
Tropicamide 0.5% during the ophthalmological examination for the duration of the study procedure