Abstract
Purpose :
The caffeine is a powerful vasoconstrictor ingredient, which affects the blood flow at the level of capillaries structures of the eye. An earlier study (ARVO 2018) demonstrated that, the consumption of a 200 mg of caffeine induces a significant decrease of the blood volume and blood oxygenation in a specific area of the optic nerve papilla in humans. The purposes of the present study were to highlight the caffeine effect in the blood oxygenation, on numerous optic nerve papilla zones. Also, we were interested to establish a pattern for the blood oxygenation variations under caffeine effect, on the papilla area.
Methods :
Ten university healthy students, non-smokers, aged from 21 to 26 years (23.8±1.7) have participated in this study. The blood volume and blood oxygenation at the level of the optic nerve papilla have been estimated simultaneously in numerous zones (100x100) by using the “On Line and Real Time Optic Nerve Blood Oxygenation Mapping” system (WO2017117668A1). Other systemic parameters that can influence the optic nerve’s blood oxygenation rate have also been monitored during the experimentation: the brachial blood pressure (BPA), the heart rate (HR) and the systemic arterial blood oxygenation (SpO2). In a first sequence, measurements have been performed before ingesting a pill containing 200 mg of caffeine, considered as baseline values for each subject. The second sequence of measurements has followed 30 minutes after the pill ingesting (considering that the caffeine effect is maximal 30 minutes after the pill ingesting). For each subject, two pictures of the optic nerve area have been derived after each sequence of measurements - one picture, representing the optic nerve blood oxygenation mapping, and the second picture, representing the optic nerve blood volume mapping.
Results :
The reference images (no caffeine) show that the optic nerve papilla in each subject is uniformly oxygenated to an average value of 65.2%. The caffeine has diminished the rate of blood oxygenation in each individual with an average value of 7.7%. However, the optic nerve papilla in each individual remains relatively uniform oxygenated, to an average value of 57.8%, after the caffeine effect.
Conclusions :
Our study suggest that the new technic for optic nerve blood oxygenation mapping, in combination with the caffeine effect, can be a useful procedure to detect the atrophic zones of the optic nerve papilla of glaucoma patients.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.