Oxymap for better glaucoma diagnosis
Glaucoma, a condition that causes damage to your eye’s optic nerve and gets worse over time has been one of the major causes of irreversible blindness. It is often associated with a buildup of pressure inside the eye and a slowly progressive disease and the most worrying factor is that it may not show up until later in life. A growing body of evidence suggests that disturbances in retinal blood flow and oxygenation are related to several retinopathies and glaucoma, which can severely impair vision. As technology has made lot of strides in glaucoma detection and management, the oxymap is one among the newest technology for better glaucoma diagnosis.
Retinal oximetry is a non-invasive imaging technique that allows for the calculation of the relative oxygen saturation of retinal blood vessels. The basic retinal oximeter consists of a fundus camera with an attached image splitter. The image splitter contains mirrors that split the beam from the camera into smaller beams based on wavelengths of light, as well as filters that further filter the beam. The apparatus also includes a digital camera to record the fundus images. Computer software detects retinal vessels and uses relative light intensities to calculate relative vessel oxygenation.
The Oxymap simultaneously acquires digital images at two wavelengths and automatically tracks retinal vessels on both images. Retinal vessel oxygen saturation is estimated by spectrophotometric analysis of light reflected from retinal vessels and from the immediately surrounding retina. Oxygen saturation measurements are made on major temporal arteries and veins. The first and second degree vessels are used, with the addition of third degree vessels in images where peripapillary haemorrhage prevented analysis close to the optic disc. Vessel segments chosen for analysis are used consistently for consecutive measurements in the same retina.
Speaking to Techspirit about the oxymap and its working, Dr Rajesh S Kumar, Deputy Director of Research, Consultant Glaucoma Services, Narayana Nethralaya, Bengaluru says: “The oxymap which is the latest technology looks at oxygen saturation of the blood vessels both artery and veins in the eye and around optic nerve. It is done completely by imaging, there is no need to put up pulse oxymeter or the blood level. It is non contact and is run on pure photography technology.”
It is to be noted that oxymap as of now has shown that the oxygen saturation is affected to a large extent in patients with glaucoma and other retinal disorders. Meanwhile, the oxymap might also be an interesting tool in the future as it may even be able to pick up diseases like diabetes or hypertension without having to do a single blood test. Narayana Nethralaya in Bengaluru is one among the few centers in India to have this oxymap equipment, further added Dr Rajesh.