This is the next article in our ‘Light and health’ series, where we look at how light affects our physical and mental health in sometimes surprising ways. Read other articles in the series . You’re not feeling well.
You’ve had a pounding headache all week, dizzy spells and have vomited up your past few meals. You visit your GP to get some answers and sit while they shine a light in your eyes, order a blood test and request some medical imaging. Everything your GP just did relies on light.
These are just some of the optical technologies that have had an enormous impact in how we diagnose disease. 1. On-the-spot tests Point-of-care diagnostics allow doctors to test patients on the spot and get answers in minutes, rather than sending samples to a lab for analysis.
The “flashlight” your GP uses to view the inside of your eye (known as an ophthalmoscope ) is a great example. This allows doctors to detect abnormal blood flow in the eye, deformations of the cornea (the outermost clear layer of the eye), or swollen optical discs (a round section at the back of the eye where the nerve link to the brain begins). Swollen discs are a sign of elevated pressure inside your head (or in the worst case, a brain tumour) that could be causing your headaches .
The invention of lasers and LEDs has enabled many other miniaturised technologies to be provided at the bedside or clinic rather than in the lab. Pulse oximetry is a famous example, where a clip attached to your finger reports .