Blood vessels in the eye (IMAGE) Technical University of Munich (TUM) Caption During an eye examination, the diameter of small blood vessels (left) and the dilation of vessels in response to light pulses (right) can be measured. Both are altered in people with long Covid. Credit Department of Nephrology / TUM Usage Restrictions Free for use in reporting on TUM, with the copyright noted License Original content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.