A Healthy Human Eye (image) Johns Hopkins Medicine Caption This is a diagram of a healthy human eye. The macula is marked at the back of the eye with a black oval. Credit National Eye Institute, National Institutes of Health Usage Restrictions None 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.