The front of the eye may look like a clear window and although it is just half a millimetre thick it has in fact many layers which are impossible to see with the naked eye. The slit lamp is a high powered microscope with a very intense light source that provides a very detailed examination of these layers. Since there are many conditions which result in a “red eye”, only by detailed examination with this equipment can an accurate diagnosis be made. We use the slit lamp on every patient we see.