The optical coherence tomography (OCT) is a precision instrument that uses a measuring procedure that is very similar to ultrasound. In stead of ultrasound it uses low energy laser light. The transsections of the retina delivered by the OCT produce very realistic pictures of the structure of the tissue. This device facilitates the diagnostics en therapy of a glaucoma or other retinal pathology. Using the OCT one can clarify if diabetic retinopathy or a venous occlusion is responsible for a pronounced thickenening of the retina in the macular region. With the OCT the diagnostics of glaucoma and the inhibition of its progression can be improved