Patients with retinal conditions may need diagnostic tests administered by their eye surgeon to evaluate their retinal disorders. Retinal diagnostic tests are divided into two principal categories. In the first category are tests that are designed to display images from optical devices. In the second category are tests designed to display images generated from retinal scans.
Retinal Photography
In the first category are retinal digital photographs with or without diagnostic dyes. If no diagnostic dye is used we call this test retinal photography.
Abnormal retinal photo
If dye is used we call this test fluorescein angiography. With fluorescein angiography a sterile preparation of fluorescein is administered to a vein in the eye and it is photographed with a blue filter light retinal camera. There are no X Rays involved in this test as it is purely photographic. In this fashion the ophthalmologist can evaluate the characteristics of the retinal blood circulation and determine how it may be affected by retinal diseases. A fluorescein angiogram is a time lapsed test.
Abnormal fluorescein angiogram flow seen after time lapse
Ocular Coherence Tomography Tests
In the second category of tests the retinal can be evaluated with OCT (Ocular Coherence Tomography). The principle of OCT is based on optical scatter of a near infrared light. When the images bound back to the OCT its computers process the information creating electronic pictures of the retina.
It is a very useful tests as it can reveal information underneath the retinal surface. This is where some retinal disorders begin and therefore might be detectable before becoming visible with photographic techniques.
Retinal OCT with fluid under the surface