Retina and retinal vessels examination
- Angiography: It involves injection of Fluorescein or Indocyanine ICG(green)into the brachial vein, and photographing the posterior part of the eye, using a fundus camera. This test is done for checkingthe retinal and choroid blood flow.Usually, Fluorescein is usedto evaluate the vasculature of retina, forchoroid ICG is used. Fluorescein angiography is mostly applied for evaluation of diabetic retinopathy, vein occlusions, retinal artery occlusions, andwet macular degeneration. ICG is used to examine macular blood, i.e. in age-related wet macular degeneration.Both types of material have very few side effects and can be used with confidence (safely). Rarely allergic reactions (allergic) may occur in some people.ICG is prohibited for people who are allergic to iodine intake.Fluorescein, in some cases up to 24 hours after injection, may cause jaundice of the skin and eyes and orange urine.
- HRA Angiography: Using this techniqueincreases the accuracy of Fluorescein angiography and ICG, and provides the possibility of filming the angiography.
- OCT (Optic Coherence Tomography): A new technique which uses high-resolution tomographic layers of the retina, and provides valuable information for the ophthalmologists. Thus, it is used for diagnosis and follow-up in many retinal diseases such as macular holes, macular edama, macular degeneration, diabetic retinopathy, and glaucoma. Since a light source is applied in this technique, there is no need to contact the eye and the process can be done within a few seconds.
- ERG (ERG):Retinalpotentials study through techniques such as Flash, Pattern ERG and MF is provided bythe Noor Hospital ERG System facilities. These facilities make it possible to study retina diseases. This test measures the overall response of the retina to a light stimulus by the potential difference between the twoelectrodes. One of them is placed slightly below the lower eyelid on the corneaand is in contact with it and the other electrode which is neutral is placed on the skin around the eyes. Anaesthetic drops are used for the convenience of patients and in some cases, for example, when the patient is a child, general anaesthesia is used. These tests are used for the diagnosis of retinal disorders such as retinitis pimentosa or cone dystrophy.
- Electrooculogram (EOG): EOG is one of the most important telectrophysiological tests. This test is applied to assess the pharmacological effects and pathological changes. It is a routine test usedto evaluate the Retinal Pigment Epithelium and light receptors (rods and cone cells). Normally, cornea is approximately 6 millivolts positive compared to the back of the eye (retina). By attaching skin electrodes on both sides of an eye, the potential can be measured by having the subject fixate his or her eyes horizontally on a bright object that periodically emits light.Any set distance subtending about 30 degrees of visual angle is satisfactory. This action produces a voltage swing between the electrodes on each side of the eye, which is charted on graph paper or stored in the memory of a computer This test is particularly valuable for evaluation of patients suspected of having a disease or disorderin retinal pigment epithelium, such as retinitis pigmentosa.