Retina – Fluorescein Angiography
Fluorescein angiography evaluates the blood flow in the retina and choroid.
Your doctor will need to dilate your pupils. Pupillary dilation will make you light sensitive. As a result, it is recommended that you bring sunglasses. As well as making you light sensitive, your vision may be blurry, therefore, it is a good idea to have someone to drive you home after your appointment.
Some people notice vision appears darker or has a coloured tint. This will last only for a few minutes because it takes time for your kidneys to remove the dye from your body. Your urine will turn dark orange or yellow for up to 24 hours following the test. After the fluorescein dye is injected, your skin may turn yellowish for several hours and you should not expose your skin to extreme sunlight for 48 hours.
Central serious retinopathy, or CSR, is 10 times more common in men between 20 and 50, than in women. Up to 50% of people with CSR in both eyes are found to be taking some form of steroids.
Initially, CSR forms below the retina. An accumulation of clear fluid builds up between the retina and the choroid. Eventually, it penetrates the retina causing it to separate over the macula area.
Diagnosis is usually confirmed by fluorescein angiography. In this test, your retinal specialist is able to see a special dye accumulate at the location of the CSR.
Other tests, such as OCT, may also help in detecting the separation of the retina.
Symptoms of CSR include blurred vision, distorted vision, where objects appear smaller, and faded vision, where objects appear “washed out”.
Nearly 90% of people with CSR do not require any treatment, as it resolves within 6 months.
Removal of an epiretinal membrane requires surgery.
The first step involves breaking up the vitreous gel into small portions and removing it using a suction device. At the end of the surgery, the jelly is replaced with saline.
The second step involves detection and peeling of the epiretinal membrane. Special forceps are used to gently remove it from the underlying retina. A temporary air bubble may be placed in the eye. The air bubble can help smooth out the retina and prevent retinal detachment.
Vision can be blurred for 4 to 6 weeks. However, vision will not fully recover due to damage from the membrane to the retina.
Fluorescein angiography is a test used to assess blood flow in the retina and choroid. Blood flow is assessed using a camera that is able to visualise a special dye as it passes through blood vessels.
Before the test, your pupils will be dilated using drops. Then, just before the test, the fluorescein dye will be injected in your arm. It takes around 10 seconds for the dye to reach the eye. The angiography system will then record the flow of the dye, as it enters and leaves the blood vessels in the retina.
Fluorescein angiography is used to help in the diagnosis of various conditions affecting the retina. For example, in wet AMD, abnormal blood vessels can be detected leaking the dye below the macula.
Fluorescein angiography also helps detect areas in the retina, where blood flow has been blocked due to a variety of vascular conditions. Angiography also confirms the presence of conditions such as central serious retinopathy, which result in a pooling of the dye within the retina.
Intravitreal injections are a treatment for many retinal eye conditions where there are abnormal vessels growing under the retina, e.g. certain types of wet AMD. It is also a treatment for conditions that cause swelling at the macula. They may also be used in cases of inflammation and infection at the back of the eye.
After applying an anaesthetic to the front of the eye, the injection is delivered around 3-4mm from the edge of the cornea. The contents of the injection are delivered into the vitreous cavity inside the eye.
You may be asked to take antibiotic eye drops after the procedure.
A common symptom after the injection is the presence of a dark spot or small floaters. In addition, your eye pressure will be moderately elevated. You may also experience a transient decrease in vision and discomfort following the treatment.
However, if you are in pain or if you notice that vision has decreased significantly, you should contact your doctor immediately.
A macular hole most often affects people between the age of 60 to 80. They are twice as common in women compared to men. A macular hole forms at an area of the retina responsible for detailed vision. They are associated with persistent swelling of the central retina and the presence of significant myopia or short-sightedness.
When we need to see the fine detail, we use a specialised area on the retina, called the macula. In the early stages, vision may be slightly blurred and even distorted.
With age, the vitreous gel shrinks. Occasionally, the gel pulls on the macula. As it separates, it removes a section of the retina, resulting in a macular hole.
If a macular hole progresses, then vision will change and you will notice the presence of a central dark patch that moves with your eye.
Early treatment can reduce the risk of significant vision loss.
A Pigment Epithelial Detachment, or PED, forms below the retina. An accumulation of clear fluid builds up between the retina and the choroid. The fluid causes the retina to elevate over the macula.
Diagnosis is usually confirmed by fluorescein angiography. In this test, your retinal specialist is able to see a special dye accumulate at the location of the detachment.
Other tests, such as OCT, may also help in detecting the separation of the retina.
Symptoms include blurred vision, distorted vision, where objects appear smaller, and faded vision, where objects appear “washed out”.
A pigment epithelial detachment can occur in adults at any age.
However, in people over 55, it is associated with Age-related Macular Degeneration.
The retina is the thin, light detecting layer at the back of the eye.
Blood flows into the eye from the central retinal artery and out of the eye through the central retinal vein. A blockage to the retinal vein prevents blood from leaving the eye, causing it to leak onto the retina.
A blockage to a vein can occur because of a hardening of the arteries, which causes compression on a vein.
Several factors are related to retinal vein occlusion.
These include the presence of raised blood pressure and high cholesterol, glaucoma, diabetes, certain rare blood disorders, and smoking.
If a blockage occurs in one of the branches of the retinal vein, it results in a bleed in that area of the retina.
However, if it occurs in the main vein, it is called a central retinal vein occlusion, which generally results in more bleeding over the retina. Many people see a dark patch in their vision that moves with the eye.
The severity of the vison loss depends on the extent of the bleeding.
A retinal vein occlusion may not require any treatment as the blood absorbs.
If the bleed is located at or near the centre of vision, then it may cause a swelling in this area and permanent changes to vision.
Intravitreal injections can help improve central vision and stabilise any swelling.
Another complication is the growth of abnormal new blood vessels. These occur in about 20% of patients with retinal vein occlusion. The growth of these vessels can be stabilised with retinal laser treatment.
A number of procedures can be used to reattach a detached retina.
Scleral buckling involves attaching a silicone or sponge-like band to the tough outer layer of the eye, called the sclera. The buckle indents the sclera towards the detached retina.
Additional procedures may also be required to reattach the retina, such as an air bubble or retinal laser treatment.
Your surgeon will also prescribe various eye drops to help protect your eyes.
Although you will have some sight after surgery, it is difficult to predict how much you will see as everyone is unique. The recovery of vision is dependent on the extent of the retinal detachment and the surgical procedures used to repair the retina.
Immediately after the procedure, you will experience redness, bruising, and soreness, which will last for approximately one week. You may also experience a scratchy or itchy sensation from the disposable stitches. After a scleral buckle procedure, most people are able to return to work in around a week, but full recovery will take 4-6 weeks. During this period, avoid bending, lifting moderately heavy objects, driving, or strenuous activity. If your surgery involved placing an air or gas bubble inside the eye, you should not fly until the bubble has absorbed. You should also ask your retinal specialist when it is safe to fly.
If you notice vision deteriorating or if you have severe pain, contact your ophthalmologist immediately.
A vitrectomy is a surgical procedure to remove the vitreous humour inside the eye.
A vitrectomy may be required if these is a bleed in the jelly or after complications in the cataract surgery or in certain conditions affecting the retina. Once the jelly is removed, retinal surgery will be performed. The eye is then filled with saline or temporary silicone oil. A gas bubble may also be inserted to help flatten the retina. If oil or gas is used, you will be advised to position your head in a particular way. This should be maintained for around 1 to 3 weeks, as instructed by your doctor.