Fluorescein Angiography

Fluorescein Angiography is a diagnostic test that aids visualization of the blood circulation in the retina and choroid. Fluorescein is a water-soluble dye that is injected into a vein in the patient's arm. It travels through the blood vessels of the body thereby aiding multiple photographing of the retina. The images obtained help in detecting any swelling or leakage in the blood vessels. The patient's eyes are dilated with mydriatic eye drops so that photographs of the inside of the eye can be taken.

Some patients may notice skin rash, itching or allergic reaction to the dye. Nausea or vomiting may be noticed. But this non-invasive test can usually be safely repeated. Abnormal results of fluorescein angiography test may indicate diabetic retinopathy, macular degeneration, or cancer. Ischaemia or edema in the retina circulation can be detected with the help of fluorescein angiography.

Central Serous Retinopathy

Central serous retinopathy or CSR is associated with serous fluid accumulation below the retina in the macula at the back of the eye. The retina is an important structure of the eye, which facilitates the signal conversion of light to electrical impulses transcribed to the brain. This is because of its photosensitive nature. In CSR the retinal layer is slowly damaged and distorted because of fluid accumulation.

CSR is triggered by the onset of edematous fluid accumulation under the retinal layer. Studies indicate the involvement of the choroid tissue blood vessels, which are responsible largely for the fluid accumulation. The tissue injury and fluid accumulation affects the retinal epithelial tissue causing disturbance in vision. This avascular focal leakage caused in the retinal pigment epithelium triggers the distortion of the neuron-sensory retina. In some cases, this damage caused is self-limiting and recovery is possible. In case of adverse effects such as atrophy, neuron-sensory damage can cause permanent loss of vision.

Causes and Clinical manifestations

CSR is associated with central vision impairment as the zone of fluid accumulation is the choroid region followed by the retinal epithelium. Many studies indicate the effect of cortisol on the incidence of CSR. Cortisol is an adrenal hormone triggered in the event of stress. The hormone thus produced can cause blood vessel damage. Although the actual cause of CSR still remains controversial, it is believed that cortisol, epinephrine and external steroid applications can induce the condition.

CSR is usually noticed in the age groups of 20-50 and it has no ethnic specificity. This might be suggestive of the increasingly stressful lifestyle, which is a possible trigger for CSR. CSR is more common among men than women. Usually people who face severe stress - like pilots, police officers or soldiers may face this condition, which can be self limiting in some cases. The symptoms fade away after a few months. The complications associated with CSR include blurred vision, blind spot, distorted vision and hazy appearance of objects at a distance. Symptoms of Central serous retinopathy include patch in central vision, reduced color vision and changes in image size.

Diagnosis and Treatment

CSR is diagnosed based upon optometric tests. Some of the common tests include optical coherence tomography (OCT) which is used determine the amount of fluid under the retinal layer caused because of trauma, inflammation or infection. Fluorescein Angiography enables location of the exact point of fluid leakage. Indocyanine green angiography determines the vascular abnormalities associated with respective tissue. Since the CSR is related to leakage of fluids from vascular regions, photodynamic treatment is suggested to seal the respective regions by administering laser. In most cases of CSR, the symptoms and the condition disappear after 3 months with full restoration of vision. But it may recur at some time later in some cases. The only known complications of CSR therapy include grey spots and eye irritations.

Diabetic Retinopathy

Diabetic Retinopathy is a common complication with Diabetes where the production or use of insulin levels are not regulated resulting in fluctuating blood sugar levels. Diabetic Retinopathy results in 90% of the cases of type 1 Diabetes and 65% of the cases of type 2 diabetes. Retinopathy is the damage or hemorrhaging of small blood vessels of the retina. It is a non-inflammatory disease of the retina. There are many types of retinopathy. Non Proliferative Retinopathy refers to the condition where the damaged or leaking vessels do not spread. Symptoms include vision spots, loss of vision in some cases, floaters - floating regions of blurred vision or loss of fine vision. On the other hand, Proliferative Retinopathy refers to the spread of the damaged retina - specifically the rupture of the newly formed blood vessels resulting in sudden loss of vision.

Hardening of the retinal arteries is known as Arteriosclerotic Retinopathy. Increased pressure in the affected region may result in the retina detaching itself from the back of the eye that can cause partial or total blindness.

Hypertensive Retinopathy: Hypertension can cause damage to the blood vessels of retina resulting in Hypertensive Retinopathy which has symptoms that include blurred vision or decreased visual perception.

Risk Factors for Retinopathy

• Diabetes mellitus
  
• Hypertension
  
• Hypercoagulability (abnormal tendency of the blood to clot - thrombosis), Thrombophilia
  
• Hyperlipidemia (Abnormally high blood lipid levels)
  
• Hyperviscosity
  
• Trauma
  

Diagnosis and Treatment

Retinal Specialists may use ophthalmoscope or Fluorescein Angiography for a detailed evaluation of the eye condition. Laser Surgery is usually the first choice of treatment to seal the bleeding blood vessels in the retina (retinal hemorrhages). Treatment of diabetic retinopathy would also involve treating the overall condition. Nutritional supplements like Vitamins A, C, E and Lutein may also be tried.