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.
All vision problems need not necessarily stem from the eye. Some vision problems involve the brain. Neuro ophthalmology is the sub specialty of both neurology and ophthalmology. A neuro ophthalmologist is a Physician who specializes in the diseases affecting vision that originates from the nervous system. Conditions such as optic nerve disorders, loss of vision from central nervous system disease, double vision diplopia and involuntary movement of the eyes nystagmus are some of the disorders under the purview of a neuro ophthalmologist. An ophthalmologist attends to patients with disease or injury in the eye ball, cornea and the lens or into the eyeball at the retina inside the eye. If any problem occurs behind the eye in the optic nerve or in some distinct visual pathways connecting the brain, it requires the special skills of a neuro ophthalmologist.
A neuro ophthalmologist could be an ophthalmologist or a neurologist with additional special training. After completing a residency program in any one of the two specialty areas, they take a fellowship in neuro ophthalmology for a year or two before starting to practice as a neuro ophthalmologist. A neuro ophthalmologist attends to a full spectrum of neuro ophthalmic conditions including evaluation, diagnostic and referral services of rare and complex disorders. A neuro ophthalmologist caters to:
- Patients who suddenly lose part of their side vision.
- Patients suffering from double vision.
- Patients with unequal pupils.
- A patient suffering form a stroke.
- A patient with brain tumor
- Patients who suddenly have their vision out of focus
- Any and every patient with unusual vision problems.
In addition to the above, a neuro ophthalmologist provides emergency evaluation of a wide variety of disease that can cause visual loss. Unexplained visual loss can arise out of uncommon disease conditions like myasthenia gravis, multiple sclerosis, mitochondrial disease and other muscular diseases that affect the eye. The neuro ophthalmologist uses special testing techniques including visual fields, visual evoked response, imaging studies such as CT, MRI and Angiography and ultrasound to diagnose the disease patterns. It becomes necessary for the neuro ophthalmologist to work closely with other medical specialists to offer multidisciplinary care and solution for complex cases.