Diagnostic tests

Fluorescein angiography (FA)

Fluorescein angiography (FA) is a commonly used diagnostic test that your doctor might order to determine treatment options for diabetic retinopathy, macula edema, vein occlusions, macular holes, and macular degeneration.

How is fluorescein angiography performed?

  • Drops are placed into your eye to make your pupils dilate
  • A small amount of fluorescein dye in injected into a vein
  • A series of picture are taken of the back of the eye as the dye passes through the retinal circulation.
  • The entire procedure lasts approximated 10 minutes
  • The images are processed by a computer and are immediately available for review by the physician.

Are there any side effect?

This is typically a very safe procedure, but there are some side effects.

  • Sodium fluorescein is a vegetable based, water soluble dye that can cause yellowing of the skin. This typically lasts several hours. The dye is removed from the body by your kidneys. This will cause your urine to turn yellow for up to 2 days.
  • During the injection, some patients may notice a very slight wave of nausea that lasts only a few seconds. Reactions to nausea vary from each individual.
  • Allergic reactions to this dye are extremely rare. An allergy to the dye will happen within minutes of the injection. In most cases, allergies are mild and manifest with symptoms such as itching and hives. Rarely, more severe reactions do occur. Notify your doctor immediately if you experience itching, hives, swelling of the tongue, and difficulty breathing.
  • Your vision may be blurry after the test due to the dilation of the pupils and the flash from the camera.

Are there any contraindications to this test?

  • Notify your doctor of any previous adverse reaction or allergic symptoms to fluorescein angiogram.
  • While there is no data on the use of this dye on pregnant patients, it is best to avoid using this test on patients who are pregnant, think they are pregnant, or breast-feeding.
  • There are no special instructions before or after this test and there are no contraindications to any medication you take.

Optical Coherence Tomography (OCT)

Optical Coherence Tomography (OCT) is a modern imaging technique that uses a beam of laser light to create a high resolution cross-sectional image of the retina. It is often used in conjunction with fluorescein angiograaphy to help diagnose and guide treatment of diseases affecting the macula, such as AMD, macular edema, epiretinal membrane, and macular holes.

oct

OCT testing is non-invasive and completely painless. A typical test takes 1-2 minutes and the results are available instantly.

Ultra-sonography

Ultra-sonography is a non-invasive test which uses high frequency sound to image the intra-ocular anatomy. A pen-like probe is place over the closed eyelid or directly on the anesthetized eye. The tip of the probe transmits a high frequency sound which is transmitted through the eye. As the sound is reflected off the surfaces of the eye, a detector on the probe measures the time it takes for the sound to be reflected back. This information is processed by a computer which then displays an image of the eye.

What are the indications of ultra-sonography?

Ultrasonography is indicated when your doctor cannot see your retina, or he needs to measure the height of a tumor in the eye.  Common causes of poor or obstructed view of the retina include:

  • Vitreous hemorrhage  (or bleeding into the vitreous cavity). This can occur in patients who have diabetic retinopathy, retinal tears or detachment, or trauma.
  • Severe inflammation in conditions such as endophthalmitis or uveitis.
  • Dense cataracts or severe corneal scarring.
  • When your doctor wants to characterize and measure certain structures in the eye.
  • Tumors or suspected intraocular tumors

What are the limitations of ultra-sonography?

Ultra-sonography gives a cross-sectional view of the intraocular anatomy. Although modern ultrasound machines have resolution on a scall of microns, minute details of the eye can be difficult to characterize. Furthermore, ultrasound images cannot determine the function of the imaged structure. The information provided by ultra-sonography is taken in conjunction with the clinical exam to help determine the patient’s diagnosis.