Retina

The retina is in the back of the eye. The retina is like the film in a camera which records a picture when light interacts with the film. In the same way, when light interacts with the retina a picture is taken which is then sent to the back of our brain where the picture is interpreted by the visual cortex of our brain.

The retina is actually neuro-sensory tissue, an extension of the brain. During an eye examination, the retina, blood vessels and optic nerve are all examined and may reveal changes that indicate disease processes elsewhere in the body.

If you have been referred to a retina specialist, you should make and keep such an appointment. Many serious and vision threatening conditions may be able to be treated by a retina specialist.

Macular Degeneration

Age-related macular degeneration (AMD) is a deterioration of the macula, a small area of the retina in the back of the eye which is responsible for central vision. Macula degenerates affects central vision and causes the following symptoms:

Usually side or peripheral vision is not affected. Many people are not even aware they have macular degeneration until they have noticeable visions problems or until it is detected during an eye examination.

Drusen

Drusen are small deposits of lipid and protein material that collect under the retina during the very early phase of macular degeneration. Usually drusen do not affect the vision and most patients are completely unaware they are present. Many patients with drusen do not develop either dry or wet macular degeneration.

Dry Macular Degeneration

Dry macular degeneration is the most common type of degeneration of the macula. About 80% (8 out of 10) of people who have AMD have the dry form. Dry AMD is when parts of the macula get thinner with age and tiny clumps of protein called druse grow. Often central vision is minimally affect and changes slowly if it is affected. There is no way to treat dry AMD yet.

Wet Macular Degeneration

This form is less common but much more serious. Wet AMD is when new, abnormal blood vessels grow under the retina. These vessels may leak blood or other fluids, causing swelling of the retina and eventual scarring of the macula. You lose vision loss is usually faster with wet AMD than with dry AMD.

Many people don’t realize they have AMD until their vision is very blurry. This is why it is important to have regular visits to an ophthalmologist. He or she can look for early signs of AMD before you have any vision problems.

Who Is at Risk for AMD?

You are more likely to develop AMD if you:

Having heart disease is another risk factor for AMD, as is having high cholesterol levels. Caucasians (white people) also have an elevated risk of getting AMD.

Ampler Grid (Macular Degeneration Detection)

The Ampler grid is a simple, but very effective device for detecting and monitor macular degeneration. The grid is white lines on a black background.

Normal Test: The lines are straight and the boxes square and complete.

Abnormal Test: The lines are bent or crooked and the squares missing or distorted.

Changes in the Ampler grid test may indicate changes taking place in the retina, specifically leakage of fluid under the retina causing distortion and eventual permanent scarring of the macula. Consult with your eye doctor if you notice Amsler grid changes.

Amsler Grid Instructions:

  1. Hold at reading distance, under good light, with reading glasses on.
  2. Cover one eye and look at the center white dot.
  3. Note any irregularities or blank areas in horizontal and vertical lines.
  4. Test the other eye.
  5. Test each eye at least once a week if you have known ARMD.

Floaters and Flashes

Floaters describe small specks or cob-webs that are seen in one’s field of vision when looking at a plain background, such as a blank wall or blue sky. Floaters are actually shadows created by cells or clumps of cells or material inside the vitreous gel-like fluid that fills the inside of the eye.

Flashing lights or lightening streaks can occur when the vitreous gel pulls on the retina as one looks from side to side. These flashes are similar to when one has been hit in the eye and one “sees” stars. These flashes of light usually occur when a vitreous separation occurs in the back of the eye and they can appear on and off for several weeks, sometimes for months after a separation has occurred.

Vitreous Separation or Detachment:

As we grow older, the vitreous gel gradually pulls away from the inside surface of the eye and may actually detach from its attachments in the back of the eye. This detachment can cause an increase in floaters and occasional flashes of light in our peripheral vision. Usually the vitreous pulls away from the retina without causing problems.

Retinal Hole:

But sometimes the vitreous pulls hard enough on the retina to actually create a tear or hole. Often when this happens many little floaters will be seen, often described as a “million little ants in one’s vision”. A retinal hole or tear is a serious problem that can lead to a retinal detachment and needs to be diagnosed early and repaired quickly by a retinal specialist.

Retinal Detachment:

Fluid can passes through a retinal tear and lift the retina off the back of the eye, just like wallpaper pealing off a wall. When the retina is lifted off the back of the eye it is called a retinal detachment. A retinal detachment is a vision threatening problem that needs to be diagnosed early and repaired quickly by a retinal specialist.

Sudden new floater and/or flashes may indicate the development of a retinal detachment and should be checked by your eye doctor.

Call Genstler Eye Center at (541) 928-1667 and request an appointment for an evaluation to make sure a retinal detachment has not occurred.

Diabetic Retinopathy

Poorly controlled blood sugar, over time, damages small blood vessels in the retina, the heart, the kidneys, and the lower extremities.

In the eye, these damaged blood vessels leak lipid, serum, and even blood into the retina and causes diabetic retinopathy. Sometimes these damaged blood vessels actually grow new blood vessels on the surface of the retina that cause retinal scarring. Rupture of these abnormal blood vessels can cause vitreous hemorrhage.

Controlled blood sugar minimizes blood vessel damage and decreases the risk of diabetic retinopathy.

Diabetic retinopathy usually affects both eyes. In the early stages of the disease, people are often unaware of any problem developing in the back of their eyes. As the disease progresses, vision blurring or loss develops, sometimes in a very short period of time.

Prevention is the best treatment for diabetic retinopathy. Strict blood sugar control significantly reduces the long-term risk of vision loss from diabetic retinopathy. Treatment usually will not reverse diabetic retinopathy, nor does it restore lost vision, but it may slow the progression of vision loss. Without treatment, diabetic retinopathy steadily progresses from minimal to severe states and can result in blindness.

Diagnostic Testing

The retina in the back of the eye can be difficult to examine at times. Fortunately, modern technology has developed amazing diagnostic equipment that help eye doctors sort out the cause of unexplained visual changes. Sometimes a referral to a retina specialist is required.

Examination of the retina usually requires dilation of the pupil so the eye doctor can get a complete view of your retina through your pupil. Some of the equipment used to assist the eye doctor to evaluate the retina are:

Optical Coherence Tomography (OCT)

This test creates a cross-section image of the macula, retina and optic nerve so the shape and thickness of the retina can be seen.

The Optical Coherence Tomography, usually called OCT is a valuable non-invasive test that can be performed on the same day of your appointment. This test detects swelling, traction or holes in the retina and measures the response to treatment for various retinal conditions. The test can be completed in minutes and can be done both with and without dilation or the pupil.

Fundus Photography

Fundus photography involves using high powered lenses and digital cameras to document changes, deterioration or damage to the retina, blood vessels and optic nerve that sometimes occur at the microscopic level. These digital pictures document a baseline at the initial examination that can be compared to subsequent pictures that document responses to treatment over time.

Many vision problems develop gradually over long periods of time. This makes early detection and monitoring critical in helping your eye doctor make important decisions about your vision. Fundus Photography is one of the best methods of recording and tracking such progressive diseases of the eye.

FA – Fluorescein Angiography (Retinal consult)

The blood vessel to the retina are critical to maintaining a healthy retina. Fluorescein angiography provides valuable information to retina specialist about the circulation of the eye and how it is affected by many conditions that occur in the back of the eye.

Fluorescein Angiography is performed by injecting a special dye into the arm. Within a few seconds, the dye travels through the circulatory system, and into the eye through the retinal vessels, and into a deeper layer called the choroid.

A specially equipped camera then captures a series of photographs of the dye as it circulates though the retina and choroid. These photographs can reveal to the doctor signs of circulation problems, swelling, leakage, or abnormal blood vessel formation.

This information allows the doctor to make a more accurate diagnosis, and help determine the exact area to be treated for conditions like macular degeneration, and diabetic retinopathy. The dye is considered safe, and serious side effects from the dye are rare.