Thoneh

RETINAL DISEASES

RETINAL DISEASES

The retina is the inner most layer of the eye and is the imaging centre.

Located at the back where the optic nerve is, the retina is responsible for turning light into nerve signals from the back wall of the eye to the area of the brain responsible for sight.

Conditions that can affect your retina (e.g. ageing, chronic diseases like diabetes and trauma to the eye) may lead to vision loss.

THONEH’s Consultant Ophthalmologists are well experienced in treating various retinal conditions to prevent vision loss. They are experts in their field using the latest technologies and best practices for diagnosis and management of these conditions.

 

The most common retinal conditions are:

Eye anatomy

What is diabetic retinopathy?

Diabetic retinopathy occurs when the blood vessels in the retina are damaged due to long-standing or uncontrolled diabetes.

  • This causes a leak of fluid and lipids from the blood vessels onto the macula.
  • In other cases, new and fragile blood vessels grow along the retina.
  • Without timely treatment, these new blood vessels can bleed, clouding vision and damaging the retina.
  • Scarring or detachment of the retina may occur causing leakages.

What are the symptoms and signs of diabetic retinopathy?

Unfortunately there are no signs or symptoms in the early stages of diabetic retinopathy.

As the damage to the retina progresses, symptoms that may be experienced are:

  • Blurring of vision
  • Difficulty reading
  • Sudden loss of vision in one eye
  • Floaters and flashes of light
  • Seeing “halos” around light sources

How is diabetic retinopathy treated?

Management of diabetes is crucial to prevent further loss of sight due to diabetic retinopathy.

Additionally, the following procedures can be carried out to repair the damage caused by the condition:

Intravitreal Anti-VEGF injections are given to patients …

  • Laser treatment is used to either seal leaking blood vessels or prevent new blood vessels from growing
  • Surgery is done in advanced cases to stop the bleeding and to remove the blood clots and fibrous tissue

If you have diabetes you should visit your ophthalmologist regularly to ensure that your retina is healthy.

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What are… Floaters

Flashes

 
  • Some people may experience small specks or clouds moving in their field of vision.
  • While these objects look like they are in front of the eyes, they are actually floating inside casting shadow on the retina.
  • Called floaters, they come in different shapes and sizes, such as little dots, circles, lines, clouds, or cobwebs.
  • They are often symptoms of retinal diseases.
  • When the vitreous gel inside your eye rubs or pulls on the retina, you may see what looks like flashing lights or lightening streaks.
  • If you have been hit in the eye, you may also experience flashes, seeing “stars”.

In some cases, these flashes can appear on and off for a long period of time, and is more common as we grow older.

What causes…
  • Floaters are actually tiny clumps of gel or cells inside the vitreous, the clear jelly-like fluid that fills the inside of your eye.
  • In 80% of the cases they form naturally as the vitreous begins to shrink.
  • In 20% of cases they can also be caused by:
    • Tears in the retina
    • Bleeding inside the eye
    • Inflammation
    • Infection
  • Like floaters, flashes can be caused by posterior vitreous detachment, when the vitreous gel pulls away from the back of the eye.
  • If you notice the sudden appearance of flashes, you should visit your Ophthalmologist immediately because it could indicate a retinal condition.

How are floaters and flashes treated?

Floaters

  • Floaters are usually harmless, and in the 90% of cases, can be left alone.
  • Troublesome floaters can be removed through Vitreolysis [link to laser treatment], a non-invasive and pain free procedure that eliminates the strands and improves vision.
  • In 10% of cases, floaters may indicate vitreoretinal diseases such as retinal tear or retinal hole, bleeding inside the eye, inflammation, and infection.

Flashes

  • A sudden appearance of flashes on the other hand should be seen to by an ophthalmologist immediately as it could indicate a retinal tear.

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What is retinal detachment?

Retinal detachment is the separation of the retina from its attachment on the back wall of the eyeball. It can cause the retina to lose its function or be damaged, and can lead to partial or complete loss of vision.

Causes and risk factors for retinal detachment are:

  1. Ageing – more common in people over the age of 50
  2. Extreme myopia (near-sightedness)
  3. Family history of retinal disease or detachment
  4. Previous or current severe injury to the eye
  5. Previous eye surgery such as cataract removal
  6. Advanced diabetes
  7. History of other eye disease or severe inflammation of the eye

What are the signs and symptoms of retinal detachment?

The symptoms and signs of retinal detachment are:

  • Frequent flashes of light, especially from the sides
  • Seeing floaters
  • Blurred vision
  • Partial loss of vision like a curtain closing down

If you have symptoms such as floaters and flashers, you should immediately visit your Ophthalmologist to ensure that your retina is still healthy and to prevent any vision loss.

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Introduction

Age-related Macular Degeneration (AMD) is a chronic eye disease and one of the leading causes of severe vision loss in people 60 years of age and above. It is also one of the leading causes of adult blindness in the world.

Contrary to what many believe, vision loss – and specifically AMD – does not have to be an inevitable consequence of ageing. Protect your vision by being active in your healthcare. Visit your eye doctor regularly. 

What is AMD?

AMD is a disease that can affect the sharp central vision needed for “straight-ahead” activities like reading, driving, telling time and recognize faces.

Sometimes AMD advances so slowly that you notice little change in vision. Sometimes AMD progresses quickly, resulting in rapid vision loss. AMD causes no pain, but can rob you of you ability to see what is on front of you. There are two types of AMD: Dry & Wet.

Dry AMD

In dry AMD, which makes up to about 85% of all AMD cases, the light-sensitive cells in the retina die, affecting “straight-ahead” vision. The most common symptom of dry AMD is blurred vision. Dry AMD tend to develop slowly, but may develop into a more severe form of AMD called wet AMD.

Wet AMD

Wet AMD, accounts for about 15% of all AMD cases, has abnormal blood vessels growing under the macula. This may lead to bleeding, scar formation and permanent damage. Damage occurs more rapidly than in the dry form and tends to lead to more severe loss of central or “straight-ahead” vision. If detected in time, relevant treatments may stop the progression of vision loss.

Am I at Risk?

The two greatest risk factors for developing AMD are:

  • Increasing age – about 25% of people over 65 years of age have AMD.
  • Having AMD in one eye – of those with AMD in one eye, about 40% wil develop AMD in the other eye within five years.

Other risk factors for developing AMD include:

  • Smoking
  • Race – Caucasians appears to have higher risk
  • A family history of the disease
  • Low dietary intake of certain vitamins and minerals
  • Gender – women appear to be at greater risk than man

Am I Seeing These Symptoms?

Symptoms of AMD include:

  • Decreased Visual Acuity
    • Dim, or less sharp central or “straight-ahead” vision
  • Loss Of Contrast Sensitivity
    • Colors that seem washed out or dull
  • Central Scotoma
    • A blank or blind spot in your central vision
  • Metamorphopsia
    • Seeing objects as wavy or curved.

How is WET AMD Diagnosed?

  1. Fundus Photography
  2. Fluorescein Angiography. This is a test which provides information about the blood circulation in the retina that cannot be seen by routine eye examinations. The Fluorescein dye is injected into the blood via a vein in the arm and rapidly reaches the eye. The dye circulates through the retina and highlights any abnormalities or damage. The abnormal new blood vessels seen in Wet AMD have weak, fragile walls and the dye leaks through them, outlining them clearly.
  3. Indocyanine Green Angiography. Indocyanine Green (ICG) Angiography has different properties to Fluorescein and highlights the deeper layer of the retina and the choroidal circulation (the source of the abnormal blood vessels), which is normally hidden from view. It enables different types of new vessels to be identified.
  4. Optical Coherence Tomography. Optical Coherence Tomography (OCT) is a non-invasive diagnostic imaging technique that uses light to produce very high-resolution cross-sectional images of the tissue layers within the retina. These layers at the macula can then be studied and measured in microscopic detail. By comparing the structure and the thickness of the layers measured by the OCT against a normal healthy retina, eye specialists can detect any Wet AMD even at a very early stage.
  5. Optical Coherence Tomography Angiography. Optical Coherence Tomography Angiography (OCTA) is a fast, new imaging modality, which uses the principles of OCT to define the retinal vascular structure, using sequential B-scan to detect blood flow. En face images can then be generated showing the superficial and deep retinal capillary plexus and the choroid. Cross-sectional OCT combined with depiction of flow can help demonstrate the location of the vascular abnormality. Although OCTA detects neovascular AMD by detecting flow in a vascular complex, it does not show leakage.

How can AMD be Treated?

AMD causes permanent vision loss. Successful treatment can stabilize and /or slow vision loss or in some cases, restore vision. Although new treatments are always being researched, treatment options today are:

  • Anti-VEGF Injection. The new blood vessels are prompted to grow by a protein called Vascular Endothelial Growth Factor (VEGF). Anti-VEGF drug is injected into the eye to block the protein responsible for the growth of new blood vessels. Anti-VEGF drug is injected into the cavity where it can spread to the retina. The injections are generally administered at four to six week intervals. 
  • Photodynamic therapy, used to help treat wet AMD. In this procedure, a light-activated drug is injected into the blood stream and travels to the abnormal blood vessels in the eyes. It is then activated in the eye by a non-heat laser to help reduce the risk of further vision loss. PDT is no longer used as a monotherapy as patients continue to lose vision in the first six months. If used in conjunction with Anti-VEGF this vision loss can be prevented. There is one type of new vessels called polypoidal vascular choroidapathy for which this combination may be preferable to giving Anti-VEGF by itself.
  • Laser photocoagulation. In this procedure, a high-energy beam of light is used to destroy leaky blood vessels, preventing further loss of vision. Through heat, the treatment damages the retina at the treatment spot, producing scars. Therefore it should only be used for treating new vessels that are not under the central macula. This treatment is only for a small percentage of patients with a particular type of AMD.
  • Optical Aids and Lights. Low vision optical aids often improve vision for people with macular degeneration. Many different types of magnifying devices are available. Spectacles, hand or stand magnifiers, telescope, and closed circuit television for viewing objects are some of the available resources. Aids are prescribed by your ophthalmologist or by referral to a low vision center. Bright illumination properly directed for reading and close work are often beneficial. Special lamps can also be helpful. Books, newspapers, and other items available in large print offer further help. A patient with macular degeneration can be helped. Fortunately, visual aids are available to assist many patients in leading a comfortable and relatively normal life. With these devices and proper motivation, people with visual loss can often read, do modified close-up work, and continue to take care of themselves.
  • If you are over the age of 50, or if your family has a history of retinal problems, you should have your eyes checked periodically for signs of eye problems like macular degeneration. Early detection and subsequent treatment if indicated, may help prevent additional visual loss. If you have additional questions or would like any further informations, contact your ophthalmologist.

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DR. PALL SINGH

Senior Consultant Ophthalmologist

DR. V. GAYATRI DEVI

Senior Consultant Ophthalmologist

DR HARI KRISHNAN

Senior Consultant Ophthalmologist

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