Many retinal disease, like diabetic retinopathy, retinal vein occlusion, and retinopathy of prematurity, compromise the retinal circulation and can cause vision loss from retinal neovascularization.

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Retinal neovascularization refers to the abnormal growth of new blood vessels in the retina, which is the light-sensitive tissue at the back of the eye. This process is not part of normal vascular development and can have detrimental effects on vision. Retinal neovascularization is often associated with poor circulation in the retina, and it can occur in various diseases. Here’s an explanation of how it occurs and its relationship with poor circulation:

  1. Poor Circulation and Ischemia:
    • Poor circulation in the retina, leading to inadequate blood supply (ischemia), is a common trigger for retinal neovascularization.
    • When the retina is not receiving enough oxygen and nutrients due to compromised blood flow, it responds by releasing signaling molecules, such as vascular endothelial growth factor (VEGF), to stimulate the growth of new blood vessels.
  2. Diseases Associated with Retinal Neovascularization:
    • Proliferative Diabetic Retinopathy (PDR): Diabetes can lead to damage to the small blood vessels in the retina, causing ischemia. In response, the retina may develop abnormal new blood vessels, contributing to PDR.
    • Retinal Vein Occlusions (Branch Retinal Vein Occlusion (BRVO) and Central Retinal Vein Occlusion (CRVO)): Obstruction of retinal veins can result in poor blood circulation and ischemia. Retinal neovascularization may occur as a response to the ischemic stimulus.
    • Sickle Cell Retinopathy: Sickle cell disease can cause vaso-occlusion in the retinal vessels, leading to ischemia. This ischemia can trigger the growth of abnormal blood vessels in the retina.
    • Retinopathy of Prematurity (ROP): Premature infants with underdeveloped retinas may experience poor circulation, and as a response, abnormal blood vessels can proliferate, contributing to ROP.
  3. Mechanism of Retinal Neovascularization:
    • Ischemia-induced release of growth factors, particularly VEGF, plays a central role in the development of retinal neovascularization.
    • VEGF stimulates the formation of new blood vessels, a process known as angiogenesis. However, in the context of retinal neovascularization, these new vessels are abnormal and may be fragile, leading to potential complications such as bleeding and scarring.
  4. Consequences and Damage to the Retina:
    • Retinal neovascularization can have serious consequences for vision. The abnormal blood vessels are prone to leakage, causing fluid accumulation in the retina, which can lead to macular edema.
    • The new vessels may also bleed, resulting in vitreous hemorrhage, and they can contribute to the formation of fibrous scar tissue, leading to tractional retinal detachment.

In summary, retinal neovascularization is a pathological response to poor circulation in the retina, often triggered by various diseases. The abnormal blood vessel growth can lead to complications that may severely impact vision, making understanding and managing the underlying diseases critical for preventing or addressing retinal neovascularization.


Anti-VEGF (vascular endothelial growth factor) injections have become a standard and effective treatment for retinal neovascularization associated with various eye diseases. These injections aim to inhibit the action of VEGF, a key molecule involved in the abnormal growth of blood vessels. Here’s an overview of how anti-VEGF therapy is used to treat retinal neovascularization, including the diseases involved, the benefits, and potential risks:

  1. Diseases Treated with Anti-VEGF Injections:
    • Proliferative Diabetic Retinopathy (PDR): In PDR, abnormal blood vessels grow in the retina due to diabetes-induced ischemia. Anti-VEGF injections can help control the neovascularization and reduce the risk of complications.
    • Retinal Vein Occlusions (Branch Retinal Vein Occlusion (BRVO) and Central Retinal Vein Occlusion (CRVO)): Retinal vein occlusions can lead to ischemia and VEGF release, resulting in abnormal vessel growth. Anti-VEGF therapy is used to manage neovascularization in these cases.
    • Retinopathy of Prematurity (ROP): In premature infants, abnormal vessel growth in the retina can be treated with anti-VEGF injections to prevent complications associated with neovascularization.
  2. Benefit of Treatment:
    • The primary benefit of anti-VEGF therapy is the inhibition of abnormal blood vessel growth in the retina. By blocking the action of VEGF, these injections help reduce leakage, bleeding, and the formation of fibrous scar tissue.
    • Anti-VEGF treatment is effective in preserving or improving vision by preventing or treating complications associated with retinal neovascularization, such as macular edema, vitreous hemorrhage, and tractional retinal detachment.
  3. Risks and Considerations:
    • While anti-VEGF injections are generally considered safe and well-tolerated, there are potential risks and considerations:
      • Infection: Any injection carries a small risk of infection. Proper sterile techniques and monitoring help mitigate this risk.
      • Increased Intraocular Pressure: Some individuals may experience a temporary increase in intraocular pressure, requiring monitoring, especially in those with pre-existing glaucoma.
      • Inflammatory Reactions: Inflammatory responses in the eye are rare but possible. Regular follow-up appointments help detect and manage any adverse reactions.
      • Systemic Effects: Although anti-VEGF agents are primarily targeted to the eye, there is a theoretical risk of systemic effects. However, the systemic exposure is generally low.
  4. Treatment Course:
    • Anti-VEGF injections are typically administered as a series of injections over several months. The treatment frequency and duration depend on the specific disease and the individual patient’s response.
  5. Combination Therapies:
    • In some cases, anti-VEGF injections may be used in combination with other treatments, such as laser therapy, to achieve optimal outcomes.

It’s crucial for individuals undergoing anti-VEGF therapy to have regular follow-up appointments with their eye care professionals to monitor the response to treatment and address any potential complications. The decision to use anti-VEGF therapy is made based on the specific characteristics of the disease and the patient’s overall health.


Panretinal photocoagulation (PRP) is a laser treatment that can be used to manage various retinal diseases by reducing the growth of abnormal blood vessels and preventing complications. Here’s an overview of how PRP is applied in different diseases:

  1. Proliferative Diabetic Retinopathy (PDR):
    • Pathology: PDR is characterized by the growth of abnormal blood vessels on the retina due to ischemia (inadequate blood supply) caused by diabetes.
    • PRP Benefit: PRP is applied to the peripheral retina to reduce ischemia, inhibiting the stimulus for abnormal vessel growth. It helps prevent bleeding, scar tissue formation, and vision loss associated with advanced diabetic retinopathy.
  2. Branch Retinal Vein Occlusion (BRVO) and Central Retinal Vein Occlusion (CRVO):
    • Pathology: These conditions involve blockages in retinal veins, leading to poor blood flow, ischemia, and the release of vascular endothelial growth factor (VEGF).
    • PRP Benefit: PRP can be used to reduce ischemia and downregulate VEGF production. It helps control neovascularization (abnormal vessel formation) and decreases the risk of complications like macular edema and neovascular glaucoma.
  3. Sickle Retinopathy:
    • Pathology: Sickle cell disease can cause damage to blood vessels, leading to ischemia and neovascularization in the retina.
    • PRP Benefit: PRP can be employed to treat areas of ischemia, reducing the stimulus for abnormal blood vessel growth. It helps prevent complications such as vitreous hemorrhage and retinal detachment.
  4. Coats’ Disease:
    • Pathology: Coats’ disease is characterized by abnormal retinal blood vessel development, leading to leakage and fluid accumulation in the retina.
    • PRP Benefit: PRP can be used to treat the abnormal blood vessels, reducing leakage and preventing complications such as retinal detachment. It helps preserve vision by controlling the disease’s progression.
  5. Retinopathy of Prematurity (ROP):
    • Pathology: ROP occurs in premature infants and involves abnormal vessel growth in the retina.
    • PRP Benefit: PRP is used to treat the peripheral retina, reducing the stimulus for abnormal vessel growth. It helps prevent complications like retinal detachment and preserves vision in premature infants.

In these diseases, the laser’s ability to destroy ischemic retina is crucial in reducing the stimulus for abnormal vessel growth. Additionally, PRP can downregulate VEGF production, which plays a key role in promoting neovascularization. By targeting the ischemic areas and suppressing VEGF, PRP helps prevent complications and preserve vision in these various retinal conditions. However, the decision to use PRP depends on the specific characteristics of each disease and the individual patient’s condition, and it is typically determined by the treating ophthalmologist


Treatment of retinal neovascularization, like anti-VEGF therapy or panretinal photocoagulation reduces the risk of severe vision loss in patients with high risk eyes.   Prior to the discovery of panretinal photocoagulation, it was not uncommon for diabetics to be blind and need a white cane. Today, that level of blindness is very rare.



Panretinal photocoagulation can decrease the reading vision in younger patients making them need reading glasses. It can also cause a slight dilation of the pupil. Macular edema occurs in some patients after panretinal photocoagulation but almost always responds to treatment.