Diabetic Retinopathy and Laser Treatment
Structure of the Eye
The eye consists of:
- Cornea (the transparent front layer)
- Iris (colored part of the eye)
- Pupil (central opening in the iris)
- Lens (behind the iris and pupil)
- Aqueous humor (fluid filling the space between the cornea and lens)
- Retina (innermost nerve layer, containing the macula for detailed vision)
- Optic nerve (transmits visual signals to the brain)
The tear film protects the eye, prevents infections, and nourishes the surface.
Diabetes and Its Impact on the Eye
Diabetes is a well-known condition, and with advancements in insulin and medication, patients now live longer. However, chronic diabetes leads to complications affecting small blood vessels, including those in the kidneys, muscles, skin, and retina (diabetic retinopathy).
Types of Diabetes
- Type 1 Diabetes – Insulin-dependent, occurs in children.
- Type 2 Diabetes – More common in adults, not always insulin-dependent.
Approximately 2.5-3% of the population has diabetes, with 10% being Type 1 and the rest Type 2.
Diabetic retinopathy is a progressive eye disease caused by damage to the small blood vessels in the retina, leading to fluid leakage, hemorrhages, and abnormal blood vessel growth.
🔹 5-year diabetics: 5% show retinopathy
🔹 15-year diabetics: 62% develop retinopathy
Mechanism of Disease Progression
Chronically high blood sugar levels cause:
✔ Structural changes in small blood vessels
✔ Thickening of vessel walls
✔ Damage to endothelial cells
✔ Leakage of blood and proteins into the retina
Diabetes-Related Eye Conditions
1. Tear Film Changes
✔ Reduced tear production leads to dry eye syndrome.
✔ Increased risk of infections due to reduced antibacterial properties of tears.
2. Glaucoma (Increased Eye Pressure)
✔ Higher prevalence of glaucoma in diabetics.
✔ Fluid accumulation in blood vessels can cause angle closure glaucoma.
✔ Abnormal new vessels can block drainage channels, increasing eye pressure.
✔ Treated with laser therapy and intraocular pressure-lowering medications.
3. Nerve and Muscle Paralysis
✔ Blocked blood flow to eye muscles can cause paralysis, leading to:
🔹 Painful eye movement
🔹 Double vision
✔ Treated with medications or surgery if unresolved in 6 months.
4. Optic Nerve Disease (Papillopathy)
✔ Swelling of the optic nerve head in both eyes.
✔ Temporary vision loss, usually improving within 3 months.
Diabetic Retinopathy
Diabetic retinopathy results from damage to the retina’s blood vessels, leading to:
✔ Retinal swelling (macular edema)
✔ Hemorrhages (retinal bleeding)
✔ Protein and fat accumulation in the retina
Advanced Stages Can Lead To:
✔ Severe hemorrhages
✔ Glaucoma
✔ Vision loss
Risk Factors for Diabetic Retinopathy
🔴 Long-term diabetes (>10 years)
🔴 High blood sugar levels
🔴 Fluctuating blood sugar
🔴 Hypertension
🔴 Anemia
🔴 High cholesterol
🔴 Diabetic kidney disease
🔴 Younger age of onset
Protective Factors
🟢 Older age (>70 years)
🟢 High eye pressure
🟢 Narrowed carotid arteries
Diagnosis of Diabetic Retinopathy
✔ Visual acuity test
✔ Anterior segment examination (lens and pressure evaluation)
✔ Indirect ophthalmoscopy (retina and optic nerve assessment)
✔ Fluorescein angiography (fundus imaging)
✔ Optical coherence tomography (OCT scan)
Treatment of Diabetic Retinopathy
🚨 Primary goal: Prevent disease progression rather than restore vision.
✔ Control blood sugar, blood pressure, anemia, and cholesterol.
✔ Treatment includes laser therapy, injections, or surgery.
Laser Treatment for Diabetic Retinopathy
Mechanism of Laser Therapy (Photocoagulation)
✔ Uses a 514 nm wavelength laser
✔ Targets retinal pigment cells, generating heat
✔ Destroys abnormal blood vessels
✔ Increases oxygen supply to the retina
✔ Reduces retinal swelling and prevents further hemorrhages
Candidates for Laser Therapy
✔ Clinically significant diabetic retinopathy (fluid accumulation and protein deposits in the retina).
✔ Diffuse macular edema (extensive retinal swelling).
✔ Abnormal blood vessel growth causing glaucoma.
Laser Therapy Side Effects
❌ Peripheral vision loss
❌ Night vision impairment
❌ Reduced contrast sensitivity
❌ Temporary increase in nearsightedness (myopia)
❌ Color vision disturbances
❌ Mild pain during treatment
❌ Glaucoma due to fluid retention
❌ Cataract formation
❌ Scar tissue formation affecting central vision
❌ Retinal detachment in rare cases
Surgical Treatment: Vitrectomy
🔹 Indicated for:
✔ Persistent vitreous hemorrhages (>3 months)
✔ Scar tissue pulling on the retina
✔ Retinal detachment due to traction
✔ Glaucoma from abnormal blood vessels
✔ Severe macular edema caused by fibrotic bands
🔹 Procedure:
✔ Small incisions made in the eye
✔ Hemorrhages and scar tissue removed
✔ Gas or silicone injected to stabilize the retina
Anti-VEGF Therapy
✔ Diabetics produce VEGF (Vascular Endothelial Growth Factor), which promotes abnormal blood vessels.
✔ Anti-VEGF injections prevent retinal bleeding and leakage.
✔ Helps reduce diabetic macular edema.
Intravitreal Corticosteroid Therapy
✔ Steroid injections reduce retinal inflammation and leakage.
✔ Effects last 3-6 months, requiring repeated doses.
✔ Used for cases unresponsive to laser or Anti-VEGF treatment.
Conclusion
🔹 Diabetic Retinopathy is a leading cause of vision loss in diabetics.
🔹 Early diagnosis and proper treatment prevent severe complications.
🔹 Laser therapy, anti-VEGF injections, and vitrectomy surgery are key treatment options.
🔹 Strict blood sugar and blood pressure control are essential for preventing progression.
Regular eye check-ups are crucial for diabetics to protect their vision!
