Intra-Vitreal Injections are given for different reasons in the eye.
The most common indications are :
Age Related Macular Degeneration - (wet / neovascular AMD)
Diabetic Macular Edema (DME)
Branch or Central Retinal Vein Occlusion (BRVO / CRVO) with Macular Edema
Medicines when given via eyedrops for these retinal conditions are not found to be effective. And therefore the need to give them via an injection.
Retinal cells or Photoreceptors - are neural cells - being very sensitive, and undergo degeneration when affected by the above conditions. Therefore, if indicated, the injections are best planned earliest possible.
wet AMD:
New abnormal blood vessels cause swelling in the central part of the retina, called macula. Macula is responsible for the most precise aspect of our vision, therefore new abnormal vessels at the macula, affect central vision drastically.
Macular Edema:
Leaking blood vessels due to various causes, may cause swelling at the macula, affecting vision.
Optical Coherence Tomography (OCT) - Showing macular edema
Medicines Given by Intra-Vitreal Injecitons:
2 major groups:
1. Anti-VEGF
Anti-Vascular Endothelial Growth Factor medicine - helps decrease the new abnormal vessels, as well as decrease swelling in the macula. The only concerns - in patients with past history of Cardiac Events and Stroke - need to be assessed and planned prior to anti-VEGF.
These Include:
Aflibercept (Eyelea)
Ranibizumab (Lucentis / Accentrix)
Brolucizumab (Beovu)
2. Steroids
Steroids act by various mechanisms to decrease the macular swelling. They are very efficient, the only concern - as a side effect in very few people may cause an increase in cataract or eye pressure. Both of which can be managed if they do occur.
These Include:
Dexamethasone Implant (Ozurdex)
Triamcinolone Acetonide
Major preparations prior to this eye procedure:
Control of blood sugar prior to injection - to avoid chances of infection inside the eye post injection
Individuals who have had previous cardiac events, or stroke must take a clearance from their treating physician prior to the injection.
Preferable use of antibiotic eye drops 3 days prior to the planned injection
While extremely rare, it's important to understand the potential chances of cataract after the injection, as the needle may potentially touch the eye lens, or the medication - steroid specifically - may cause progression of cataract . Please previously operated for cataract surgery, will obviously not be affected.
There also exists a very small chance of eye (vitreous / subretinal) bleed post injection