Intravitreal injection is a highly targeted drug therapy that has become a popular method of treatment of many retinal diseases. The injection is released into the vitreous cavity, near the retina, at the back of the eye. This method of administration has a maximum therapeutic drug delivery and minimal systemic toxicity. There are certain substances that treat specific eye diseases and help protect the vision. With the increasing use of intravitreal anti-VEGF agents, steroids, intravitreal injection has become one of the most common ophthalmic procedures performed in ophthalmology units.
What medications can be given by intravitreal injection?
- Anti-VEGF drugs: a group of medicines which reduce neovascularization (new blood vessel growth) or edema (swelling).
- Steroids, which reduce inflammation.
- Antibiotics, antiviral and antifungal medications.
Who gets intravitreal injection?
Intravitreal injections are used to administer medications to treat a variety of retinal diseases:
- Age-related macular degeneration (AMD)
- Diabetic retinopathy
- Macular edema
- Retinal vein occlusion
- Uveitis
- Endophthalmitis (a severe infection of the entire eye)
- Retinitis
The intravitreal injection procedure
Intravitreal injections are performed by retina specialists, on a daily basis in the operation room. It is important to master the techniques of effective injection for patient safety and with minimal risk complications.
The eye and the eyelids are cleaned using povidone-iodine, a yellow solution which is very effective against bacteria that live near the eye, and then the eyelid speculum is inserted.
The most important part in giving the intravitreal injection is the anesthesia of the eye. Sometimes, the way of inducing anesthesia is more painful than the injection itself, that’s why the doctor should choose the most effective and the painless option of the ComfortPack.
The types of anesthesia:
- Subconjunctival (shot into the eye)
- Topical (eye drops, gels)
- 4% Lidocaine Pledgets (ComfortPack)
Some studies revealed that the patients felt more pain when the anesthetic was being administered subconjunctival. Topical tetracaine eye drops can also be effective. Another option is to use a gel type anesthetic, such as lidocaine 2% or 3% jelly, but it is not as sterile as the doctor expects it to be.
In a similar manner, pledgets soaked with 4% lidocaine just as the ComfortPack can be placed on the eye surface and allowed to rest on the globe, then gently removed with no pain felt by the patient, nor while giving the anesthesia or during the intravitreal injection. The ComfortPack is fast, efficient and sterile. The patient will not feel pain or pressure during the intravitreal injection.
Other points to remember
- Subconjunctival anesthesia has a higher risk of a subconjunctival hemorrhage.
- If the patient is very nervous or sensitive doing subconjunctival injection can make them even more stressed because of the needle.
- If using topical anesthesia since patients feel the injection more, the risk of complications is higher because the patient can suddenly move the eye during injection.
- Modern ways of anesthesia, like ComfortPack pledgets, are of greater benefits in small surgical interventions, like intravitreal injections.
The injection is made through the pars plana, the white part of the eye, at 3-4 mm at the margin of the cornea. The entire process lasts about 10 to 15 minutes.
Follow-up Tips
- Patients may see floaters which can be an air bubble or can be the medication; especially if steroids are injected (they are white and feel in the eye like tiny clouds).
- It is important to assess the modifications after the intravitreal injection, like eye pain, redness of the eye, decreased vision, increased sensitivity to light and to ask the doctor for an appointment.
Depending on the disease being treated, a follow-up visit will be scheduled but is usually about 4 to 6 weeks after the injection.